The Number of Asteroids We Could Visit and Explore Has Just Doubled

NASA

There’s a famous line from Shakespeare’s Hamlet that says “There are more things in heaven and Earth, Horatio, than are dreamt of in your philosophy,” and the same now holds true for brave new worlds for humans to explore.

This result was published earlier this week courtesy of the NASA/JPL Near-Earth Program Office. The study found that the number of possible asteroid targets for human exploration has now doubled from the 666 known in the first study, completed in late 2010.

Credit:
NHATS NEO asteroid discoveries by year. Credit: NASA/GFSC/Brent Barbee

This information comes from NHATS, which stands for the Near Earth Object Human Spaceflight Accessible Targets Study. Yes, it’s an acronym containing acronyms. NHATS is an automated system based out of Greenbelt, Maryland which monitors and periodically updates its list of potential target candidates for accessibility. The NHATS system data is readily accessible to the public online, and as of February 11th 2015, 1346 NHATS compliant asteroids are known.

NEO orbit types.
NEA orbit types. Credit: Brent Barbee/NASA/GSFC

This is the Holy Grail for the future of manned spaceflight, and will represent a good stepping stone (bad pun intended) for future crewed missions to Mars. Several hundred NHATS asteroids require less time and energy to reach than the Red Planet, and a few dozen even require less energy to reach than it does to enter lunar orbit.

Relative delta-V and return velocity is crucial. Apollo astronauts were subject to a blistering 11 kilometre per second reentry velocity on their return from the Moon, and future asteroid missions would be subject to the same style of trajectory on return to Earth from a solar orbit.

Mission to an NEO: a typical orbital profile. credit:
Mission to an NEO: a typical orbital profile. Credit: Brent Barbee/NASA/GSFC

The test of the Orion heat shield on reentry during last year’s EFT-1 flight was a step in this direction, and the next test will be an uncrewed launch atop an SLS rocket in September 2018. If all goes according to schedule — and NASA can successfully weather the ever-shifting political winds of multiple future changes of administration — expect to see astronauts exploring an NHATS asteroid placed in lunar orbit sometime around late 2023.

I know. “When I was a kid back in the 70’s…” we expected to be vacationing on Callisto by 2015, as well.

Brent Barbee at NASA’s Goddard Space Flight Center designed the automated NHATS system. It pulls data from a source that many comet and asteroid hunters are familiar with: JPL’s Small Bodies Database. The NHATS system then makes trajectory calculations and patches in conical solutions for possible spacecraft trajectories and actually gives potential launch window dates for future missions. Seriously, its fun to play with… you can even tailor and filter these by target dates versus maximum velocity constraints and the length of stays.

NASA/JPL
The orbit of asteroid 1943 Anteros. Credit: NASA/JPL.

The first discovered NHATS-compliant NEO was 2.3 kilometre 1943 Anteros way back in 1973, and famous alumni on the NHATS list also include 10 metre asteroid 2011 MD, which passed 12,000 kilometres from the Earth on June 27th, 2011. 2011 MD is on NASA’s short list of asteroids ideal for human exploration. Another famous asteroid on the NHATS list is 99942 Apophis which — triskaidekaphobics take note — will safely miss the Earth by 31,300 kilometres on Friday the 13th, April 2029.  More are added every day, and the growing curve of discoveries also closely mirrors the rise of automated all-sky surveys such as LINEAR, PanSTARRS and the Catalina Sky Survey, though dedicated amateurs do get in on the act occasionally as well.

To date, over 12,000 NEA asteroids are now known, and you can expect future surveys such as the Large Synoptic Survey Telescope set to see first light in 2021 to add to their ranks. The Sentinel space telescope set to launch in 2017 will also boost the known number of NEOs as it covers our sunward blind spot from an orbit interior to the Earth’s. Remember Chelyabinsk? That could actually be a great rallying cry for Sentinel’s cause, as the asteroid came at the Earth from a sunward direction and avoided the sky sweeping robotic eyes of astronomers.

Sometimes, NEOs turn out to be returning space junk from the early Space Age (a low relative velocity and low orbital inclination is often a dead giveaway). Earth has also been known to capture an NEO as an occasional temporary second Moon, as occurred in 2006 in the case of asteroid 2006 RH120.

The LSST mirror in the Tuscon Mirror Lab. Photo by author.
The LSST mirror in the Tuscon Mirror Lab. Photo by author.

But beyond just creating a database, the NHATS system also presents key opportunities for astronomers to perform follow-up observations of NEO asteroids, which is vital for precisely characterizing their orbits. Two future missions are also planned to return samples from NHATS asteroids: Hayabusa 2, which launched on December 3rd 2014 headed for asteroid 1999 JU3 in July 2018, and the OSIRIS-REx mission, set to launch in late 2016 headed for asteroid 101955 Bennu in 2018.

NHATS is providing a crucial target list for that day when first human footfall on an asteroid occurs… or should we say docking?

You’ve Never Seen the Phases of the Moon from This Perspective: The Far Side

Credit

Sometimes, it seems to be a cosmic misfortune that we only get to view the universe from a singular vantage point.

Take the example of our single natural satellite. As the Moon waxes and wanes through its cycle of phases,  we see the familiar face of the lunar nearside. This holds true from the day we’re born until the day we die. The Romans and Paleolithic man saw that same face, and until less than a century ago, it was anyone’s guess as to just what was on the other side.

Enter the Space Age and the possibility to finally get a peek at the universe from different perspective via our robotic ambassadors. This week, the folks over at NASA’s Scientific Visualization Studio released a unique video simulation that utilized data from NASA’s Lunar Reconnaissance Orbiter to give us a view unseen from Earth. This perspective shows just what the phases of the Moon would look like from the vantage point of the lunar farside:

You can see the Moon going through the synodic 29.5 day period a familiar phases, albeit with an unfamiliar face. Note that the Sun zips by, as the lunar farside wanes towards New. And in the background, the Earth can be seen, presenting an identical phase and tracing out a lazy figure eight as it appears and disappears behind the lunar limb.

Credit
The lunar nearside: A familiar view. Credit: Stephen Rahn.

What’s with the lunar-planetary game of peek-a-boo? Well, the point of view for the video assumes that your looking at down at the lunar farside from a stationary point above the Moon. Note that the disk of the Moon stays fixed in place. The Moon actually ‘rocks’ or nods back and forth and side-to-side in motions referred to as libration and nutation, and you’re seeing these expressed via the motion of the Earth in the video.  This assures that we actually get a peek over the lunar limb and see a foreshadowed extra bit of the lunar farside, with grand 59% of the lunar surface visible from the Earth. Such is the wacky motion of our Moon, which gave early astronomers an excellent crash course in celestial mechanics 101.

Now, to dispel some commonly overheard lunar myths:

Myth #1: The moon doesn’t rotate. Yes, it’s tidally locked from our perspective, meaning that it keeps one face turned Earthward. But it does turn on its axis in lockstep as it does so once every 27.3 days, known as a sidereal month.

Myth #2:  The Farside vs. the Darkside. (Cue Pink Floyd) We do in fact see the dark or nighttime side of the Moon just as much as the daytime side. Despite popular culture, the farside is only synonymous with the darkside of the Moon during Full phase.

Humanity got its first glimpse of the lunar farside in 1959, when the Soviet Union’s Luna 3 spacecraft looked back as it flew past the Moon and beamed us the first blurry image. The Russians got there first, which is why the lunar farside now possesses names for features such as the “Mare Moscoviense”.

Credit
Our evolving view of the lunar farside over 60 years… Credit: NASA/LRO.

Think we’ve explored the Moon? Thus far, no mission – crewed or otherwise – has landed on the lunar farside. The Apollo missions were restricted to nearside landing sites at low latitudes with direct line of sight communication with the Earth. The same goes for the lunar poles: the Moon is still a place begging for further exploration.

Credit
China’s Chang’e 5 T1 pathfinder mission looks back at the Earth and the lunar farside. Credit: Xinhua/SASTIND.

Why go to the lunar farside? Well, it would be a great place to do some radio astronomy, as you have the bulk of the Moon behind you to shield your sensitive searches from the now radio noisy Earth. Sure, the dilemmas of living on the lunar farside might forever outweigh the benefits, and abrasive lunar dust will definitely be a challenge to lunar living… perhaps an orbiting radio astronomy observatory in a Lissajous orbit at the L2 point would be a better bet?

Credit
An artist’s conception of LRO in lunar orbit. Credit: NASA/LRO.

And exploration of the Moon continues. Earlier this week, the LRO team released a finding suggesting that surface hydrogen may be more abundant on the poleward facing slopes of craters that litter the lunar south pole region. Locating caches of lunar ice in permanently shadowed craters will be key to a ‘living off of the land’ approach for future lunar colonists… and then there’s the idea to harvest helium-3 for nuclear fusion (remember the movie Moon?) that’s still science fiction… for now.

Perhaps the Moonbase Alpha of Space: 1999 never came to pass… but there’s always 2029!

By Jove: Jupiter Reaches Opposition on February 6th

Jupiter +Great Red Spot as seen on January 22nd 2015. Credit:

Did you see the brilliant Full Snow Moon rising last night? Then you might’ve also noticed a bright nearby ‘star’. Alas, that was no star, but the largest planet in our solar system, Jupiter. And it was no coincidence that the king of the gas giants is near the Full Moon this February, as Jupiter reaches opposition this Friday on February 6th at 18:00 Universal Time or 1:00 PM EST.

As the term implies, opposition simply means that an outer planet sits opposite to the Sun. Mercury and Venus can never reach opposition. Orbiting the Sun once every 11.9 years, oppositions for Jupiter occur once every 399 days, or roughly every 13 months. This means that only one opposition for Jupiter can happen per year max, and these events precess forward on the Gregorian calendar by about a month and move one zodiacal constellation eastward per year.

Starry Night.
The apparent path of Jupiter through Spring 2015. Created using Starry Night Education Software.

Through a telescope, Jupiter exhibits an ochre disk 40” in diameter striped with two main cloud belts. The northern equatorial belt seems permanent, while the southern equatorial belt is prone to pulling a ‘disappearing act’ every decade of so, as last occurred in 2010. The Great Red Spot is another prominent feature gracing the Jovian cloud tops, though its appeared salmon to brick-colored in recent years and seems to be shrinking.

Jupiter rotates once every 9.9 hours, fast enough that you can watch one full rotation in a single night.

Photo by author
Jupiter near opposition in 2014. Photo by author.

It’s also fascinating to watch the nightly dance of Jupiter’s four large moons Io, Europa, Ganymede and Callisto as they alternatively cast shadows on the Jovian cloud tops and disappear into its shadow. Near opposition, this shadow casting activity is nearly straight back as seen from our perspective.  Here is the tiny ‘mini-solar system’ that fascinated Galileo and further convinced him that the Earth isn’t the center of the cosmos. Jupiter has 67 moons in all, though only 4 are within range of modest sized telescopes… Even 5th place runner up Himalia is a challenge near the dazzling disk of Jove at +14th magnitude.

Also watch for a phenomenon known as the Seeliger or Opposition Effect, a sudden surge in brightness like a highway retro-reflector in the night.

Opposition 2015 finds Jupiter just across the Leo-Cancer border in the realm of the Crab. Jupiter crossed from Leo into Cancer on February 4th, and will head back into the constellation of the Lion on June 10th. Jupiter then spends the rest of 2015 in Leo and heads for another opposition next year on March 8th.

Jupiter will also make a dramatic pass just 24’ — less than the diameter of the Full Moon — from Regulus on August 11th, though both are only 11.5 degrees east of the Sun in the dusk sky. Jupiter also forms a 1 degree circle with Regulus, Mercury and Jupiter 14.5 degrees east of the Sun on August 7th.

Jupiter reaches a maximum declination north for 2015 on April 7th at 18 degrees above the celestial equator. We’re still in a favorable cycle of oppositions for Jupiter for northern hemisphere viewers, as the gas giant doesn’t plunge south of the equator until September 2016.

Looking farther ahead, Jupiter reaches east quadrature on May 4th, and sits 90 degrees elongation from the Sun as the planet and its moons cast their shadows far off to the side from our Earthly perspective. We’re still also in the midst of a plane crossing: February 5th is actually equinox season on Jupiter! This also means that there’s still a cycle of mutual eclipses and occultations of the Jovian moons in progress. One such complex ballet includes (moons) on the night of February 26th.

February 26th. Starry Night
The close grouping of Io, Callisto and Ganymede on the night of February 26th. Created using Starry Night Education software.

And yes, it is possible to see the Earth transit the disk of the Sun from Jove’s vantage point. This last occurred in 2014, and will next occur in 2020.

But wait, there’s more. Jupiter also makes a thrilling pass near Venus on July 1st, when the two sit just 0.4 degrees apart. We fully expect a spike in “what are those two bright stars?” queries right around that date, though hopefully, the conjunction won’t spark any regional conflicts.

Stellarium
Jupiter, Regulus and the rising waning gibbous Moon on the evening of February 4th. Credit: Stellarium.

Solar conjunction for Jupiter then occurs on August 26th, with the planet visible in the Solar Heliospheric Observatory’s (SOHO) LASCO C3 camera from August 16th to September 6th.

Emerging into the dawn sky, Jupiter then passes 0.4 degrees from Mars on October 17th and has another 1.1 degree tryst with Venus on October 26th.

Looking for Jupiter in the daytime near the waxing gibbous Moon. Credit: Stellarium.
Looking for Jupiter in the daytime near the waxing gibbous Moon. Credit: Stellarium.

Let the Jovian observing season begin!

-Wonder what a gang of rogue space clowns is doing at Jupiter? Read Dave Dickinson’s original tale Helium Party and find out!

This Comparison of Comet 67/P With Other Solar System Bodies Will Blow Your Mind

Credit:

There’s darkness out there in the cold corners of the solar system.

And we’re not talking about a Lovecraftian darkness, the kind that would summon Cthulhu himself.  We’re talking of celestial bodies that are, well. So black, they make a Spinal Tap album cover blinding by comparison.

We recently came across the above true color comparison of Comet 67/P Churyumov-Gerasimenko adjusted for true reflectivity contrasted with other bodies in the solar system. 67/P is definitely in the “none more black” (to quote Nigel Tufnel) category as compared to, well, nearly everything.

Welcome to the wonderful world of albedo. Bob King wrote a great article last year discussing the albedo of Comet 67/P. The true albedo (or lack thereof) of 67/P as revealed by Rosetta’s NAVCAM continues to astound us. Are all comets this black close up? After all, we’re talking about those same brilliant celestial wonders that can sometimes be seen in the daytime, and are the crimson harbingers of regal change in The Game of Thrones, right?

There was also a great discussion of the dark realms of 67/P in a recent SETI Talk:

As with many things in the universe, it’s all a matter of perspective. If you live in the U.S. Northeast and are busy like we were earlier today digging yourself out from Snowmageddon 2015, then you were enjoying a planetary surface with a high albedo much more akin to Enceladus pictured above. Except, of course, you’d be shoveling methane and carbon dioxide-laced snow on the Saturnian moon… Ice, snow and cloud cover can make a world shinny white and highly reflective. Earthshine on the dark limb of the crescent Moon can even vary markedly depending on the amount of cloud and snow cover on the Earth that’s currently rotated moonward.

Earthshine or the 'Old Moon in the New Moon's arms' from earlier this week. Photo by author.
A brilliant Earthshine, or the ‘Old Moon in the New Moon’s arms’ from earlier last week. Photo by author.

To confound this, apparent magnitude over an extended object is diffused over its surface area, making the coma of a comet or a nebula appear fainter than it actually is. Engineers preparing for planetary encounters must account for changes in light conditions, or their cameras may just record… nothing.

For example, out by Pluto, Charon, and friends, the Sun is only 1/1600th as bright as seen here on sunny Earth. NASA’s New Horizons spacecraft will have to adjust for the low light levels accordingly during its historic flyby this July. On the plus side, Pluto seems to have a respectable albedo of 50% to 65%, and may well turn out to look like Neptune’s large moon, Triton.

Triton as imaged by Voyager 2: a dead ringer for Pluto? Credit: NASA/JPL.
Triton as imaged by Voyager 2: a dead ringer for Pluto? Credit: NASA/JPL.

And albedo has a role in heat absorption and reflection as well, in a phenomenon known as global dimming. The ivory snows of Enceladus have an albedo of over 95%, while gloomy Comet 67/P has an albedo of about 5%, less than that of flat black paint. A common practice here in Aroostook County Maine is to take fireplace ashes and scatter them across an icy driveway. What you’re doing is simply lowering the surface albedo and increasing the absorption of solar energy to help break up the snow and ice on a sunny day.

A high albedo snow cover blanketed New England earlier this week! Photo by author.
A high albedo snow cover blanketed New England earlier this week! Photo by author.

Ever manage to see Venus in the daytime?  We like to point out the Cytherean world in the daytime sky to folks whenever possible, often using the nearby Moon as a guide. Most folks are amazed at how easy this daytime feat of visual athletics actually is, owing to the fact that the cloud tops of Venus actually have a higher albedo of 90%, versus the Moon’s murky 8 to 12%.

Venus (upper left) by daylight. Photo by author.
Venus (upper left) by daylight. Photo by author.

Apollo 12 command module pilot Richard Gordon remarked that astronauts Al Bean and Pete Conrad looked like they’d been “playing in a coal bin” on returning from the surface of the Moon. And in case you’re wondering, Apollo astronauts reported that moondust smelled like ‘burnt gunpowder’ once they’d unsuited.

The surface of the Moon closeup: darker than you think! Credit: Apollo 12/NASA.
The surface of the Moon closeup: darker than you think! Credit: Apollo 12/NASA.

Magnitude, global dimming and planetary albedo may even play a role in SETI as well, as we begin to image Earthlike exoplanets… will our first detection of ET be the glow of their cities on the nightside of their homeworld? Does light pollution pervade the cosmos?

And a grey cosmos awaits interstellar explorers as well. Forget Captain Kirk chasing Khan through a splashy, multi-hued nebula: most are of the light grey to faded green varieties close up. Through a telescope, most nebulae are devoid of color. It’s only when a long time exposure is completed that colors too faint to see with the naked eye emerge.

All strange thoughts to consider as we scout out the dark corners of the solar system. Will the Philae lander reawaken as perihelion for Comet 67/P approaches on August 13th, 2015? Will astronauts someday have to navigate over the dark surface of a comet?

I can’t help but think as I look at the duck-like structure of 67/P that one day, those two great lobes will probably separate in a grand outburst of activity. Heck, Comet 17P/Holmes is undergoing just such an outburst now — one of the best it has generated since 2007 — though it’s still below +10th magnitude. How I’d love to get a look at Comet 17P/Holmes up close, and see just what’s going on!

 

iPhone Astrophotography: How to Take Amazing Images of the Sky with Your Smartphone Tonight!

All photos credit and copyright: Andrew Symes.

Got a smartphone and a telescope?

It’s a sight now common at many star parties. Frequently, you see folks roaming through the darkness, illuminated smartphone aimed skyward. Certainly, the wealth of free planetarium apps has done lots to kindle a renewed interest in the night sky.

Inevitably, after peering through the eyepiece of a telescope, the question then arises:

“Can I get a picture of that with my phone?”

The short answer is yes, with a little skill and patience.

Now simply aiming a camera at the eyepiece of a telescope — known as afocal astrophotography — and shooting without removing the camera lens and physically coupling it to the telescope is a tricky balancing act. Back in the olden days, the Moon and perhaps the brighter planets were the only bright target within bounds of afocal film photographers, and only then after a lengthy set of estimations to hit the correct focal length. The advent of digital cameras and ‘live preview’ means that you can now simply aim, shoot, and throw away or delete anything off center or out of focus. Digital ‘film’ is cheap, and most folks simply use trial and error to get the ‘keepers’. The Moon is an especially bright and easy target for beginners to practice on.

Moon
A gibbous Moon, an easy first pic!

Of course, your typical smartphone, like a webcam, has an imaging chip much smaller than a DSLR. This is why astrophotographers are often tempted to take out a second mortgage (“we don’t really need that second car, do we?” is a common spousal refrain) in pursuit of excellence. Another drawback is that through a smartphone, a planet may look like an overexposed blob. A simple but effective way to get around this is to affix a light reducing filter to the eyepiece. In fact, I’ve used a variable polarizer during live broadcasts of the Virtual Star Party to great effect.  And as with webcam imaging, smartphone astrophotographers now often use automated stacking programs to clean up images and tease out detail. Being an old timer, my faves are still K3CCD Tools and Registax, though many young guns out there now use DeepSkyStacker as well.

Telescope
Andrew Symes’ imaging setup.

Now, I’ll admit, I’m an ‘Android guy,’ and I have put most of my efforts over the years into planetary imaging with a homemade webcam. We therefore sought out in-the-field expertise from someone on the forefront of iPhone astrophotography. Andrew Symes has been taking images of the solar system and beyond with his iPhone coupled to his Celestron NexStar 8” SE telescope for years. He also has one of the few handles on Twitter that we’re envious of, @FailedProtostar. He also ventures out into the chilly nights frequent to his native of Ottawa, Canada to practice his craft, as he observes in temperatures that would drop a Tauntaun.

We caught up with Andrew recently to ask him about some tips of the trade.

Sun
An ‘iPhone Sun’ shot in hydrogen alpha through a Coronado PST.

Universe Today: I know from doing webcam photography that acquiring, centering and focusing are often more than half the battle. Any tips for accomplishing these?

Andrew: Acquiring, centering, and focusing the objects I’m photographing is definitely the big challenge! To speed and simplify the process, I have a dedicated eyepiece that I use in association with my phone and adapter. Before even heading outside, I attach the adapter to this eyepiece, insert my phone, and hold the unit up to a light source to see if the camera lens is properly aligned with the eyepiece. It usually takes a bit of fiddling to get things set properly because if the adapter and eyepiece are not perfectly aligned, nothing will show up on the camera screen. It’s better to get that process out of the way in a lit environment than outside in the dark. I then set that unit aside, and use a separate “adapter-less” zoom eyepiece to locate and center the object in the telescope. Once I’ve acquired the object and am successfully tracking it, I remove my zoom eyepiece and drop in the eyepiece/adapter/phone combo. At that point, the object is usually visible on screen but out of focus since the focus required for the iPhone is different from what works for my eyes! To ensure proper focus, I display the object on my phone’s screen using a live video app called FiLMiC Pro and adjust the focus until it is sharp. I use that app because it has a digital zoom function that lets me get a closer look at the object than the standard iPhone video camera view. Only once I’m confident that I’ve achieved good focus and am tracking the object properly, will I start to record video or shoot individual frames.

A comparison
A comparison of the first image of the Orion Nebula (M42) shot in 1880 (left) with a modern iPhone image.

Universe Today: A question I always like to ask everyone… what was your biggest mistake? Are there any pitfalls to avoid?

Andrew: There are a few pitfalls to avoid when doing iPhone astrophotography. In the past, I would attach the adapter outside while the eyepiece was in the telescope but this caused a number of problems. Often, I would accidentally bump the object out of view while attaching and adjusting the adapter and have to align everything all over again. The weather is also often cold here, and it’s VERY difficult to attach the adapter properly with gloves on, so I would either get really cold hands or spend a lot of unnecessary time fumbling with the adapter with gloved hands. For those reasons, I now prepare the eyepiece/adapter/phone unit indoors in advance as described above. I also now make sure that my iPhone is fully charged before heading outdoors as I’ve found that the iPhone battery drains very quickly when the camera is running constantly — especially in cold weather. Even with an almost-full battery, there are times here in winter when the phone will simply shut down due to the low temperature so I make sure to only start capturing photos/videos once I’m completely confident in my setup.

Lovejoy
Yes, that’s Comet C/2014 Q2 Lovejoy shot with an iPhone!

Universe Today: You’re really pushing the envelope by doing deep sky astro-pics with an iPhone … anything else that you’re experimenting with or working on?

Andrew: My main focus is definitely still on iPhone astrophotography because I like the quick and “light” setup. I don’t need to bring a laptop outside and don’t need equipment that I wouldn’t normally have on me anyway (other than the adapter itself.) So, I want to keep pushing the envelope with what I can capture using the phone and my goal is now is to see how far I can go with deep-sky objects. I’d really like to add the Ring and Dumbbell Nebulae to my portfolio, for example, and see if it’s possible to grab even fainter ones. There are also some non-deep sky targets I’d like to try. I haven’t been successful at capturing a telescopic photo of the ISS, and would love to see if I can catch it transiting the Sun or Moon with my phone. I also still need to capture Uranus and Neptune to round out a solar system collage I put together in 2014!

Lastly, I’m continually experimenting with photo apps to see which are best at capturing and/or processing telescopic images, and have just started using both an iPhone 4S and iPhone 6 to take photos and video. Surprisingly, I still prefer the 4S for planetary imaging as I haven’t been able to properly capture the true colors of planets with the iPhone 6 yet. The 6 has better camera resolution but seems to be adjusting the exposure of small, faint objects like planets differently than the 4S, so I need to change my routine and techniques to compensate. The methods I’ve become accustomed to using with the 4S don’t seem to translate directly to the 6 so I have some learning yet to do!

M13
An iPhone capture of Messier 13.

Amazing stuff, for sure. And to think, we were all gas-hypering film and using absurdly long focal lengths to get blurry planetary images just a few decades ago!

-Check out more of Andrew’s images, as well as read more about how he does it.

-Got a pic, shot with a smartphone or otherwise? Send ‘em in to Universe Today!

Luna vs. the Hyades! The 1st of 13 Occultations of Aldebaran Set For January 29th

Credit:

The cosmos is continually in motion.

Be it atoms, stars or snowflakes from the latest nor’easter pounding the New England seaboard, anything worth studying involves movement. And as skies and snowbound roads clear, this Wednesday and Thursday evening will give us a reason to brave the January cold, as the waxing gibbous Moon pierces the Hyades star cluster to graze past the bright star Aldebaran.

During Thursday night’s passage, the Moon will be 78% illuminated. In a sort ‘cosmos mimics controversy’ irony, the gibbous Moon is doing its best to mimic a sky bound ‘deflategate’ football just in time for Superbowl XLIX this weekend.

Stellarium
The motion of the Moon this week across the Hyades. Credit: Stellarium.

But the January 29th event also marks the first occultation of Aldebaran for 2015.

Fun fact: At magnitude +0.8, Aldebaran is the only star brighter than +1st magnitude north of the celestial equator that the Moon can currently occult. Regulus, the runner up, shines at magnitude +1.4.  Two other second magnitude stars — Antares and Spica — lie along the Moon’s path on occasion, and up until the 2nd century BC, it was possible for the Moon to occult Pollux in the constellation Gemini as well.

There are 13 occultations of Aldebaran in 2015, and the Moon occults the star 49 times overall until the last event in the current cycle on September 3rd, 2018. Aldebaran is also occulted by the Moon more often in the current 2010-2020 decade than any other bright star. You can even spy Aldebaran near the daytime Moon with binoculars, as we did back in 1996 from North Pole, Alaska.

Credit: Occult
Maps for the 13 occultations of Aldebaran  by the Moon in 2015, click to enlarge. solid lines denote regions were the occultation occurs under dark skies. Credit: Occult 4.0.

Of course, the January 29th event is an occultation only for the high Arctic, with only a scattering of villages and distant early warning stations along the northern Nunavut coast welcoming the sequence of 2015 occultations of the bright star.

The rest of us will see a close photogenic pass, as the Moon makes an end run through the Hyades star cluster every 27.3 day sidereal lunar month in 2015. The Moon will thus occult several members of the Hyades on each pass. Our best bet for North America is the occultation of Aldebaran on November 26th, though the Moon will be just 13 hours past Full.

68 Tauri. Credit: Occult 4.0
The occultation of 68 Tauri (a member of the Hyades) for January 29th. Credit: Occult 4.0.

Why doesn’t the path of the Moon just stay put with respect to the sky? Because the orbit of our Moon is fixed at an inclination of 5.1 degrees not with respect to our equator, but to the plane of the ecliptic. This means that the Moon’s orbit is in motion as well, and can wander anywhere from declination 28.6 degrees north to south as it cycles from a shallow to steep path every 18.6 years. We’re actually in a shallow year in 2015 (known as a minor lunar standstill) after which the apparent path of the Moon through the sky begins to widen again until April 2025.

An occultation is celestial motion that you can see in real time as a star or planet is photobomb’d by the onrushing Moon like a January snowplow… but those background stars are in motion as well.

The Hyades themselves — along with our own solar system — are moving around the galactic center. The nearest open cluster to us at 153 light years distant, the Hyades provided a unique object of study for 19th century astronomers. Astronomer Lewis Boss of the Dudley observatory spent several decades studying the proper motion — the apparent motion that a star seems to be moving across the sky from our solar system-bound perspective, measured in arc seconds — of the Hyades, and found the entire group was converging on a point in the constellation Orion near 6 hours 7’ right ascension and +7 degrees declination.

Starry Night
The imaginary convergent point of the Hyades in the night sky. Credit: Starry Night Education software.

Of course, this motion is relative and demonstrates a changing perspective, as the Hyades recedes from our solar system like a defensive line rushing to sack a quarterback.

OK, enough with the sports similes. The Hyades are so close that the actual Hyades Stream — often referred to as the Hyades Moving Group — is actually strewn across the constellations Orion, Taurus and Aries and more.

Some stars, such as 20 Arietis in the adjacent constellation Aries and Iota Horologii in the southern hemisphere may actually members as well. There’s always a bit of ongoing controversy when it comes to actual moving group membership, which is usually pegged by determining proper motion, coupled with the age and metallicity of prospective stars. Growing up in the Milky Way galaxy, our Sun was once a member of some unnamed ancient open cluster that has since long dispersed, like the Hyades are in the process of doing now.

Photo by author
The asterism of the Hyades and the ‘eye of the Bull.’ Photo by author.

The Hyades contains hundreds of stars and ironically, Aldebaran is not a member of the cluster, but is merely 65 light years away from us in the foreground. The V-shaped asterism of the Hyades gives the Head of Taurus the Bull its distinctive shape. The Hyades are named after the rain nymph daughters of Atlas from Greek mythology, whose half daughters the Pleiades also adorn the nearby sky.

And as an added bonus, don’t miss comet C/2014 Q2 Lovejoy crossing the constellation Triangulum, also nearby. Q2 Lovejoy reaches perihelion this week on January 30th, and although it’s completing with the evening Moon, it’s still holding out at a respectable magnitude +4.5.

Credit:
Comet Q2 Lovejoy skirts by  the Hyades and the Pleiades. Credit and Copyright: John Chumack.

All reasons to get out these chilly January evenings and ponder a hurried universe continually in motion, both fast and slow.

-Check out Q2 Lovejoy on January 30th courtesy of the Virtual Telescope project.

 

Rare Triple Transit! There’ll be 3 Moon Shadows on Jupiter on January 24th, 2015

Credit:

Play the skywatching game long enough, and anything can happen.

Well, nearly anything. One of the more unique clockwork events in our solar system occurs this weekend, when shadows cast by three of Jupiter’s moons can be seen transiting its lofty cloud tops… simultaneously.

How rare is such an event? Well, Jean Meeus calculates 31 triple events involving moons or their shadows occurring over the 60 year span from 1981 to 2040.

But not all are as favorably placed as this weekend’s event. First, Jupiter heads towards opposition just next month. And of the aforementioned 31 events, only 9 are triple shadow transits. Miss this weekend’s event, and you’ll have to wait until March 20th, 2032 for the next triple shadow transit to occur.

Hubble spies a triple shadow transit  on March 28th, 2004 . Credit: NASA/JPL/Arizona.
Hubble spies a triple shadow transit on March 28th, 2004 . Credit: NASA/JPL/Arizona.

Of course, double shadow transits are much more common throughout the year, and we included some of the best for North America and Europe in 2015 in our 2015 roundup.

The key times when all three shadows can be seen crossing Jupiter’s 45” wide disk are on the morning of Saturday, January 24th starting at 6:26 Universal Time (UT) as Europa’s shadow ingresses into view, until 6:54 UT when Io’s shadow egresses out of sight. This converts to 1:26 AM EST to 1:54 AM EST. The span of ‘triplicate shadows’ only covers a period of slightly less than 30 minutes, but the action always unfolds fast in the Jovian system with the planet’s 10 hour rotation period.

The view at 6:41 UT/1:41 AM EST. Credit: Created using Starry Night Education software.
The view on January 24th at 6:41 UT/1:41 AM EST. Credit: Created using Starry Night Education software.

Unfortunately, the Great Red Spot is predicted to be just out of view when the triple transit occurs, as it crosses Jupiter’s central meridian over three hours later at 10:28 UT.

The moons involved in this weekend’s event are Io, Callisto and Europa. Now, I know what you’re thinking. Seeing three shadows at once is pretty neat, but can you ever see four?

The short answer is no, and the reason has to do with orbital resonance.

The orbital resonance of the three innermost Galilean moons. (Credit: Wikimedia Commons).
The orbital resonance of the three innermost Galilean moons. (Credit: Wikimedia Commons).

The three innermost Galilean moons of Jupiter (Io, Europa and Ganymede) are locked in a 4:2:1 resonance. Unfortunately, this resonance assures that you’ll always see two of the innermost three crossing the disk of Jupiter, but never all three at once. Either Europa or Ganymede is nearly always the “odd moon out.”

To complete a ‘triple play,’ outermost Callisto must enter the picture. Trouble is, Callisto is the only Galilean moon that can ‘miss’ Jupiter’s disk from our line of sight. We’re lucky to be in an ongoing season of Callisto transits in 2015, a period that ends in July 2016.

Perhaps, on some far off day, a space tourism agency will offer tours to that imaginary vantage point on the surface of one of Jupiter’s moons such as Callisto to watch a triple transit occur from close up. Sign me up!

Jupiter currently rises in late January around 5:30 PM local, and sets after sunrise. It is also well placed for northern hemisphere observers in Leo at a declination 16 degrees north . This weekend’s event favors Europe towards local sunrise and ‘Jupiter-set,’ and finds the gas giant world well-placed high in the sky for all of North America in the early morning hours of the 24th.

2AM local Credit: Stellarium.
Jupiter rides high to the south at 1:45 AM EST for the US East Coast. Credit: Stellarium.

Look closely. Do the shadows of the individual moons appear different to you at the eyepiece? It’s interesting to note during a multiple transit that not all Jovian moon shadows are ‘created equal’. Distant Callisto casts a shadow that’s broad, with a ragged gray and diffuse rim, while the shadow of innermost Io appears as an inky black punch-hole dot. If you didn’t know better, you’d think those alien monoliths were busy consuming Jupiter in a scene straight out of the movie 2010.  Try sketching multiple shadow transits and you’ll soon find that you can actually identify which moon is casting a shadow just from its appearance alone.

The orientation of Earth's nighttime shadow at mid-triple transit. Credit: Created using Orbitron.
The orientation of Earth’s nighttime shadow at mid-triple transit. Credit: Created using Orbitron.

Other mysteries of the Galilean moons persist as well. Why did late 19th century observers describe them as egg-shaped? Can visual observers tease out such elusive phenomena as eruptions on Io by measuring its anomalous brightening? I still think it’s amazing that webcam imagers can now actually pry out surface detail from the Galilean moons!

Photo by author.
The 2004 triple shadow transit. Photo by author.

Observing and imaging a shadow transit is easy using a homemade planetary webcam. We’d love to see someone produce a high quality animation of the upcoming triple shadow transit. I know that such high tech processing abilities — to include field de-rotation and convolution mapping of the Jovian sphere — are indeed out there… its breathtaking to imagine just how quickly the fledgling field of ad hoc planetary webcam imaging has changed in just 10 years.

The moons and Jupiter itself also cast shadows off to one side of the planet or the other depending on our current vantage point. We call the point when Jupiter sits 90 degrees east or west of the Sun quadrature, and the point when it rises and sets opposite to the Sun is known as opposition.  Opposition for Jupiter is coming right up for 2015 on February 6th. During opposition, Jupiter and its moons cast their respective shadows nearly straight back.

Did you know: the speed of light was first deduced by Danish astronomer Ole Rømer in 1671 using the discrepancy he noted while predicting phenomena of the Galilean moons at quadrature versus opposition. There were also early ideas to use the positions of the Galilean moons to tell time at sea, but it turned out to be hard enough to see the moons and their shadows with a small telescope based on land, let alone from the pitching deck of a ship in the middle of the ocean.

And speaking of mutual events, we’re still in the midst of a season where it’s possible to see the moons of Jupiter eclipse and occult one another. Check out the USNO’s table for a complete list of events, coming to a sky near you.

And let’s not forget that NASA’s Juno spacecraft is headed towards Jupiter as well., Juno is set to enter a wide swooping orbit around the largest planet in the solar system in July 2016.

Now is a great time to get out and explore Jove… don’t miss this weekend’s triple shadow transit!

Read Dave Dickinson’s sci-fi tale of astronomical eclipse tourism through time and space titled Exeligmos.

Beagle 2: Found on Mars After An 11 Year Hunt

Credit & Coyright:

The final chapter in the saga of a wayward Mars lander was finally revealed today, as an international team released images showing the Beagle-2 lander’s final resting place on Mars.

Flashback to Christmas Day, 2003. While most folks gathered ‘round the tree and opened presents, the UK and European Space Agency awaited a gift from space.  The Beagle-2 Mars lander had been released from the European Space Agency’s Mars Express orbiter six days prior, and was coasting towards a perilous landing in Isidis Planitia and was set to phone home.

All was going according to plan, and then… silence.

It’s the worst part of any mission, waiting for a lander to call back and say that it’s safe and sound on the surface of another world. As the hours turned into days, anxious engineers used NASA’s Mars Odyssey spacecraft and the Lovell Telescope at Jodrell Bank to listen for the signal.

Beagle-2 was declared lost a few weeks later on February 6th, 2004.

But now, there’s a final twist to the tale to tell.

Beagle 2
Beagle 2, partially deployed on the Martian surface. Credit and Copyright: HiRISE/NASA/Leicester.

The UK Space Agency, working with ESA and NASA announced today that debris from the landing site had been identified and that indicates — contrary to suspicions — that Beagle-2 did indeed make it to the surface of the Red Planet intact. New images from the Mars Reconnaissance Orbiter released today suggest that not only did Beagle-2 land, but that its airbags did indeed deploy properly and that the dish-shaped 1-meter in diameter spacecraft partially unfolded pocket-watch style after it had bounced to a stop.

“We are very happy to learn that Beagle 2 touched down on Mars,” said ESA’s Director of Science and Robotic Exploration in a recent press release. “The dedication of the various teams in studying high-resolution images in order to find the lander is inspiring.”

So, what went wrong with Beagle-2?

At this point, no further speculation as to what caused the lander to fall silent has been forthcoming, but today’s revelation is sure to rewrite the final saga of Beagle-2.

“Not knowing what happened to Beagle-2 remained a nagging worry,” said ESA’s Mars Express project manager Rudolf Schmidt. “Understanding now that Beagle-2 made it all the way down to the surface is excellent news.”

Speculation swirled across the internet earlier this week as the UK Space Agency and ESA suggested that new information as to the fate of Beagle-2 was forthcoming, over 11 years after the incident. Back in 2004, it was suggested that Beagle-2 had encountered higher levels of dust in the Martian atmosphere than expected, and that this in turn resulted in a failure of the spacecraft’s parachutes. Presumably, the lander then failed to slow down sufficiently and crashed on the surface of Mars, the latest victim of the Great Galactic Ghoul who seems to love dining on human-built spacecraft bound for the Red Planet.

Credit: ESA
An artist’s conception of Beagle-2 fully deployed on Mars. Credit: ESA.

The loss of Beagle-2 wasn’t only a blow to the UK and ESA, but to its principal investigator Colin Pillinger as well. Pillinger was involved in the search for Beagle-2 in later years, and also played a part in the Rosetta mission to Comet 67P/Churyumov-Gerasimenko as well. Unfortunately, Pillinger passed away in May of last year from a brain hemorrhage. A portion of the western rim of Endeavour Crater currently being explored by Opportunity was named Pillinger Point in his honor.

Today’s announcement has triggered a wave of congratulations that the 11-year mystery has been solved. There have even been calls on Twitter and social media to rename the Beagle-2 site Pillinger Station.

“The history of of space exploration is marked by both success and failure,” Said Dr. David Parker, the Chief Executive of the UK Space Agency in a recent press release. “This finding makes the case that Beagle-2 was more of a success than we previously knew and undoubtedly an important step in Europe’s continuing exploration of Mars.”

Click here for the animated .gif version.
Evidence of the successful landing of Beagle-2. Click here for the animated .gif version. Credit: University of Leicester/Beagle 2/NASA/University of Arizona.

Beagle-2 is about 2 metres across unfurled, and came to rest within 5 kilometres of its target location.

There have been false announcements of the discovery of Beagle-2 before. Back in late 2005, a claim was made that the lander had been spotted by Mars Global Surveyor, though later searches came to naught.

“I can imagine the sense of closure that the Beagle-2 team must feel,” Said JPL’s MRO project scientist Richard Zurek in a recent press release. “MRO has helped find safe landing sites on Mars for the Curiosity and Phoenix missions and has searched for missing craft to learn what may have gone wrong. It’s an extremely difficult task.”

MRO entered orbit in March 2006 and carries a 0.5 metre in diameter HiRISE camera capable of resolving objects just 0.3 metres across on the surface of Mars.  The European Space Agency’s Mars Express orbiter that carried Beagle 2 is also still in operation, along with NASA’s aging Mars Odyssey spacecraft. These were joined in orbit by MAVEN and India’s Mars Orbiter just last year.

All rights reserved Beagle 2.
Beagle-2 encapsulated in the lab. All rights reserved, Beagle-2.

Of course, getting to Mars is tough, and landing is even harder. Mars has just enough atmosphere that you have to deal with it, but it’s so tenuous – 0.6% the surface pressure of Earth’s atmosphere at sea level – That it doesn’t provide a whole lot of usable drag.

To date, only NASA had successfully landed on Mars, and done it seven times – only the Mars Polar Lander failed back in 1999. The Russians fared much worse, with their most successful lander being Mars 3, which sent back only one blurry image before falling silent.

ESA and the Russian Federal Space Agency hope to amend that with the launch of the ExoMars mission next year, slated to land on Mars in 2018.

I remember waiting with millions of other space fans for word back from Beagle 2 on Christmas Day 2003. Think back to what your internet connection was like over 11 years ago, in an era before smart phones, Twitter and Facebook. We’d just come off of the spectacular 2003 Mars opposition season, which provided the orbital geometry ideal for launching a mission to the Red Planet. This window only comes around once every 26 months.

Though Beagle 2 was a stationary lander akin to the Viking and Mars Phoenix missions, it had a robotic arm and a clever battery of experiments, including ones designed to search for life. The signal it was supposed to use to call home was designed by the UK pop rock band Blur, a jingle that never came.

Alas, we’ll have to wait to see what the alien plains around Isidis Planitia actually look like, just 13 degrees north of the Martian equator. But hey, a lingering mystery of the modern age of planetary exploration was solved this week.

Still, we’re now left with a new dilemma. Does this mean we’ll have to write a sequel to our science fiction short story The Hunt for Beagle?

-Read free original science fiction from Dave Dickinson every Friday, including ongoing chapters from The Hunt for Beagle.

 

 

 

 

Challenge Yourself! See an Astronomical Event that Only Happens Once Every 26 Years

This artist’s impression shows an eclipsing binary star system. Credit: ESO/L. Calçada.

Update: It’s off. This past weekend, the AAVSO issued Special Notice #395 calling off the campaign to observe Alpha Comae Berenices this month due to “position measurements published a century ago (which) contained errors that affected the predictions for the time of eclipse…”

And the mystery of Alpha Comae Berenices continues. Oh well. Such is the wiles and whims of the universe, and the exciting field of variable star observing!

A truly fascinating event may be in the offing this month.

Picture two distant burning embers (candles, light bulbs, LEDs, what have you) circling each other in the distance. From our far-flung vantage point, the two points of light are too faint to resolve individually, but as they pass in front of each other, a telltale dip in combined brightness occurs as one blocks out the other.

Welcome to the fascinating world of eclipsing binary stars. This week, we’d like to turn our attention towards a special star in the constellation of Coma Berenices which may — or may not — put on such a dimming act later this month.

Starry Night
An Alpha Comae Berenices (Diadem) finder chart, with comparison stars and magnitudes, decimals omitted. Credit: Starry Night Education Software.

The brightest star in the constellation Coma Berenices, Alpha (sometimes referred to as Diadem, or the ‘crown’ of Queen Berenice) shines at an apparent magnitude of +4.3. Located 63 light years distant, the system consists of two +5th magnitude F-type stars each about 3 times more luminous than our Sun locked in a 26 year orbital embrace. The physical separation of the pair is about 10 astronomical units: place Alpha Comae Berenices in our solar system, and the pair would fit nicely between the Sun and Saturn.

The orbital plane of the pair is inclined nearly along our line of sight as seen from the Earth, and it’s long been thought that catching a grazing or central eclipse of the pair might just be possible. No eclipse was recorded last time ‘round back in February 1989, but times have changed lots in observational astronomy. Today, there are enough backyard observers armed with dedicated observatories and rigs that’d be the envy of a small university that documenting such an eclipse might just be possible. In fact, a central eclipse might just dim the star by 0.8 magnitudes, and should be noticeable to the naked eye.

The binary nature of Alpha Comae Berenices was first noted by F. G. W. Struve in 1827, and the split is a challenging one during the best of years with a maximum angular separation of just 0.7 arc seconds. The pair also has a third faint +10th magnitude companion located about 89 arc seconds away.

Simplified
A simplified diagram depicting an eclipsing binary event along our line of sight. Created by the author.

The American Association of Variable Star Observers (AAVSO) has an Alert Notice calling for sky watchers worldwide to monitor the star. We also understand the orbit of Alpha Comae Berenices much better in 2015 than back in 1989, and the suspected eclipse should occur somewhere between January 22nd and January 28th and may last anywhere from 28 to 45 hours. This lingering ambiguity means that having a dedicated team of observers worldwide may well be key to nabbing this eclipse.

Bootes-Labeled
Alpha Comae Berenices rising. Photo by the author.

The Navy Precision Optical Interferometer (NPOI) has already begun refining measurements of the brightness of the star last month, and professional facilities, to include the Fairborn Observatory atop Mt Hopkins in Arizona and the CHARA (the Center for High Angular Resolution Astronomy) Array at Mount Wilson Observatory in southern California will also be monitoring the event.

Sky and Telescope magazine also has an excellent article in their January 2015 issue on the prospects for catching this eclipse.

Stellarium
Looking eastward past local midnight. Credit: Stellarium.

In late January, the constellation of Coma Berenices rises high to the northeast just after local midnight.  It’s worth noting that, if the eclipsing binary nature of Alpha Comae Berenices is confirmed, it would be the longest period known, beating out 14.6 year Gamma Persei discovered in 1990 by more than a decade. A system with as wide a separation as Alpha Comae Berenices would have about a 1 in 1,200 chance in eclipsing along our line of sight due to random chance.

Note: Epsilon Aurigae does have a comparable 27 year period involving a debris disk surrounding its host star. Thanks to sharp-eyed reader Dr. John Barentine for pointing this out!

Of course, the universe does provide us with lots of near misses, allowing for an ‘occasional Diadem’ to indeed occur. Most famous eclipsing variables, such as Algol or Beta Lyrae have periods measured over the span of days or hours. Incidentally, these also make great ‘practice stars’ to test your skills as a visual athlete leading up to the big event next week. A skilled visual observer can note a change as slight as a 0.1 of a magnitude, and it’s a good idea to begin familiarizing yourself with the environs of the star now. The Coma Cluster of galaxies, the globular cluster M53, and the galactic plane crossing intruder Arcturus all lie nearby.

Credit: NASA/Spitzer.
The Coma Cluster as seen by Spitzer Space Telescope and the Sloan Digital Sky Survey. Credit: NASA/Spitzer.

Why study eclipsing binaries? Well, said fleeting mutual events when coupled with spectroscopic measurements and determinations of parallax can tell us a good deal about the astrophysical nature of the stars involved. Eclipsing binary stars have even been used to back up standard candle measurements over extragalactic distances. And of course, orbiting observatories such as Kepler and TESS (to be launched in 2017) look for transiting exoplanets using virtually the same method.

Credit: Brad Timerson.
Have a scope+DSLR? Then you can make refined measurements of eclipsing variable stars. Credit: Brad Timerson/IOTA.

But beyond its practical application, we just think that it’s plain cool that you can actually see something out beyond our solar system changing in the span of just a few days or hours.

Observers also still carry out visual observations of variable stars, just like those pipe-smoking, pocket watch carrying astronomers of yore. This involves merely comparing the target star to nearby stars of the same brightness. If you have a DSLR or a CCD rig plus a telescope, the AAVSO also has instructions for how to monitor a star’s brightness as well. No pocket watch required.

A homemade interferometer used to measure the separation of close double stars.
A homemade ‘card interferometer’ used to measure the separation of close double stars. Photo by author.

Unless, of course, you want to carry a pocket watch just for good luck. Don’t let the cold January winters keep you from joining the hunt. Let’s make some astrophysical history!

 

 

New Finds From Kepler: 8 New Worlds Discovered in the Habitable Zone

An artist's conception of one of the newly released exo-worlds, a planet orbiting an ancient planetary nebula. Credit: David A. Aguilar/CfA.

A fascinating set of finds was announced today at the 225th meeting of the American Astronomical Society (AAS), currently underway this week in Seattle, Washington. A team of astronomers announced the discovery of eight new planets potentially orbiting their host stars in their respective habitable zones. Also dubbed the ‘Goldilocks Zone,’ this is the distance where — like the tempting fairytale porridge — it’s not too hot, and not too cold, but juuusst right for liquid water to exist.

And chasing the water is the name of the game when it comes to hunting for life on other worlds. Two of the discoveries announced, Kepler-438b and Kepler-442b, are especially intriguing, as they are the most comparable to the Earth size-wise of any exoplanets yet discovered.

“Most of these planets have a good chance of being rocky, like Earth,” said Guillermo Torres in a recent press release. Guillermo is the lead author in the study for the Harvard-Smithsonian Center for Astrophysics (CfA).

This also doubles the count of suspected terrestrial exo-worlds — planets with less than twice the diameter of the Earth — inferred to orbit in the habitable zone of their host stars.

Fans on exoplanet science will remember the announcement of the first prospective Earth-like world orbiting in the habitable zone of its host star, Kepler-186f announced just last year.

The Kepler Space Telescope looks for planets used a technique known as the transit method. If a planet is orbiting its host star along our line of sight, a small but measurable dip in the star’s brightness occurs. This has advantages over the radial velocity technique because it allows researchers to pin down the hidden planet’s orbit and size much more precisely. The transit method is biased, however, to planets close in to its host which happen to lie along our solar system-bound line of sight. Kepler may miss most exo-worlds inclined out of its view, but it overcomes this by staring at thousands of stars.

Kepler launch
The launch of Kepler from the Cape in 2009. Credit: NASA/Kim Shiflett.

Launched in 2009, Kepler has wrapped up its primary phase of starring at a patch of sky along the plane of the Milky Way in the directions of the constellations of Cygnus, Lyra and Hercules, and is now in its extended K2 mission using the solar wind pressure as a 3rd ‘reaction wheel’ to carry out targeted searches along the ecliptic plane.

Both newly discovered worlds highlighted in today’s announcement orbit distant red dwarf stars. Kepler-438 b is estimated to be 12% larger in diameter than the Earth, and Kepler-442 b is estimated by the team to be 33% larger. These worlds have a 70% and 60% chance of being rocky, respectively. For comparison, Ice giant planet Uranus is 4 times the diameter of the Earth, and over 14 times more massive.

A comparison of the new exoplanet finds between Earth and Jupiter. Credit: NASA/Kepler.
A comparison of the new exoplanet finds between Earth and Jupiter. Credit: NASA/Kepler.

“We don’t know for sure whether any of the planets in our sample are truly habitable,” Said CfA co-researcher in the study David Kipping. All we can say is that they’re promising candidates.”

The idea of habitable worlds around red dwarf stars is a tantalizing one. These stars are fainter and cooler than our Sun, and 7.5% to 50% as massive. They also have two primary factors going for them: they’re the most common type of stars in the universe, and they have life spans measured in trillions of years, much longer than the current age of the universe. If life could go from muck to making microwave dinners here on Earth in just a few billion years, it’s had lots longer to do the same on worlds orbiting red dwarf stars.

There is, however, one catch: the habitable zone surrounding a red dwarf is much closer in to its host star, and any would-be planet is subject to frequent surface-sterilizing flares. Perhaps a world with a synchronous rotation might be spared this fate and feature a habitable hemisphere well inside the snow line permanently turned away from its host.

The team made these discoveries by sifting though Kepler’s preliminary finds that are termed KOI’s, or Kepler Objects of Interest. Though these potential discoveries were far too small to pin down their masses using the traditional method, the team employed a program named BLENDER to statically validate the finds. BLENDER has been employed before in concert with backup observations for extremely tiny exoplanet discoveries. Torres and Francois Fressin developed the BLENDER program, and it is currently run on the massive Pleiades supercomputer at NASA Ames.

It was also noted in today’s press conference that two KOIs awaiting validation — 5737.01 and 2194.03 — may also prove to be terrestrial worlds  orbiting Sun-like stars that are possibly similar in size to the Earth.

The proposed target regions for the Kepler K2 mission. Credit: NASA/Kepler.
The proposed target regions for the Kepler K2 mission. Credit: NASA/Kepler.

But don’t plan on building an interstellar ark and heading off to these newly found worlds just yet. Kepler-438b sits 470 light years from Earth, and Kepler-442b is even farther away at 1,100 light years. And we’ll also add our usual caveat and caution that, from a distance, the planet Venus in our own solar system might look like a tempting vacation spot. (Spoiler alert: it’s not).

Still, these discoveries are fascinating finds and add to the growing menagerie of exoplanet systems. These will also serve as great follow up targets for TESS, Gaia and LSST survey, all set to add to our exoplanet knowledge in the coming decade.

The LSST mirror in the Tuscon Mirror Lab. (Photo by author).
The LSST mirror in the Tuscon Mirror Lab. (Photo by author).

And to think, I remember growing up as a child of the 1970s reading that exoplanet detections were soooo difficult that they might never occur in our lifetime… now, fast-forward to 2015, and we’re beginning to classify and characterize other brave new solar systems in the modern Age of Exoplanet Science.

-Looking to observe red dwarf stars with your backyard scope? Check out our handy list.