Artist's conception of asteroid Bennu from the NASA film "Bennu's Journey." Credit: NASA/YouTube (screenshot)
We’ve been super-excited about the Philae landing recently, the first soft landing on a comet. But imagine if the spacecraft was equipped to bring a sample of Comet 67P/Churyumov–Gerasimenko back to Earth. What sort of secrets could we learn from examining the materials of the comet up close?
That dream will remain a dream for 67P, but guess what — if all goes to plan, that idea will execute for asteroid Bennu. Check out the new video above for more details on the audacious mission; below the jump is a brief mission description.
There is a mission expected to launch in 2016 called OSIRIS-REx that will spend two years flying to the asteroid to nab a sample, then will come back to Earth in 2023 to deliver it to scientists. This is exciting because asteroids are a sort of time capsule showing how the Solar System used to be in the early days, before gravity pulled rocks and ice together to gradually form the planets and moons that we have today.
“Scientists tell us that asteroid Bennu has been a silent witness to titanic events in the solar system’s 4.6 billion year history,” NASA wrote on a website commemorating the new video. “When it returns in 2023 with its precious cargo, OSIRIS-REx will help to break that silence and retrace Bennu’s journey.”
For more information on OSIRIS-REx, check out the mission’s website.
Artist's conception of early planetary formation from gas and dust around a young star. Outbursts from newborn and adolescent stars might drive planetary water beneath the surface of rocky worlds.
Credit: NASA/NASA/JPL-Caltech
This isn’t a clone of our Solar System, but it’s close enough. Scientists eagerly scrutinized a young star system called HD 95086 to learn more about how dust belts and giant planets grow up together. This is an important finding for our own neighborhood, where the gas giants of Jupiter, Saturn, Uranus and Neptune are also wedged between dusty areas.
“By looking at other star systems like these, we can piece together how our own Solar System came to be,” stated lead author Kate Su, an associate astronomer at the University of Arizona, Tucson.
The system is about 295 light-years from Earth, and is suspected to have two dust belts: a warmer one (similar to our asteroid belt) and a cooler one (similar to the Kuiper Belt that has icy objects.) The system is host to at least one planet that is five times the mass of Jupiter, and other planets could also be hiding between the dusty lanes. This planet, called HD 95086 b, was imaged by the European Southern Observatory’s Very Large Observatory in 2013.
Planet HD95086 b is shown at lower left in this picture. Astronomers blocked out the light of the star (center) to image the exoplanet. The blue circle represents the equivalent orbit of Neptune in this star system. Credit: ESO/J. Rameau
The next step was a comparison study with another star system called HR 8799, which also has two dusty rings and in this case, at least four planets in between. These planets have also been caught on camera. Comparing the structure of the two systems indicates that HD 95086 may have more planets lurking for astronomers to discover.
“By knowing where the debris is, plus the properties of the known planet in the system, we can get an idea of what other kinds of planets can be there,” stated Sarah Morrison, a co-author of the paper and a PhD student at the University of Arizona. “We know that we should be looking for multiple planets instead of a single giant planet.”
The researchers presented their work at the Division for Planetary Science Meeting of the American Astronomical Society in Tucson, Arizona. A press release did not disclose publication plans or if the work was peer-reviewed.
This is the sharpest image ever taken by ALMA — sharper than is routinely achieved in visible light with the NASA/ESA Hubble Space Telescope. It shows the protoplanetary disc surrounding the young star HL Tauri. These new ALMA observations reveal substructures within the disc that have never been seen before and even show the possible positions of planets forming in the dark patches within the system. Credit: ALMA (ESO/NAOJ/NRAO)
In a test of its new high resolution capabilities, the Atacama Large Millimeter/submillimeter Array (ALMA) is happily sharing some family snapshots with us. Astronomers manning the cameras have captured one of the best images so far of a newly-forming planet system gathering itself around a recently ignited star. Located about 450 light years from us in the constellation of Taurus, young HL Tau gathers material around it to hatch its planets and fascinate researchers.
Thanks to ALMA images, scientists have been able to witness stages of planetary formation which have been suspected, but never visually confirmed. This very young star is surrounded by several concentric rings of material which have neatly defined spacings. Is it possible these clearly marked gaps in the solar rubble disc could be where planets have started to gel?
“These features are almost certainly the result of young planet-like bodies that are being formed in the disk. This is surprising since HL Tau is no more than a million years old and such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image,” said ALMA Deputy Director Stuartt Corder.
“When we first saw this image we were astounded at the spectacular level of detail. HL Tauri is no more than a million years old, yet already its disc appears to be full of forming planets. This one image alone will revolutionize theories of planet formation,” explained Catherine Vlahakis, ALMA Deputy Program Scientist and Lead Program Scientist for the ALMA Long Baseline Campaign.
Let’s take a look at what we understand about solar system formation…
Through repeated research, astronomers suspect that all stars are created when clouds of dust and gas succumb to gravity and collapse on themselves. As the star begins to evolve, the dust binds together – turning into “solar system soup” consisting of an array of different sized sand and rocks. This rubble eventually congeals into a thin disc surrounding the parent star and becomes home to newly formed asteroids, comets, and planets. As the planets collect material into themselves, their gravity re-shapes to structure of the disc which formed them. Like dragging a lawn sweeper over fallen leaves, these planets clear a path in their orbit and form gaps. Eventually their progress pulls the gas and dust into an even tighter and more clearly defined structure. Now ALMA has shown us what was once only a computer model. Everything we thought we knew about planetary formation is true and ALMA has proven it.
This is the sharpest image ever taken by ALMA — sharper than is routinely achieved in visible light with the NASA/ESA Hubble Space Telescope. It shows the protoplanetary disc surrounding the young star HL Tauri. The observations reveal substructures within the disc that have never been seen before and even show the possible positions of planets forming in the dark patches within the system. In this picture the features seen in the HL Tauri system are labelled. Credit: ALMA (ESO/NAOJ/NRAO)
“This new and unexpected result provides an incredible view of the process of planet formation. Such clarity is essential to understand how our own solar system came to be and how planets form throughout the universe,” said Tony Beasley, director of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, which manages ALMA operations for astronomers in North America.
“Most of what we know about planet formation today is based on theory. Images with this level of detail have up to now been relegated to computer simulations or artist’s impressions. This high resolution image of HL Tauri demonstrates what ALMA can achieve when it operates in its largest configuration and starts a new era in our exploration of the formation of stars and planets,” says Tim de Zeeuw, Director General of ESO.
The major reason astronomers have never seen this type of structure before is easy to envision. The very dust which creates the planetary disc around HL Tau also conceals it to visible light. Thanks to ALMA’s ability to “see” at much longer wavelengths, it can image what’s going on at the very heart of the cloud. “This is truly one of the most remarkable images ever seen at these wavelengths. The level of detail is so exquisite that it’s even more impressive than many optical images. The fact that we can see planets being born will help us understand not only how planets form around other stars but also the origin of our own solar system,” said NRAO astronomer Crystal Brogan.
How does ALMA do it? According to the research staff, its new high-resolution capabilities were achieved by spacing the antennas up to 15 kilometers apart. This baseline at millimeter wavelengths enabled a resolution of 35 milliarcseconds, which is equivalent to a penny as seen from more than 110 kilometers away. “Such a resolution can only be achieved with the long baseline capabilities of ALMA and provides astronomers with new information that is impossible to collect with any other facility, including the best optical observatories,” noted ALMA Director Pierre Cox.
This is a composite image of the young star HL Tauri and its surroundings using data from ALMA (enlarged in box at upper right) and the NASA/ESA Hubble Space Telescope (rest of the picture). This is the first ALMA image where the image sharpness exceeds that normally attained with Hubble. Credit: ALMA (ESO/NAOJ/NRAO)
The long baselines spell success for the ALMA observations and are a tribute to all the technology and engineering that went into its construction. Future observations at ALMA’s longest possible baseline of 16 kilometers will mean even more detailed images – and an opportunity to further expand our knowledge of the Cosmos and its workings. “This observation illustrates the dramatic and important results that come from NSF supporting world-class instrumentation such as ALMA,” said Fleming Crim, the National Science Foundation assistant director for Mathematical and Physical Sciences. “ALMA is delivering on its enormous potential for revealing the distant universe and is playing a unique and transformational role in astronomy.”
Pass them baby pictures our way, Mama ALMA… We’re delighted to take a look!
This wide-field view shows the sky around the young multiple star system GG Tauri, which appears very close to the centre of this picture. This view also shows a dust cloud and evidence of star formation near the top of the picture. Credit: ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin
Deep within the Taurus Dark Cloud complex, one of the closest star-forming regions to Earth has just revealed one of its secrets – an umbilical cord of gas flowing from the expansive outer disc toward the interior of a binary star system known as GG Tau-A. According to the ESO press release, this never-before-seen feature may be responsible for sustaining a second, smaller disc of planet-forming material that otherwise would have disappeared long ago.
A research group led by Anne Dutrey from the Laboratory of Astrophysics of Bordeaux, France and CNRS used the Atacama Large
Millimeter/submillimeter Array (ALMA) to observe the distribution of
dust and gas in the unusual GG Tau-A system. Since at least half of
Sun-like stars are the product of binary star systems, these type of
findings may produce even more fertile grounds for discovering
exoplanets. However, the 450 light year distant GG Tau system is even more complex than previously thought. Through observations taken with the VLTI, astronomers have discovered its primary star – home to the inner disc – is part of a more involved multiple-star system. The secondary star is also a close binary!
“We may be witnessing these types of exoplanetary systems in the midst of formation,” said Jeffrey Bary, an astronomer at Colgate University in Hamilton, N.Y., and co-author of the paper. “In a sense, we are learning why these seemingly strange systems exist.”
Let’s take a look…
This artist’s impression shows the dust and gas around the double star system GG Tauri-A. Researchers using ALMA have detected gas in the region between two discs in this binary system. This may allow planets to form in the gravitationally perturbed environment of the binary. Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets.
“Like a wheel in a wheel, GG Tau-A contains a large, outer disc
encircling the entire system as well as an inner disc around the main central star. This second inner disc has a mass roughly equivalent to that of Jupiter.” says the research team. “Its presence has been an intriguing mystery for astronomers since it is losing material to its central star at a rate that should have depleted it long ago.”
Thanks to studies done with ALMA, the researchers made an exciting discovery in these disc structures… gas clumps located between the two. This observation could mean that material is being fed from the outer disc to feed the inner. Previously observations done with ALMA show that a single star pulls its materials inward from the outer disc. Is it possible these gas pockets in the double disc GG Tau-A system are creating a sustaining lifeline between the two?
“Material flowing through the cavity was predicted by computer
simulations but has not been imaged before. Detecting these clumps
indicates that material is moving between the discs, allowing one to
feed off the other,” explains Dutrey. “These observations demonstrate that material from the outer disc can sustain the inner disc for a long time. This has major consequences for potential planet formation.”
As we know, planets are created from the materials leftover from
stellar ignition. However, the creation of a solar system occurs at a snail’s pace, meaning that a debris disc with longevity is required for planet formation. Thanks to these new “disc feeding” observations from ALMA, researchers can surmise that other multiple-star systems behave in a similar manner… creating even more possibilities for exoplanet formation.
“This means that multiple star systems have a way to form planets, despite their complicated dynamics. Given that we continue to find interesting planetary systems, our observations provide a glimpse of the mechanisms that enable such systems to form,” concludes Bary.
During the initial phase of planetary searches, the emphasis was placed on Sun-like, single-host stars. Later on, binary systems gave rise to giant Jupiter-sized planets – nearly large enough to be stars on their own. Now the focus has turned to pointing our planetary discovery efforts towards individual members of multiple-systems.
Emmanuel Di Folco, co-author of the paper, concludes: “Almost half the Sun-like stars were born in binary systems. This means that we have found a mechanism to sustain planet formation that applies to a significant number of stars in the Milky Way. Our observations are a big step forward in truly understanding planet formation.”
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
This new find is at least times the size of Jupiter and about the equivalent distance of Saturn to our own Sun, which means the planet would not be habitable as far as we can tell. It was spotted using a way of measuring carbon monoxide emission that seems to change its velocity and position in the same way that a planet would be expected to be orbiting the star.
The emission itself could be coming from a disk of gas surrounding the planet, or perhaps from the object’s tidal interactions with the gas and dust enveloping the young star, which is only 335 light-years from Earth.
“This system is very close to Earth relative to other disk systems. We’re able to study it at a level of detail that you can’t do with more distant stars. This is the first system where we’ve been able to do this,” stated Sean Brittain, an associate professor of astronomy and astrophysics at Clemson University in South Carolina.
“Once we really understand what’s going on, the tools that we are developing can then be applied to a larger number of systems that are more distant and harder to see.”
The study was published in the Astrophysical Journal.
An artist's conception of what scientists think was an asteroid collision near star NGC 2547-1D8, which is 1,200 light-years from Earth. An influx of dust was noticed from Earth between August 2012 and 2013. Credit: NASA/JPL-Caltech
When a crop of dust spread forth from the star NGC 2547-1D8 during 2012 observations, scientists quickly sprang into action. What they believe happened was two huge asteroids 1,200 light-years away crashed into each other. What’s more, researchers say that what they witnessed could herald planetary formation similar to what created our own solar system.
“We think two big asteroids crashed into each other, creating a huge cloud of grains the size of very fine sand, which are now smashing themselves into smithereens and slowly leaking away from the star,” stated lead author and graduate student Huan Meng of the University of Arizona.
The debris was tracked with NASA’s Spitzer Space Telescope, and represents the first time scientists have picked up information before and after an event such as this.
Scientists did see dust variability from the system before, which prompted them to put it under close scrutiny — sometimes looking at it every day. The biggest surge took place across five months in 2012. Observations were interrupted because the star was too close to our Sun’s field of view; when it was safe to return, that’s when scientists spotted all the dust.
The Spitzer Space Telescope. Credit: NASA
“We not only witnessed what appears to be the wreckage of a huge smashup, but have been able to track how it is changing — the signal is fading as the cloud destroys itself by grinding its grains down so they escape from the star,” stated Kate Su of the University of Arizona, who is a co-author on the study.
It is believed that planets, moons and other objects in our solar system coalesced over millions of years from collisions such as this. The far-away collision did take place in a spot where planets could form some day, NASA noted, which makes it all the more interesting to scientists.
The crescent moon, Saturn and Mars will form a compact triangle in the southwestern sky in this evening August 31st. 3.5º separate the moon and Saturn; Mars and Saturn will be 5º apart. Stellarium
Check it out. Look southwest at dusk tonight and you’ll see three of the solar system’s coolest personalities gathering for a late dinner. Saturn, Mars and the waxing crescent moon will sup in Libra ahead of the fiery red star Antares in Scorpius. All together, a wonderful display of out-of-this-world worlds.
Four dark lunar seas, also called ‘maria’ (MAH-ree-uh), pop out in binoculars. Four featured craters are also highlighted – the triplet of Theophilus, Cyrillus and Catharina and Maurolycus, named after Francesco Maurolico, a 16th century Italian scientist. Credit: Virtual Moon Atlas / Christian LeGrande, Patrick Chevalley
If you have binoculars, take a closer look at the thick lunar crescent. Several prominent lunar seas, visible to the naked eye as dark patches, show up more clearly and have distinctly different outlines even at minimal magnification. Each is a plain of once-molten lava that oozed from cracks in the moon’s crust after major asteroid strikes 3-3.5 billion years ago.
Larger craters also come into view at 10x including the remarkable trio of Theophilus, Cyrillus and Catharina, each of which spans about 60 miles (96 km) across. Even in 3-inch telescope, you’ll see that Theophilus partly overlaps Cyrillus, a clear indicator that the impact that excavated the crater happened after Cyrillus formed.
Close-up of our featured trio of craters. Sharpness indicates freshness. Comparing the three, the Theophilus impact clearly happened after the others. Craters gradually become eroded over time from micrometeorite impacts, solar wind bombardment, moonquakes and extreme day-to-night temperature changes. Credit: Damian Peach
Notice that the rim Theophilus crater is still relatively crisp and fresh compared to the older, more battered outlines of its neighbors. Yet another sign of its relative youth.
Astronomers count craters on moons and planets to arrive at relative ages of their surfaces. Few craters indicate a youthful landscape, while many overlapping ones point to an ancient terrain little changed since the days when asteroids bombarded all the newly forming planets and moons. Once samples of the moon were returned from the Apollo missions and age-dated, scientists could then assign absolute ages to particular landforms. When it comes to planets like Mars, crater counts are combined with estimates of a landscape’s age along with information about the rate of impact cratering over the history of the solar system. Although we have a number of Martian meteorites with well-determined ages, we don’t know from where on Mars they originated.
At least three different impact sequences are illustrated in this photo. Maurolycus appears to lie atop an older crater, while younger, sharp-rimmed craters pock its center and southern rim. Even a 3-inch telescope will show signs of all three ages. Credit: Damian Peach
Another crater visible in 10x binoculars tonight is Maurolycus (more-oh-LYE-kus), a great depression 71 miles (114 km) across located in the moon’s southern hemisphere in a region rich with overlapping craters. Low-angled sunlight highlighting the crater’s rim will make it pop near the moon’s terminator, the dividing line between lunar day and night.
Like Theophilus, Maurolycus overlaps a more ancient, unnamed crater best seen in a small telescope. Notice that Maurolycus is no spring chicken either; its floor bears the scares of more recent impacts.
Putting it all into context, despite their varying relative ages, most of the moon’s craters are ancient, punched out by asteroid and comet bombardment more than 3.8 billion years ago. To look at the moon is to see a fossil record of a time when the solar system was a terrifyingly untidy place. Asteroids beat down incessantly on the young planets and moons.
Despite the occasional asteroid scare and meteorite fall, we live in relative peace now. Think what early life had to endure to survive to the present. Deep inside, our DNA still connects us to the terror of that time.
Artist's impression of Beta Pictoris b. Credit: ESO L. Calçada/N. Risinger (skysurvey.org)
Between the time you got to work this morning and the time you leave today — assuming an eight-hour work cycle — an entire day will have passed on Beta Pictoris b, according to new measurements of the exoplanet.
This daily cycle, mapped for the first time on a planet outside of the solar system, may reveal a link between how big a planet is and how fast it rotates, astronomers stated. That said, caution is needed because there are only a handful of planets where the rotation is known: the eight planets of our Solar System and Beta Pictoris b.
The planet’s day is shorter than any other planet in our Solar System, which at first blush makes sense because the planet is also larger than any other planet in our Solar System. Beta Pictoris b is estimated at 16 times larger and 3,000 times more massive than Earth. (For comparison, Jupiter is about 11 times larger and 318 times more massive than Earth.)
“It is not known why some planets spin fast and others more slowly,” stated says co-author Remco de Kok, “but this first measurement of an exoplanet’s rotation shows that the trend seen in the Solar System, where the more massive planets spin faster, also holds true for exoplanets. This must be some universal consequence of the way planets form.”
Planets in our Solar system size comparison. Largest to smallest are pictured left to right, top to bottom: Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury. Via Wikimedia Commons.
Astronomers mapped the planet’s equatorial rotation using the CRIRES instrument on the Very Large Telescope. What helped was not only the planet’s large size, but also its proximity to Earth: it’s about 63 light-years away, which is relatively close to us.
As the planet ages (it’s only 20 million years old right now) it is expected to shrink and spin more quickly, assuming no other external forces. The Earth’s rotation is slowed by the moon, for example.
The study (“Fast spin of a young extrasolar planet” will soon be up on Nature’s website and was led by Leiden University’s Ignas Snellen.
Artist's impression of what the rings of the asteroid Chariklo would look like from the small body's surface. The rings' discovery was a first for an asteroid. Credit: ESO/L. Calçada/Nick Risinger (skysurvey.org)
Rings are a tough phenomenon to spot. As late as 1977, astronomers thought that the only thing in the solar system with rings was the planet Saturn. Now, we can add the first asteroid to the list of ringed bodies nearby us. The asteroid 10199 Chariklo hosts two rings, perhaps due to a collision that caused a chain of debris circling its tiny surface.
Besides the 250-kilometer (155-mile) Chariklo, the only other ringed bodies known to us so far are (in order of discovery) Saturn, Uranus, Jupiter and Neptune.
“We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all, so the discovery — and the amazing amount of detail we saw in the system — came as a complete surprise,” stated Felipe Braga-Ribas of the National Observatory (Observatório Nacional) in Brazil, who led the paper about the discovery.
Illustration of how Asteroid Chariklo may have gotten its rings. Copyright: Estevan Guzman for Universe Today.
The rings came to light, so to speak, when astronomers watched Chariklo passing in front of the star UCAC4 248-108672 on June 3, 2013 from seven locations in South America. While watching, they saw two dips in the star’s apparent brightness just before and after the occultation. Better yet, with seven sites watching, researchers could compare the timing to figure out more about the orientation, shape, width and more about the rings.
The observations revealed what is likely a 12.4-mile (20-kilometer)-wide ring system that is about 1,000 times closer to the asteroid than Earth is to the moon. What’s more, astronomers suspect there could be a moon lying amidst the asteroid’s ring debris.
Artist’s impression of two rings discovered around the asteroid Chariklo. It was the first such discovery made for an asteroid. Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)
If these rings are the leftovers of a collision as astronomers suspect, this would give fodder to the idea that moons (such as our own moon) come to be from collisions of smaller bits of material. This is also a theory for how planets came to be around stars.
The rings haven’t been named officially yet, but the astronomers are nicknaming them Oiapoque and Chuí after two rivers near the northern and southern ends of Brazil.
Because these occultation events are so rare and can show us more about asteroids, astronomers pay attention when they occur. Part of the Eastern Seabord enjoyed a more recent asteroid-star occultation on March 20.
The original paper, “A ring system detected around the Centaur (10199) Chariklo”, will soon be available on the Nature website.
Artist’s impression of rings around the asteroid Chariklo. This was the first asteroid where rings were discovered. Credit: ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)
It’s a tough old universe out there. A young star has lots to worry about, as massive stars just beginning to shine can fill a stellar nursery with a gale of solar wind.
No, it’s not a B-movie flick: the “Death Stars of Orion” are real. Such monsters come in the form of young, O-type stars.
And now, for the first time, a team of astronomers from Canada and the United States have caught such stars in the act. The study, published in this month’s edition of The Astrophysical Journal, focused on known protoplanetary disks discovered by the Hubble Space Telescope in the Orion Nebula.
These protoplanetary disks, also known as “tadpoles” or proplyds, are cocoons of dust and gas hosting stars just beginning to shine. Much of this leftover material will go on to aggregate into planets, but nearby massive O-Type stars can cause chaos in a stellar nursery, often disrupting the process.
“O-Type stars, which are really monsters compared to our Sun, emit tremendous amounts of ultraviolet radiation and this can play havoc during the development of young planetary systems,” said astronomer Rita Mann in a recentpress release. Mann works for the National Research Council of Canada in Victoria and is lead researcher on the project
Scientists used the Atacama Large Millimeter Array (ALMA) to probe the proplyds of Orion in unprecedented detail. Supporting observations were also made using the Submillimeter Array in Hawaii.
ALMA saw “first light” in 2011, and has already achieved some first rate results.
“ALMA is the world’s most sensitive telescope at high-frequency radio waves (e.g., 100-1000 GHz). Even with only a fraction of its final number of antennas, (with 22 operational out of a total planned 50) we were able to detect with ALMA the disks relatively close to the O-star while previous observatories were unable to spot them,” James Di Francesco of the National Research Council of Canada told Universe Today. “Since the brightness of a disk at these frequencies is proportional to its mass, these detections meant we could measure the masses of the disks and see for sure that they were abnormally low close to the O-type star.”
The ALMA antennae on the barren plateau of Chajnantor. Credit: ALMA (ESO/NAOJ/NRAO).
ALMA also doubled the number of proplyds seen in the region, and was also able to peer within these cocoons and take direct mass measurements. This revealed mass being stripped away by the ultraviolet wind from the suspect O-type stars. Hubble had been witness to such stripping action previous, but ALMA was able to measure the mass within the disks directly for the first time.
And what was discovered doesn’t bode well for planetary formation. Such protostars within about 0.1 light-years of an O-type star are consigned to have their cocoon of gas and dust stripped clean in just a few million years, just a blink of a eye in the game of planetary formation.
With a O-type star’s “burn brightly and die young” credo, this type of event may be fairly typical in nebulae during early star formation.
“O-type stars have relatively short lifespan, say around 1 million years for the brightest O-star in Orion – which is 40 times the mass of our Sun – compared to the 10 billion year lifespan of less massive stars like our Sun,” Di Francesco told Universe Today. “Since these clusters are typically the only places where O-stars form, I’d say that this type of event is indeed typical in nebulae hosting early star formation.”
It’s common for new-born stars to be within close proximity of each other in such stellar nurseries as M42. Researchers in the study found that any proplyds within the extreme-UV envelope of a massive star would have its disk shredded in short order, retaining on average less than 50% the mass of Jupiter total. Beyond the 0.1 light year “kill radius,” however, the chances for these proplyds to retain mass goes up, with researchers observing anywhere from 1 to 80 Jupiter masses of material remaining.
The findings in this study are also crucial in understanding what the early lives of stars are like, and perhaps the pedigree of our own solar system, as well as how common – or rare – our own history might be in the story of the universe.
There’s evidence that our solar system may have been witness to one or more nearby supernovae early in its life, as evidenced by isotopic measurements. We were somewhat lucky to have had such nearby events to “salt” our environment with heavy elements, but not sweep us clean altogether.
“Our own Sun likely formed in a clustered environment similar to that of Orion, so it’s a good thing we didn’t form too close to the O-stars in its parent nebula,” Di Francesco told Universe Today. “When the Sun was very young, it was close enough to a high-mass star so that when it blew up (went supernova) the proto-solar system was seeded with certain isotopes like Al-26 that are only produced in supernova events.”
This is the eventual fate of massive O-type stars in the Orion Nebula, though none of them are old enough yet to explode in this fashion. Indeed, it’s amazing to think that peering into the Orion Nebula, we’re witnessing a drama similar to what gave birth to our Sun and solar system, billions of years ago.
The Orion Nebula is the closest active star forming region to us at about 1,500 light years distant and is just visible to the naked eye as a fuzzy patch in the pommel of the “sword” of Orion the Hunter. Looking at the Orion Nebula at low power through a small telescope, you can just make out a group of four stars known collectively as the Trapezium. These are just such massive hot and luminous O-Type stars, clearing out their local neighborhoods and lighting up the interior of the nebula like a Chinese lantern.
And thus science fact imitates fiction in an ironic twist, as it turns out that “Death Stars” do indeed blast planets – or at least protoplanetary disks – on occasion!
Be sure to check out a great piece on ALMA on a recent episode of CBS 60 Minutes:
Read the abstract and the full (paywalled) paper on ALMA Observations of the Orion Proplyds in The Astrophysical Journal.
