The Large Magellanic Cloud is one of the closest galaxies to our own. Astronomers have now used the power of the ESO’s Very Large Telescope to explore NGC 2035, one of its lesser known regions, in great detail. This new image shows clouds of gas and dust where hot new stars are being born and are sculpting their surroundings into odd shapes. But the image also shows the effects of stellar death — filaments created by a supernova explosion (left). Credit: ESO
Some 160,000 light years away towards the constellation of Dorado (the Swordfish), is an amazing area of starbirth and death. Located in our celestial neighbor, the Large Magellanic Cloud, this huge stellar forge sculpts vast clouds of gas and dust into hot, new stars and carves out ribbons and curls of nebulae. However, in this image taken by ESO’s Very Large Telescope, there’s more. Stellar annihilation also awaits and shows itself as bright fibers left over from a supernova event.
For southern hemisphere observers, one of our nearest galactic neighbors, the Large Magellanic Cloud, is a well-known sight and holds many cosmic wonders. While the image highlights just a very small region, try to grasp the sheer size of what you are looking at. The fiery forge you see is several hundred light years across, and the factory in which it is contained spans 14,000 light years. Enormous? Yes. But compared to the Milky Way, it’s ten times smaller.
Even at such a great distance, the human eye can see many bright regions where new stars are actively forming, such as the Tarantula Nebula. This new image, taken by ESO’s Very Large Telescope at the Paranal Observatory in Chile, explores an area cataloged as NGC 2035 (right), sometimes nicknamed the Dragon’s Head Nebula. But, just what are we looking at?
The Dragon’s Head is an HII region, more commonly referred to as an emission nebula. Here, young stars pour forth energetic radiation and illuminate the surrounding clouds. The radiation tears electrons away from the atoms contained within the gas. These atoms then gel again with other atoms and release light. Swirling in the mix is dark dust, which absorbs the light and creates deep shadows and create contrast in the nebula’s structure.
However, as we look deep into this image, there’s even more… a fiery finale. At the left of the photo you’ll see the results of one of the most violent events in the Universe – a supernova explosion. These troubled tendrils are all that’s left of what once was a star and its name is SNR 0536-67.6. Perhaps when it exploded, it was so bright that it was capable of outshining the Magellanic Cloud… fading away over the weeks or months that followed. However, it left a lasting impression!
ISON: A 2013 pre-perihelion portrait. (Credit and copyright: Efrain Morales/Jaicoa observatory. Used with permission).
“ISON Lives!!!”
“ISON R.I.P…”
Those are just some of the possible headlines that we’ve wrestled with this week, as Comet C/2012 S1 ISON approaches perihelion tomorrow evening. It’s been a rollercoaster ride of a week, and this sungrazing comet promises to keep us guessing right up until the very end.
Comet ISON reaches perihelion on U.S. Thanksgiving Day Thursday, November 28th at around 18:44 Universal Time/ 1:44 PM Eastern Standard Time. ISON will pass 1.2 million kilometres from the surface of the Sun, just over eight times farther than Comet C/2011 W3 Lovejoy did in 2011, and about 38 times closer to the Sun than Mercury reaches at perihelion.
Comet ISON as seen from Ottawa, Canada on the morning of November 20th. (Credit: Andrew Symes/@FailedProtostar).
Earth-based observers essentially lost sight of ISON in the dawn twilight this past weekend, and there were fears that the comet might’ve disintegrated all together as it was tracked by NASA’s STEREO spacecraft. Troubling reports circulated early this week that emission rates for the comet had dropped while dust production had risen, possibly signaling that fragmentation of the nucleus was imminent. Certainly, this comet is full of surprises, and our observational experience with large sungrazing comets of this sort is pretty meager.
ISON (entering frame, to the right) currently “photobombing” SOHO’s LASCO C3 camera. Credit: NASA/ESA/SOHO.
However, as ISON entered the field of view of the Solar and Heliospheric Observatory’s LASCO C3 camera earlier today it still appeared to have some game left in it. NASA’s Solar Dynamics Observatory will pick up ISON starting at around 17:09UT/12:09 PM EST tomorrow, and track it through its history-making perihelion passage for just over two hours until 19:09UT/2:19PM EST.
And just as with Comet Lovejoy a few years ago, all eyes will be glued to the webcast from NASA’s Solar Dynamics Observatory as ISON rounds the bend towards its date with destiny… don’t miss it!
Note: you can also follow ISON’s current progress as seen from SOHO at their website!
The tracking plan for the Solar Dynamics Observatory on November 28th as ISON passes through perihelion. (Credit: NASA/SDO).
For over the past year since its discovery, pundits have pondered what is now the astronomical question of the approaching hour: just what is ISON going to do post-perihelion? Will it dazzle or fizzle? In this context, ISON has truly become “Schrödinger’s Comet,” both alive and dead in the minds of those who would attempt to divine its fate.
Recent estimates place ISON’s nucleus at between 950 and 1,250 metres in diameter. This is well above the 200 metre size that’s considered the “point of no return” for a comet passing this close to the Sun. But again, another key factor to consider is how well put together the nucleus of the comet is: a lumpy rubble pile may not hold up against the intense heat and the gravitational tug of the Sun!
Current updated light curve for ISON. Be sure to check with NASA’s Comet ISON Observing Campaign for the latest updates. (Compiled by Matthew Knight on November 24th, 2013).
But what are the current prospects for spotting ISON after its fiery perihelion passage?
If the comet holds together, reasonable estimates put its maximum brightness near perihelion at between magnitudes -3 and -5, in the range of the planet Venus at maximum brilliancy. ISON will, however, only stand 14’ arc minutes from the disk of the Sun (less than half its apparent diameter) at perihelion, and spying it will be a tough feat that should only be attempted by advanced observers.
Note that for observers based at high northern latitudes “north of the 60,” the shallow angle of the ecliptic might just make it possible to spot Comet ISON low in the dawn after perihelion and before sunrise November 29th:
ISON post-perihelion at sunrise on November 29th as seen from Fairbanks, Alaska. (Created using Starry Night Education software.
We’ve managed to see the planet Venus the day of solar conjunction during similar circumstances with the Sun just below the horizon while observing from North Pole, Alaska.
Most northern hemisphere observers may catch first sight of Comet ISON post-perihelion around the morning of December 1st. Look low to the east, about half an hour before local sunrise. Use binoculars to sweep back and forth on your morning comet dawn patrol. Note that on December 1st, Saturn, Mercury, and the slim waning crescent Moon will also perch nearby!
Comet ISON, Mercury, Saturn and the Moon: looking east on the morning of December 1st as seen from latitude 30 degrees north. (Created using Starry Night Education software).
Comet ISON will rapidly gain elevation on successive mornings as it heads off to the northeast, but will also rapidly decrease in brightness as well. If current projections hold, ISON will dip back below magnitude 0 just a few days after perihelion, and back below naked eye visibility by late December. Observers may also be able to start picking it up low to the west at dusk by mid-December, but mornings will be your best bet.
The path of comet ISON for the first week of December as seen from latitude 30 degrees north. Note: the planets and the Moon are depicted for December 1st. (Created using Stellarium).
Keep in mind, if ISON fizzles, this could become a “death-watch” for the remnants of the comet, as fragments that might only be visible with binoculars or a telescope follow its outward path. If this turns out to be the case, then the best views of the “Comet formerly known as ISON” have already occurred.
Another possible scenario is that the comet might fragment right around perihelion, leaving us with a brief but brilliant “headless comet,” similar to W3 Lovejoy back in late 2011. The forward light scattering angle for any comet is key to visibility, and in this aspect, ISON is just on the grim edge in terms of its potential to enter the annals of “great” comets, such as Comet Ikeya-Seki back in 1965.
ISON will then run nearly parallel to the 16 hour line in right ascension from south to north through the month of December as it crosses the celestial equator, headed for a date with the north celestial pole just past New Years Day, 2014.
Whether as fragments or whole, comets have to obey Sir Isaac and his laws of physics as they trace their elliptical path back out of the solar system. Keep in mind, a comet’s dust tail actually precedes it on its way outbound as the solar wind sweeps past, a counter-intuitive but neat concept we may just get to see in action soon.
Here are some key dates to watch for as ISON makes tracks across the northern hemisphere sky. Passages are noted near stars brighter than +5th magnitude and closer than one degree except as mentioned:
The celestial path of ISON from November 29th to December 15th. (Credit: Starry Night).
December 1st: ISON is grouped with Saturn, Mercury and the slim crescent Moon in the dawn.
December 2nd: Passes near the +4.9 magnitude star Psi Scorpii.
December 3rd: Passes into the constellation Ophiuchus.
December 5th: Passes near the +2.7 magnitude multiple star Yed Prior.
December 6th: Crosses into the constellation Serpens Caput.
December 8th: Crosses from south to north of the celestial equator.
December 15th: Passes into the constellation Hercules and near the +5th magnitude star Kappa Herculis.
December 17th: The Moon reaches Full, marking the middle of a week with decreased visibility for the comet.
December 19th: Passes into the constellation of Corona Borealis.
December 20th: Passes near the +4.8th magnitude star Xi Coronae Borealis.
December 22nd: Passes 5 degrees from the globular cluster M13. Photo op!
The path of Comet ISON from December 16th to January 8th. (Credit: Starry Night).
December 23rd: Crosses back into the constellation Hercules.
December 24th: Passes near the +3.9 magnitude star Tau Herculis.
December 26th: Comet ISON passes closest to Earth at 0.43 A.U. or 64 million kilometres distant, now moving with a maximum apparent motion of nearly 4 degrees a day.
December 26th: Crosses into the constellation Draco and becomes circumpolar for observers based at latitude 40 north.
December 28th: Passes the +2.7 magnitude star Aldhibain.
December 29th: Passes the +4.8 magnitude star 18 Draconis.
December 31st: Passes the 4.9 magnitude star 15 Draconis.
January 2nd: Crosses into the constellation Ursa Minor.
January 4th: Crosses briefly back into the constellation Draco.
January 6th: Crosses back into the constellation Ursa Minor.
January 7th: Crosses into Cepheus; passes within 2.5 degrees of Polaris and the North Celestial Pole.
And after what is (hopefully) a brilliant show, ISON will head back out into the depths of the solar system, perhaps never to return. Whatever the case turns out to be, observations of ISON will have produced some first-rate science… and no planets, popes or prophets will have been harmed in the process. And while those in the business of predicting doom will have moved on to the next apocalypse in 2014, the rest of us will have hopefully witnessed a dazzling spectacle from this icy Oort Cloud visitor, as we await the appearance of the next Great Comet.
Enjoy the show!
ISON: “Great Comet” or “Great Pumpkin?” Photo and gourd-based artwork by author.
Artist's impression of the Milky Way, looking at it edge on. This makes the bulge at the center look like a peanut, astronomers say. Credit: ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt.
Remember that 3-D map of the Milky Way that postulated that the center of the galaxy is shaped like a box or peanut? A new math model of the bulge shows that stars in the center of that bulge move in figure-eight orbits (which can also be interpreted as a peanut-shell shape.) Before, previous studies suggested these orbits looked more like bananas.
“The difference is important; astronomers develop theories of star motions to not only understand how the stars in our galaxy are moving today but also how our galaxy formed and evolves,” the Royal Astronomical Society stated.
In the middle of the galaxy, there are a lot of gravitational forces at play due to the sheer number of stars, as well as particles of dust and dark matter, congregating in the area. This makes it harder to model orbits than in more simple situations, such as our own solar system.
This is how a new model envisions it working:
Milky Way. Image credit: NASA
“As the stars go round in their orbits, they also move above or below the plane of the bar. When stars cross the plane they get a little push, like a child on a swing,” the RAS said.
“At the resonance point, which is a point a certain distance from the center of the bar, the timing of the pushes on the stars is such that this effect is strong enough to make the stars at this point move up higher above the plane. (It is like when a child on the swing has been pushed a little every time and eventually is swinging higher.) These stars are pushed out from the edge of the bulge.”
The researchers suppose that the stars would have two “vertical oscillations” in each orbit, but in between the orbits are shaped somewhat like a peanut shell. This “could give rise to the observed shape of the bulge, which is also like a peanut-shell,” RAS stated.
Infographic showing how the Kepler space telescope could continue searching for planets despite two busted reaction wheels. Credit: NASA Ames/W Stenzel
The planet-seeking Kepler space telescope had to stop its primary mission this summer after the failure of a second of its four reaction wheels, the devices that keep it pointing at a spot in the constellation Cygnus. NASA, however, has a backup plan. It’s considering stabilizing the spacecraft using the sun! You can see the details in this infographic.
The plan is still preliminary as it needs testing, and it also needs budgetary approval while NASA is fighting to keep other programs going at the funding levels the agency wants. But if it works, this is what NASA is proposing:
Keep the spacecraft oriented almost parallel to its orbit around the sun.
Gaze at a particular part of the sky for 83 days.
When the sun is close to coming into the telescope, move the spacecraft and do another 83-day observation period.
This would mean the spacecraft will have 4.5 “unique viewing periods” a year, NASA says.
“With the failure of a second reaction wheel, the spacecraft can no longer precisely point at the mission’s original field of view. The culprit is none other than our own sun,” NASA stated in a recent press release.
Artist’s conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech
“The very body that provides Kepler with its energy needs also pushes the spacecraft around by the pressure exerted when the photons of sunlight strike the spacecraft. Without a third wheel to help counteract the solar pressure, the spacecraft’s ultra-precise pointing capability cannot be controlled in all directions.”
But this could be a way to counteract it. Mission managers put Kepler through a 30-minute test in October where the telescope looked at a spot in the constellation Sagittarius, which “produced an image quality within five percent of the primary mission image quality,” NASA stated. More testing is underway.
NASA should have more details at the end of this year as to whether to proceed to a 2014 Senior Review, which is held every two years to review current missions and decide which ones are still worth funding.
NASA astronaut Rick Mastracchio inspects a spacesuit during repairs in the Quest airlock aboard the International Space Station. Taken during Expedition 38 in November 2013. Credit: NASA
Judging from the way those food packets are floating around, looks like the folks on the International Space Station will have to catch their turkey! NASA astronauts Rick Mastracchio and Mike Hopkins, two of the six people working on Expedition 38, recently shared their plans for U.S. Thanksgiving on Thursday.
“Though we miss our families, it’s great to be in space. As astronauts, this is what we train for and this is where we want to be. Opportunities to fly in space are rare, so we have to take advantage of them whenever they occur,” Hopkins said in the message.
The best part of this missive? Watching the astronauts casually toss the microphone back and forth in between their statements. That’s the fun of recording in microgravity.
Thanksgiving will be a full workday on station as the astronauts continue to work on their experiments. A recent status report indicated that Mastracchio (the crew medical officer) was examining Hopkins’ eyes as part of ongoing work looking at how microgravity affects ocular health. Flight controllers also moved one of the solar arrays for Mastracchio to take pictures and monitor how the mast is doing “for future inspections”, NASA stated.
A comparison between our solar system and a second solar system: KOI-351. Image Credit:
A team of European astronomers has discovered a second planetary system, the closest parallel to our own solar system yet found. It includes seven exoplanets orbiting a star with the small rocky planets close to their host star and the gas giant planets further away. The system was hidden within the wealth of data from the Kepler Space Telescope.
KOI-351 is “the first system with a significant number of planets (not just two or three, where random fluctuations can play a role) that shows a clear hierarchy like the solar system — with small, probably rocky, planets in the interior and gas giants in the (exterior),” Dr. Juan Cabrera, of the Institute of Planetary Research at the German Aerospace Center, told Universe Today.
Three of the seven planets orbiting KOI-351 were detected earlier this year, and have periods of 59, 210 and 331 days — similar to the periods of Mercury, Venus and Earth.
But the orbital periods of these planets vary by as much as 25.7 hours. This is the highest variation detected in an exoplanet’s orbital period so far, hinting that there are more planets than meets the eye.
In closely packed systems, the gravitational pull of nearby planets can cause the acceleration or deceleration of a planet along its orbit. These “tugs” cause the variations in orbital periods.
They also provide indirect evidence of further planets. Using advanced computer algorithms, Cabrera and his team detected four new planets orbiting KOI-351.
But these planets are much closer to their host star than Mercury is to our Sun, with orbital periods of 7, 9, 92 and 125 days. The system is extremely compact — with the outermost planet having an orbital period less than the Earth’s. Yes, the entire system orbits within 1 AU.
While astronomers have discovered over 1000 exoplanets, this is the first solar system analogue detected to date. Not only are there seven planets, but they display the same architecture — rocky small planets orbiting close to the sun and gas giants orbiting further away — as our own solar system.
Most exoplanets are strikingly different from the planets in our own solar system. “We find planets in any order, at any distance, of any size; even planetary classes that don’t exist in the solar system,” Cabrera said.
Several theories including planet migration and planet-planet scattering have been proposed to explain these differences. But the fact of the matter is planet formation is still poorly understood.
“We don’t know yet why this system formed this way, but we have the feeling that this is a key system in understanding planetary formation in general and the formation of the solar system in particular,” Cabrera told Universe Today.
The team is extremely hopeful that the upcoming mission PLATO will receive funding. If so, it will allow them to take a second look at this system — determining the radius and mass of each planet and even analyzing their compositions.
Follow-up observations will not only allow astronomers to determine how this planetary system formed, it will provide hints as to how our own solar system formed.
The paper has been accepted for publication in the Astrophysical Journal and is available for download here.
Earlier today the near-Earth asteroid 2013 NJ sailed by, coming as close as 2.5 lunar distances — about 960,000 km/596,500 miles. That’s a relatively close call, in astronomical terms, but still decidedly a miss (if you hadn’t already noticed.) Which is a good thing since 2013 NJ is estimated to be anywhere from 120–260 meters wide (400-850 feet) and would have caused no small amount of damage had its path intersected ours more intimately.
Luckily that wasn’t the case, and instead we get watch 2013 NJ as it harmlessly passes by in the video above, made from images captured by “shadow chaser” Jonathan Bradshaw from his observatory in Queensland, Australia. Nice work, Jonathan!
Keep tabs on known near-Earth objects on the JPL close pass page here.
An annotated version of a deep-sky wide field view of our own galaxy, the Milky Way. Credit and copyright: Miguel Claro.
This new panorama of the Milky Way by astrophotographer Miguel Claro is really amazing, and you definitely want to click on the image to have access to larger versions! This is an 18-image mosaic taken with a Canon 60Da, with 60 second exposures, and it rivals wide-field images taken by larger ground-based telescopes. The images, were, however, taken from the home of some of the darkest skies and largest telescopes in the world, near Roque de Los Muchahos, in La Palma, Canary Islands. Visible is the hazy band of white light that comes from unresolved stars and other material that lie within the galactic plane, contrasting with interesting shapes within the dark regions of the band, corresponding to areas where light from distant stars is blocked by interstellar dust.
Thanks to Miguel Claro for sharing his images with Universe Today!
The Milky Way Galaxy – Deep Sky Wide Field view, captured from Los Andenes, near Roque de Los Muchahos, in La Palma, Canary Island. Credit and copyright: Miguel Claro.
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Gamma-ray pulsars in the Milky Way's plane, found by volunteers using Einstein@Home. The sky map is from Fermi's Large Area Telescope. The brighter the color you see, the more intense the radiation in that spot. The small flags show the nationality of the volunteers whose computers spotted the pulsars. Credit: Knispel/Pletsch/AEI/NASA/DOE/Fermi LAT Collaboration
Imagine that you’re innocently running your computer in pursuit of helping data crunch a huge science project. Then, out of the thousands of machines running the project, yours happens to stumble across a discovery. That’s what happened to several volunteers with Einstein@Home, which seeks pulsars in data from the Fermi Gamma-Ray Space Telescope, among other projects.
“At first I was a bit dumbfounded and thought someone was playing a hoax on me. But after I did some research,” everything checked out. That someone as insignificant as myself could make a difference was amazing,” stated Kentucky resident Thomas M. Jackson, who contributed to the project.
Pulsars, a type of neutron star, are the leftovers of stars that exploded as supernovae. They rotate rapidly, with such precision in their rotation periods that they have sometimes been likened to celestial clocks. Although the discovery is exciting to the eight volunteers because they are the first to find these gamma-ray pulsars as part of a volunteer computing project, the pulsars also have some interesting scientific features.
Artist’s illustration of a neutron star, a tiny remnant that remains after its predecessor star explodes. Here, the 12-mile (20-kilometer) sphere is compared with the size of Hannover, Germany. Credit: NASA’s Goddard Space Flight Center
The four pulsars were discovered in the plane of the Milky Way in an area that radio telescopes had looked at previously, but weren’t able to find themselves. This means that the pulsars are likely only visible in gamma rays, at least from the vantage point of Earth; the objects emit their radiation in a narrow direction with radio, but a wider stripe with gamma rays. (After the discoveries, astronomers used the Max Planck Institute for Radio Astronomy’s 100-meter Effelsberg radio telescope and the Australian Parkes Observatory to peer at those spots in the sky, and still saw no radio signals.)
Two of the pulsars also “hiccup” or exhibit a pulsar glitch, when the rotation sped up and then fell back to the usual rotation period a few weeks later. Astronomers are still learning more about these glitches, but they do know that most of them happen in young pulsars. All four pulsars are likely between 30,000 and 60,000 years old.
Artist’s conception of a gamma-ray pulsar. Gamma rays are shown in purple, and radio radiation in green. Credit: NASA/Fermi/Cruz de Wilde
“The first-time discovery of gamma-ray pulsars by Einstein@Home is a milestone – not only for us but also for our project volunteers. It shows that everyone with a computer can contribute to cutting-edge science and make astronomical discoveries,” stated co-author Bruce Allen, principal investigator of Einstein@Home. “I’m hoping that our enthusiasm will inspire more people to help us with making further discoveries.”
Einstein@Home is run jointly by the Center for Gravitation and Cosmology at the University of Wisconsin–Milwaukee and the Albert Einstein Institute in Hannover, Germany. It is funded by the National Science Foundation and the Max Planck Society. As for the volunteers, their names were mentioned in the scientific literature and they also received certificates of discovery for their work.
Artist's conception of ESA's OTS-2 telecom satellite, which was retired from geostationary orbit in 1991 after nearly 13 years of service. Credit: ESA
Space junk is an ongoing concern for NASA, the European Space Agency and many others. After satellites live out their useful lives in orbit, more and more the agencies are trying to either move them far away from Earth, or to have the satellites burn up in the atmosphere. That’s basically to preserve orbital slots around the planet for others, and to reduce the risk of collisions.
But here’s an alternate approach — why not leave a few satellites handy for other missions to pick up? ESA recently opened a tender exploring this idea, and put a few thoughts out in a press release. Maybe leftover solid rocket fuel could be re-used. Metal alloys could be ground down for potential 3-D printing materials. Life support systems could use biodegradable materials. Since it costs so much to haul stuff into orbit, maybe it might be worthwhile to leave some available for future missions, ESA reasons.
Image plot of space junk. Image credit: NASA
“ESA’s new invitation for ‘Sustainable Materials Concepts’ is seeking companies to study various concepts of this approach, including considering the kinds of materials that could be reused as biological or technical nutrients – serving as resources for new other processes,” ESA stated.
“Also under consideration: what sustainable materials might replace current space-grade materials such as titanium and aluminium alloys or carbon-fibre epoxy resins? And how might the use of materials as biological or technical nutrients work in practice?”
What do you think satellites could be used for? Leave your thoughts in the comments.
