Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech
After several months with their telescope on the sidelines, the Kepler space telescope team has happy news to report: the exoplanet hunter is going to do a new mission that will compensate for the failure that stopped its original work.
Kepler’s exoplanet days were halted last year when the second of its four reaction wheels (pointing devices) failed, which meant the telescope could not gaze at its “field” of stars in the Cygnus constellation for signs of exoplanets transiting their stars.
Results of a NASA Senior Review today, however, showed that the telescope will receive the funding for the K2 mission, which allows for some exoplanet hunting, among other tasks. The telescope will essentially change positions several times a year to do its new mission, which is funded through 2016.
“The approval provides two years of funding for the K2 mission to continue exoplanet discovery, and introduces new scientific observation opportunities to observe notable star clusters, young and old stars, active galaxies and supernovae,” wrote Charlie Sobeck, the mission manager for Kepler, in a mission update today (May 16).
Artist’s rendering of the Earth-sized Kepler-186f (Credit: NASA Ames/SETI Institute/Caltech)
“The team is currently finishing up an end-to-end shakedown of this approach with a full-length campaign (Campaign 0), and is preparing for Campaign 1, the first K2 science observation run, scheduled to begin May 30.”
While Kepler itself was not being used for planet hunting, scientific discoveries continue because the telescope has a legacy of observations stretching between 2009 and 2013. One notable find: 715 exoplanets were announced in one swoop earlier this year using a new technique called “verification by multiplicity”, which is useful in multiple-planet systems.
Kepler also spotted the first known Earth-sized planet in a habitable zone outside of our solar system, which achieves the mission’s stated goal of finding extrasolar Earths.
In this comparison image the photo at the top was taken by Hubble's Wide Field Planetary Camera 2 in 1995 and shows the spot at a diameter of just under 21 000km; the second down shows a 2009 WFC3 photo of the spot at a diameter of just under 18 000km; and the lowest shows the newest image from WFC3 taken in 2014 with the spot at its smallest yet, with diameter of just 16 000km. Credit: NASA/ESA
Earlier this year we reported that amateur astronomers had observed and photographed the recent shrinking of Jupiter’s iconic Great Red Spot.Now, astronomers using the Hubble Space Telescope concur:
“Recent Hubble Space Telescope observations confirm that the spot is now just under 10,250 miles (16,500 km) across, the smallest diameter we’ve ever measured,” said Amy Simon of NASA’s Goddard Space Flight Center in Maryland, USA.
Drawing of Jupiter made on Nov. 1, 1880 by French artist and astronomer Etienne Trouvelot showing transiting moon shadows and a much larger Great Red Spot.
Using historic sketches and photos from the late 1800s, astronomers determined the spot’s diameter then at 25,475 miles (41,000 km) across. Even the smallest telescope would have shown it as a huge red hot dog. Amateur observations starting in 2012 revealed a noticeable increase in the spot’s shrinkage rate.
The spot’s “waistline” is getting smaller by just under 620 miles (1,000 km) per year while its north-south extent has changed little. In a word, the spot has downsized and become more circular in shape. Many who’ve attempted to see Jupiter’s signature feature have been frustrated in recent years not only because the spot’s pale color makes it hard to see against adjacent cloud features, but because it’s physically getting smaller.
Jupiter’s Great Red Spot or GRS is located in a ‘bay’ or hollow south of the swirly South Equatorial Belt. A titanic storm that’s raged like hurricane-like for at least 400 years, the top of the Spot’s cloud deck rises 5 miles (8 km) above the planet’s clouds and rotates in an anticlockwise direction about once every 4 days. This photo was taken by Hubble on April 21, 2014. Credit: NASA / ESA / A. Simon
As to what causing the drastic downsizing, there are no firm answers yet:
“In our new observations it is apparent that very small eddies are feeding into the storm,” said Simon. “We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics of the Great Red Spot.”
A brief primer on Jupiter’s Great Red Spot
The Great Red Spot has been a trademark of the planet for at least 400 years – a giant hurricane-like storm whirling in the planet’s upper cloud tops with a period of 6 days. But as it’s shrunk, its period has likewise grown shorter and now clocks in at about 4 days.
The storm appears to be conserving angular momentum by spinning faster the same way an ice skater spins up when she pulls in her arms. Wind speeds are increasing too, making one wonder whether they’ll ultimately shrink the spot further or bring about its rejuvenation.
Chalk up another benchmark in the fascinating and growing menagerie of extra-solar planets.
This week, an international team of researchers from the Université de Montréal announced the discovery of an exoplanet around the star GU Piscium in the constellation of Pisces the Fishes 155 light years distant. Known as GU Psc b, this world is estimated to be 11 times the mass of Jupiter — placing it just under the lower mass limit for brown dwarf status — and orbits its host star 2,000x farther than the distance from Earth to the Sun once every 80,000 (!) years. In our own solar system, that would put GU Psc b out over twice the distance of the aphelion of 90377 Sedna.
The primary star, GU Psc A, is an M3 red dwarf weighing in at 35% the mass of our Sun and is just 100 million years old, give or take 30 million years. In fact, researchers targeted GU Psc after it was determined to be a member of the AB Doradus moving group of relatively young stars, which are prime candidates for exoplanet detection. Another recent notable discovery, the free-floating “rogue planet” CFBDSIR 2149-0403 is also thought to be a member of the AB Doradus moving group.
The fact that GU Psc B was captured by direct imaging at 155 light years distant is amazing. The international team that made the discovery was led by PhD student at the Department of Physics Université de Montréal Marie-Ève Naud. The team was able to discern this curious planet by utilizing observations from the W.M. Keck observatory, the joint Canada-France-Hawaii Telescope, the Gemini Observatory and the Observatoire Mont-Mégantic in Québec.
An artist’s conception of the forlorn world of GU Psc b. Credit– Lucas Granito.
Universe Today recently caught up with researcher Marie-Ève Naud and her co-advisor Étienne Artigau about this exciting discovery.
What makes this discovery distinctive? Is this the most distant exoplanet ever imaged?
“Well, first, there are not a lot of exoplanets that were detected ‘directly’ so far. Most were found indirectly through the effect they have on their parent star. The few planets for which we have an actual image are interesting because we can analyze their light directly, and thus learn much more about them. It was also one of the “coolest” planets that have been directly imaged, showing methane absorption. And yes, it is certainly the most distant exoplanet to a main-sequence star that has been found so far.
This distance makes GU Psc b very interesting from a theoretical point of view, because it’s hard to imagine how it could have formed in the protoplanetary disk of its star. The current working definition of an exoplanet is based solely on mass (<13 Jupiter masses), so GU Psc b probably formed in a way that is more similar to how stars formed. It is definitely the kind of object that makes us think about what exactly is an exoplanet.”
At a distance of 2000 A.U.s from its primary, how are astronomers certain that PU Psc b is related to its host and not a foreground or background object?
“As the host star, GU Psc is relatively nearby; it displays a significant apparent proper motion (note: around 100 milliarcseconds a year) relative to distant background stars and galaxies.
On images taken one year apart with WIRCam on the Canada-France-Hawaii Telescope, we observed that the companion displays the same big proper motion, i.e. they move together in the plane of the sky, while the rest of the stars in the field don’t. We also determined the distance of the both the planet and the host star, and they both agree. Also, they both display signs that they are very young.”
Were any groundbreaking techniques used for the discovery, and what does this mean for the future of exoplanet science?
“Quite the opposite… most planet hunting techniques using direct imaging involve state-of-the-art adaptive optics systems, but we used ‘standard’ imaging without any exotic techniques. Planet searches usually attempt to find planets in orbits similar to those of our own solar system giants, and finding these objects, indeed, requires groundbreaking techniques. In a sense, there is an anthropocentric bias in the searches for exoplanets, as people tend to look for systems that are similar to our own solar system. Very distant planets like GU Psc b have been under the radar, even though they are easier to find than their closer-in counterparts. To find this planet, we used very sensitive ‘standard’ imaging, but we chose carefully the wavelengths where planets display colors that are unlike most other astrophysical objects such as stars and galaxies.”
The general field of GU Piscium A & B in the night sky… note that this currently puts it in the dawn sky, near Venus and Uranus! Credit: Starry Night.
GU Piscium shines at magnitude +13.6 northeast of the March equinoctial point in the constellation of Pisces. Although its exoplanet companion is too faint to be seen with a backyard telescope, its angular separation is a generous 42,” about the apparent span of Saturn, complete with rings. And it’s shaping up to be a red dwarf sort of week at Universe Today, with our recent list of red dwarf stars for backyard telescopes. And the current tally for extra-solar planets sits at 1,791… hey; didn’t we just pass 1,000 last year?
Congrats to Marie-Ève Naud and her team on this exciting new discovery… and here’s to many more to come!
An artist's conception of a red dwarf solar system. Credit: NASA/JPL-Caltech.
They’re nearby, they’re common and — at least in the latest exoplanet newsflashes hot off the cyber-press — they’re hot. We’re talking about red dwarf stars, those “salt of the galaxy” stars that litter the Milky Way. And while it’s true that there are more of “them” than there are of “us,” not a single one is bright enough to be seen with the naked eye from the skies of Earth.
A reader recently brought up an engaging discussion of what red dwarfs might be within reach of a backyard telescope, and thus this handy compilation was born.
Of course, red dwarfs are big news as possible hosts for life-bearing planets. Though the habitable zones around these stars would be very close in, these miserly stars will shine for trillions of years, giving evolution plenty of opportunity to do its thing. These stars are, however, tempestuous in nature, throwing out potentially planet sterilizing flares.
Red dwarf stars range from about 7.5% the mass of our Sun up to 50%. Our Sun is very nearly equivalent 1000 Jupiters in mass, thus the range of red dwarf stars runs right about from 75 to 500 Jupiter masses.
For this list, we considered red dwarf stars brighter than +10th magnitude, with the single exception of 40 Eridani C as noted.
The closest stars within 14 light years of our solar system. Credit: Wikimedia Commons, Public Domain graphic.
I know what you’re thinking… what about the closest? At magnitude +11, Proxima Centauri in the Alpha Centauri triple star system 4.7 light years distant didn’t quite make the cut. Barnard’s Star (see below) is the closest in this regard. Interestingly, the brown dwarf pair Luhman 16 was discovered just last year at 6.6 light years distant.
Also, do not confuse red dwarfs with massive carbon stars. In fact, red dwarfs actually appear to have more of an orange hue visually! Still, with the wealth of artist’s conceptions (see above) out there, we’re probably stuck with the idea of crimson looking red dwarf stars for some time to come.
Star
Magnitude
Constellation
R.A.
Dec
Groombridge 34
+8/11(v)
Andromeda
00h 18’
+44 01’
40 Eridani C
+11
Eridanus
04h 15’
-07 39’
AX Microscopii/Lacaille 8760
+6.7
Microscopium
21h 17’
-38 52’
Barnard’s Star
+9.5
Ophiuchus
17h 58’
+04 42’
Kapteyn’s Star
+8.9
Pictor
05h 12’
-45 01’
Lalande 21185
+7.5
Ursa Major
11h 03’
+35 58’
Lacaille 9352
+7.3
Piscis Austrinus
23h 06’
-35 51’
Struve 2398
+9.0
Draco
18h 43’
+59 37’
Luyten’s Star
+9.9
Canis Minor
07h 27’
+05 14’
Gliese 687
+9.2
Draco
17h 36’
+68 20’
Gliese 674
+9.9
Ara
17h 29’
-46 54’
Gliese 412
+8.7
Ursa Major
11h 05’
+43 32’
AD Leonis
+9.3
Leo
10h 20’
+19 52’
Gliese 832
+8.7
Grus
21h 34’
-49 01’
Notes on each:
Groombridge 34: Located less than a degree from the +6th magnitude star 26 Andromedae in the general region of the famous galaxy M31, Groombridge 34 was discovered back in 1860 and has a large proper motion of 2.9″ arc seconds per year.
Locating Groombridge 34. Created using Stellarium.
40 Eridani C: Our sole exception to the “10th magnitude or brighter” rule for this list, this multiple system is unique for containing a white dwarf, red dwarf and a main sequence K-type star all within range of a backyard telescope. In sci-fi mythos, 40 Eridani is also the host star for the planet Richese in Dune and the controversial location for Vulcan of Star Trek fame.
Locating 40 Eridani. Created using Stellarium.
AX Microscopii: Also known as Lacaille 8760, AX Microscopii is 12.9 light years distant and is the brightest red dwarf as seen from the Earth at just below naked eye visibility at magnitude +6.7.
A 20 year animation showing the proper motion of Barnard’s Star. Credit: Steve Quirk, images in the Public Domain.
Barnard’s Star: the second closest star system to our solar system next to Alpha Centuari and the closest solitary red dwarf star at six light years distant, Barnard’s Star also exhibits the highest proper motion of any star at 10.3” arc seconds per year. The center of many controversial exoplanet claims in the 20th century, it’s kind of a cosmic irony that in this era of 1790 exoplanets and counting, planets have yet to be discovered around Barnard’s Star!
Kapteyn’s Star: Discovered by Jacobus Kapteyn in 1898, this red dwarf orbits the galaxy in a retrograde motion and is the closest halo star to us at 12.76 light years distant.
Lalande 21185: currently 8.3 light years away, Lalande 21185 will pass 4.65 light years from Earth and be visible to the naked eye in just under 20,000 years.
Lacaille 9352: 10.7 light years distant, this was the first red dwarf star to have its angular diameter measured by the VLT interferometer in 2001.
Struve 2398: A binary flare star system consisting of two +9th magnitude red dwarfs orbiting each other 56 astronomical units apart and 11.5 light years distant.
Luyten’s Star: 12.36 light years distant, this star is only 1.2 light years from the bright star Procyon, which would appear brighter than Venus for any planet orbiting Luyten’s Star.
Gliese 687: 15 light years distant, Gliese 687 is known to have a Neptune-mass planet in a 38 day orbit.
Gliese 674: Located 15 light years distant, ESO’s HARPS spectrograph detected a companion 12 times the mass of Jupiter that is either a high mass exoplanet or a low mass brown dwarf.
Gliese 412: 16 light years distant, this system also contains a +15th magnitude secondary companion 190 Astronomical Units from its primary.
AD Leonis: A variable flare star in the constellation Leo about 16 light years distant.
Gliese 832:Located 16 light years distant, this star is known to have a 0.6x Jupiter mass exoplanet in a 3,416 day orbit.
The closest stars to our solar system over the next 80,000 years. Credit: FrancescoA under a Creative Commons Attribution Share-Alike 3.0 Unported license.
Consider this list a teaser, a telescopic appetizer for a curious class of often overlooked objects. Don’t see you fave on the list? Want to see more on individual objects, or similar lists of quasars, white dwarfs, etc in the range of backyard telescopes in the future? Let us know. And while it’s true that such stars may not have a splashy appearance in the eyepiece, part of the fun comes from knowing what you’re seeing. Some of these stars have a relatively high proper motion, and it would be an interesting challenge for a backyard astrophotographer to build an animation of this over a period of years. Hey, I’m just throwing that out project out there, we’ve got lots more in the files…
Artists impression of a Super-Earth, a class of planet that has many times the mass of Earth, but less than a Uranus or Neptune-sized planet. Credit: NASA/Ames/JPL-Caltech
“One of the main things we’re focused on is the notion of existential risk, getting a sense of what the probability of human extinction is,” said Andrew Snyder-Beattie, who recently wrote a piece on the “Great Filter” for Ars Technica.
It’s a key piece of the climate change puzzle. For years, researchers have been eyeing the stability of the Western Antarctic Ice Sheet as global temperatures rise. Melting of the ice sheet could have dire consequences for sea level rise.
And though not unexpected, news from today’s NASA press conference delivered by Tom Wagner, a cryosphere program scientist with the Earth Science Division of NASA’s Science Mission Directorate in Washington D.C., Sridhar Anandakrishnan, a professor of geosciences at Pennsylvania University, and Eric Rignot, JPL glaciologist and professor of Earth system science at the University of California Irvine was certainly troubling.
The key region targeted in the study (arrowed) Credit: NASA
The Western Antarctic Ice Sheet is a marine-based ice sheet below sea level that is bounded by the Ronne and Ross Ice Shelf and contains glaciers that drain into the Amundsen Sea. The study announced today incorporates 40 years of data citing multiple lines of observational evidence measuring movement and thickness of Antarctic ice sheets. A key factor to this loss is a thinning along the grounding line of the glaciers from underneath. The grounding line for an ice sheet is the crucial boundary where ice becomes detached from ground underneath and stretches out to become free floating. A slow degradation of the Western Antarctic Ice Sheet has been observed, one that can be attributed to increased stratospheric circulation along with the advection of ocean heat coupled with anthropogenic global warming.
A closeup of the region: red indicates regions where flow speeds have accelerated in the past 40 years. Credit: Eric Rignot
“This sector will be a major contributor to sea level rise in the decades and centuries to come,” Rignot said in today’s press release. “A conservative estimate is it would take several centuries for all of the ice to flow into the sea.”
Thickness contributes to the driving stress of a glacier. Accelerating flow speeds stretch these glaciers out, reducing their weight and lifting them off of the bedrock below in a continuous feedback process.
A key concern for years has been the possible collapse of western Antarctica’s glaciers, leading to a drastic acceleration in sea-level rise worldwide. Such a catastrophic glacial retreat would dump millions of tons of ice into the sea over a relatively short span of time. And while it’s true that ice calves off of the Western Antarctic ice sheet every summer, the annual overall rate is increasing.
The study is backed up by satellite, airborne and ground observations looking at thickness of ice layers over decades.
Researchers stated that the Amundsen Sea Embayment sector alone contains enough ice to increase global sea level by 1.2 metres. A strengthening of wind circulation around the South Pole region since the 1980s has accelerated this process, along with the loss of ozone. This circulation also makes the process more complex than similar types of ice loss seen in Greenland in the Arctic.
The research paper, titled Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011 has been accepted for publication in the American Geophysical Union’s journal Geophysical Research Letters. The American Association for the Advancement of Science will also be releasing a related study on the instability of the West Antarctic ice sheet today in the journal Science.
The most spectacular retreat referenced in the study was seen occurring at the Smith/Kohler glaciers, which migrated about 35 kilometres and became ungrounded over a 500 kilometre square region during the span of 1992 to 2011.
Another telling factor cited in the study was the large scale synchronous ungrounding of several glaciers, suggesting a common trigger mechanism — such as ocean heat flux — is at play.
On the ice shelf proper, the key points that anchor or pin the glaciers to the bedrock below are swiftly vanishing, further destabilizing the ice in the region.
Assets that were used in the study included interferometry data from the Earth Remote Sensing (ERS-1/2) satellites’ InSAR (Interferormetry Synthetic Aperture Radar) instruments, ground team observations and data collected from NASA’s Operation IceBridge overflights of the Antarctic. IceBridge uses a converted U.S. Navy P-3 Orion submarine hunting aircraft equipped with radar experiment packages used to take measurements of the thickness of the ice sheet.
Possible follow up studies targeting the region are upcoming, including five Earth science and observation missions scheduled to be launched this year, which include the Soil Moisture and Passive (SMAP) mission, The Orbiting Carbon Observatory (OCO-2) and the Global Precipitation Measurement (GPM) Core Observatory, launched this past February.
Along with these future NASA missions, there are also two missions — RapidScat and the Cloud-Aerosol Transport System or CATS — slated to study climate headed for the International Space Station this year.
This comes as recent United Nations and United States reports have also announced the reality of climate change and anthropogenic global warming.
“The collapse of this sector of West Antarctica appears to be unstoppable,” Rignot said. “The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers.”
Of course, the solar cycle, volcanic activity, global dimming (via changes in reflectivity, known as albedo) and human activity all play a role in the riddle that is climate change. The bad news is, taking only natural factors into account, we should be in a cooling period right now.
And yes, reflective ice cover also plays a role in the albedo of the Earth, but researchers told Universe Today that no significant overall seasonal variations in the extent of surface layer of ice will change, as the key loss comes from the ungrounding of ice from below. Thus, this ice loss does not present a significant contribution to changes in overall global albedo, though of course, much of this additional moisture will eventually be available for circulation in the atmosphere. And the same was noted in the press conference for those pinning their hopes on the 2014 ice extent being greater than previous years, a season that was a mere blip on the overall trend. The change and retreat in the grounding line below seen in the study was irrespective of the ice extent above.
NASA’s Operation IceBridge will continue to monitor the ice flow when the next Antarctic deployment cycle resumes in October of this year.
And in the meantime, the true discussion is turning to the challenges of living with a warmer planet. Insurance companies, the Department of Defense and residents of low-lying coastal regions such as Miami’s South Beach already know that the reality of global warming and sea level rise is here. Perhaps the very fact that naysayers have at least backed up their positions a bit in recent years from “global warming isn’t happening” to “Its happening, but there are natural cycles” can at least give us a starting point for true intelligent science-based dialogue to begin.
– Social media questions from today’s conference can be reviewed at the #AskNASA hastag.
Simulation of the moon closing in on Saturn just prior to occultation. Credit: Gianluca Masi using SkyX software
Funny thing. Skywatchers are often just as excited to watch a celestial object disappear as we are to see it make an appearance. Early Wednesday morning (May 14) the Full Flower Moon will slip in front of Saturn, covering it from view for about an hour for observers in Australia and New Zealand. If you don’t live where the dingoes roam, no worries. You can watch it online.And no matter where you are on the planet, the big moon will accompany the ringed planet across the sky this Tues. night-Weds. morning.
Moon-Saturn occultation from Perth, Australia Feb. 22, 2014 captured by Colin Legg
Occultations of stars happen swiftly. The moon’s limb meets the pinpoint star and bam! it’s gone in a flash. But Saturn is an extended object and the moon needs time to cover one end of the rings to the other. Planetary occultations afford the opportunity to remove yourself from planet Earth and watch a planet ‘set’ and ‘rise’ over the alien lunar landscape. Like seeing a Chesley Bonestell painting in the flesh.
Saturn and the moon Tuesday night (May 13) just before midnight as viewed from the U.S. Stellarium
As the moon approaches Saturn, the planet first touches the lunar limb and then appears to ‘set’ as it’s covered by degrees. About an hour later, the planet ‘rises’ from the opposite limb. Planetary occultations are infrequent and always worth the effort to see.
Seen from the northern hemisphere and equatorial regions, the nearly full moon will appear several degrees to the right or west of Saturn tomorrow night (May 13). As the night deepens and the moon rolls westward, the two grow closer and closer. They’ll be only a degree apart (two full moon diameters) during Wednesday morning twilight seen from the West Coast. Northern hemisphere viewers will notice that the moon slides to the south of the planet overnight.
Map showing the region where the occultation of Saturn will be visible. Click to get times of Saturn’s disappearance and reappearance for individual cities. Times shown are UT or Universal Time. Add 9.5 hours for Australian Central Standard Time. Credit: IOTA
Skywatchers in Australia will see the moon cover Saturn during convenient early evening viewing hours May 14:
* 8:09 p.m. local time from Adelaide
* 9:05 p.m. Brisbane
* 8:50 p.m. Melbourne
* 8:53 p.m. Canberra
* 8:56 p.m. from Sydney (More times and a map – click HERE)
Before the occultation, Saturn will shine close to the moon’s upper right and might be tricky to see with the naked eye because of glare.
Binoculars will easily reveal the planet, but a telescope is the instrument of choice. Even a small scope magnifying at least 30x will show Saturn and its rings hovering above the bright edge of the moon. Stick around. About an hour later, Saturn will re-emerge along the moon’s lower left limb.
Saturn and its moons Tuesday night May 13 around 10 p.m. CDT. Titan’s the brightest and easiest moon to see at magnitude +8.5. Iapetus ranges from magnitude +10 when it’s west of Saturn and we see its bright hemisphere to magnitude +12 when it’s east of the planet. Created with Meridian software
Meanwhile, back in the western hemisphere, we’ll watch the nearly full Flower Moon make a close pass of the planet. If you’ve had difficulty finding the celestial ring bearer, you’ll have no problem Tuesday night. Take a look at Saturn’s wonderful system of rings in your telescope – they’re tipped nearly wide open this year. For even more fun, see how many moons you can spot. And don’t forget, you can watch it online courtesy of astrophysicist Gianluca Masi. His Virtual Telescope website will broadcast the occultation live starting at 10:15 Universal Time May 14 (6:15 a.m. EDT, 5:15 CDT, 4:15 MDT and 3:15 PDT).
Artist's conception of a hyperveloctiy star heading out from a spiral galaxy (similar to the Milky Way) and moving into dark matter nearby. Credit: Ben Bromley, University of Utah
Zoom! A star was recently spotted speeding at 1.4 million miles an hour (2.2 million km/hr), which happened to be the closest and second-brightest of the so-called “hypervelocity” stars found so far.
Now that about 20 of these objects have been found, however, astronomers are now trying to use the stars beyond classifying them. One of those ways could be probing the nature of dark matter, the mysterious substance thought to bind together much of the universe.
LAMOST-HVS1 (as the object is called, after the Chinese Large Sky Area Multi-Object Fiber Spectroscopic Telescope that discovered it) is about three times faster than most other stars found. It’s in a cluster of similar hypervelocity stars above the Milky Way’s disk and from its motion, scientists suspect it actually came from our galaxy’s center.
What’s interesting about the star, besides its pure speed, is it is travelling in a “dark matter” halo surrounding our galaxies, the astronomers said.
The Milky Way is a spiral galaxy with several prominent arms containing stellar nurseries swathed in pink clouds of hydrogen gas. The sun is shown near the bottom in the Orion Spur. Credit: NASA
“The hypervelocity star tells us a lot about our galaxy – especially its center and the dark matter halo,” stated Zheng Zheng, an astronomy researcher at the University of Utah who led the study.
“We can’t see the dark matter halo, but its gravity acts on the star. We gain insight from the star’s trajectory and velocity, which are affected by gravity from different parts of our galaxy.”
The star is about 62,000 light years from the galaxy’s center (much further than the sun’s 26,000 light years) and is about four times hotter and 3,400 times brighter than our own sun. Astronomers estimate it is 32 million years old, which makes it quite young compared to the sun’s 4.5 billion years.
Image of a hypervelocity star found in data from the Sloan Digital Sky Survey. Image via Vanderbilt University.
Readers of Universe Today may also recall a “runaway star cluster” announced a few weeks ago, which shows you that the universe is replete with speeding objects.
“If you’re looking at a herd of cows, and one starts going 60 mph, that’s telling you something important,” stated Ben Bromley, a fellow university professor who was not involved with Zheng’s study. “You may not know at first what that is. But for hypervelocity stars, one of their mysteries is where they come from – and the massive black hole in our galaxy is implicated.”
The study was recently published in Astrophysical Journal Letters.
Artist's conception of Mars, with asteroids nearby. Credit: NASA
Here’s a finding to give planetary protectionists pause: two species of spores mounted on the International Space Station’s hull a few years back showed a high survival rate after 18 months in space.
Providing that they are shielded against solar radiation, it appears the spores are quite hardy and could easily transport on a spacecraft headed for Mars — which is concerning since so many scientific investigations there these days are focused on habitability of Martian life (whether past or present). The experiment was published in 2012, but highlighted in a recent NASA press release about planetary protection.
The experiment was called PROTECT (an acronym of Resistance of spacecraft isolates to outer space for planetary protection purposes) and studied spores of Bacillus subtilis 168 and Bacillus pumilus SAFR-032. B. pumilus spores were found in an air lock between a “clean room” and entrance floor at NASA’s Jet Propulsion Laboratory, and in previous studies were shown to be more resistant to UV radiation and hydrogen peroxide than “wild” strains. B. subtilis is a spore that has been studied in other space environment experiments.
Samples of both spores were mounted on the EXPOSE-E facility on the space station, which provides up to two years of space exposure. The major goal of this European Space Agency experiment is to study “the origin, evolution and distribution of life in the universe,” NASA states, adding that anything mounted outside of there has to survive “cosmic radiation, vacuum, full-spectrum solar light including UV-C, freezing/thawing cycles [and] microgravity.”
The European Technology Exposure Facility (EuTEF) attached to the Columbus module of the International Space Station. Credit: DLR, Institute of Aerospace Medicine/Dr. Gerda Horneck
The experiment found that if the spores were in areas replete with solar UV radiation, most of them were killed. If those rays were filtered out, however, the spores showed a 50 percent survival rate on both space and simulated “Mars” conditions. It is most concerning to scientists when considering a situation where spores could be hiding underneath each other during a spacecraft trip. The ones on the outside would likely die, but the ones on the inside — shielded from solar radiation — could make it there.
One key limitation in this study, however, is that only two types of spores were studied. This does present a case for doing more studies on this matter in the future, however. Space agencies are quite aware of the problem of planetary protection, as evidenced by departments such as NASA’s Office of Planetary Protection and ESA’s Planetary Protection Officer.
Spacecraft designers constantly make decisions to keep the extraterrestrial bodies we study as safe from Earth contamination as possible; one famous example was when the Galileo probe was deliberately sent into Jupiter in 2003 to protect Europa and other potentially life-bearing moons of the giant planet from possible contamination.
Images of Bacillus pumilus SAFR-032 spores (seen in an electron micrograph) on aluminum before and after being exposed to space on an International Space Station experiment. Credit: P. Vaishampayan, et al./Astrobiology
The rock study (led by Tuscia University’s Silvano Onofri) takes the question of the spores in a different direction, which is examining the phenomenon of “lithopanspermia” — how organisms might move between planets (say, on a meteor). Since Mars meteorites have been found on Earth, some researchers have wondered if life could have spread between our two planets. If that were to happen, the researchers cautioned, the spores would have to survive for thousands or millions of years.
The other B. pumilus paper (led by NASA’s Parag A. Vaishampayan) noted that those spores mounted outside of the space station that survived, showed higher concentrations of proteins that could be linked to resisting UV radiation.
Location chart for HD 162826, considered a sibling to the sun. Credit: Ivan Ramirez/Tim Jones/McDonald Observatory
Peer about 110 light-years away from our solar system, and you might catch a glimpse of how our own neighborhood came together. The recent discovery that HD 162826 — a star bright enough to be seen in binoculars — could be a “sibling” of our sun could shed more light on the solar system’s formation, astronomers said.
“We want to know where we were born,” stated Ivan Ramirez, an astronomer at the University of Texas at Austin who led the research. “If we can figure out in what part of the galaxy the sun formed, we can constrain conditions on the early solar system. That could help us understand why we are here.”
The star is called a “sibling” because it could have formed from the same gas and dust cloud in which our own solar system was formed, some 4.5 billion years ago. Since life is in our own solar system, a natural next question is whether HD 162826 could also have life-bearing planets. There is a tiny reason for “yes”, the astronomers said.
Basically, the argument goes that when the stars were first born and close together, chunks of matter could have been knocked off protoplanets and travelled between the two solar systems. There’s a small chance that this could have brought primitive life to Earth, although of course there’s a long way to go before that could even be proved.
This artist’s conception shows a newly formed star surrounded by a swirling protoplanetary disk of dust and gas. Credit: University of Copenhagen/Lars Buchhave
That said, no planets have yet been found around HD 162826. (The star was known before, but just recently identified as a “sibling.”) Separate studies by the University of Texas and University of South Wales said there are likely no “hot Jupiters” (Jupiter-sized planets close to the star) nor Jupiter-sized planet in the solar system even further away. Smaller terrestrial planets, however, would have escaped the notice of this particular study.
The star is about 15 percent more massive than our sun and was selected from a list of 30 candidates based on its chemistry and orbit. There could also be more siblings out there to find, with one potential big help coming soon: the Gaia survey from the European Space Agency launched in December, which will chart the Milky Way in three dimensions.
Because Gaia will showcase the distance and motions of a billion stars, this will allow astronomers to look for these “solar siblings” as far in as the galaxy’s center, increasing the number of stars studied by a factor of 10,000. The exciting thing, the astronomers add, is with enough stars pinpointed as siblings to our sun, their orbits can then be traced back to the origin point — showing the location in the cosmos where the sun first came to be.
More information will be available in the June 1 issue of the Astrophysical Journal. A preprint version is available on Arxiv.
