Planetary Formation Archives

August 31, 2014December 23, 2015 by Bob King

Tonight’s Moon-Mars-Saturn Trio Recalls Time of Terror

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 — 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.

April 30, 2014December 23, 2015 by Elizabeth Howell

Spin! Exoplanet’s Day Finishes Blazing Fast Compared To Earth

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. — 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.

Source: European Southern Observatory

March 26, 2014December 23, 2015 by Elizabeth Howell

Surprise! Asteroid Hosts A Two-Ring Circus Above Its Surface

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) — 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.

Source: European Southern Observatory

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) — 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)

March 13, 2014April 26, 2016 by David Dickinson

“Death Stars” Caught Blasting Proto-Planets

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 recent press 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.”

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.

March 7, 2014December 23, 2015 by Elizabeth Howell

Giant Planet May Be Lurking In ‘Poisonous’ Gas Around Beta Pictoris

Artist's conception of a hypothetical giant planet (left) in Beta Pictoris. The gas giant would sweep up comets into a swarm, causing frequent collisions. Astronomers using the Atacama Large Millimeter Array (ALMA) are calling this the "preferred model" for observations they made. Credit: Goddard Space Flight Center/F. Reddy

A Saturn-mass planet might be lurking in the debris surrounding Beta Pictoris, new measurements of a debris field around the star shown. If this could be proven, this would be the second planet found around that star.

The planet would be sheparding a giant swarm of comets (some in front and some trailing behind the planet) that are smacking into each other as often as every five minutes, new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) show. This is the leading explanation for a cloud of carbon monoxide gas visible in the array.

“Although toxic to us, carbon monoxide is one of many gases found in comets and other icy bodies,” stated Aki Roberge, an astrophysicist at NASA’s Goddard Space Flight Center in Maryland who participated in the research. “In the rough-and-tumble environment around a young star, these objects frequently collide and generate fragments that release dust, icy grains and stored gases.”

ALMA captured millimeter-sized light from carbon monoxide and dust around Beta Pictoris, which is about 63 light-years from Earth (relatively close to our planet). The gas seems to be most prevalent in an area about 8 billion miles (13 kilometers) from the star — the equivalent distance of three times the length of Neptune’s location from the sun. The carbon monoxide cloud itself makes up about one-sixth the mass of Earth’s oceans.

Ultraviolet light from the star should be breaking up the carbon monoxide molecules within 100 years, so the fact there is so much gas indicates something must be replenishing it, the researchers noted. Their models showed that the comets would need to be destroyed every five minutes for this to happen (unless we are looking at the star at an unusual time).

While the researchers say they need more study to see how the gas is concentrated, their hypothesis is there is two clumps of gas and it is due to a big planet behaving similarly to what Jupiter does in our solar system. Thousands of asteroids follow behind and fly in front of Jupiter due to the planet’s massive gravity. In this more distant system, it’s possible that a gas giant planet would be doing the same thing with comets.

If the gas turns out to be in just one clump, however, another scenario would suggest two Mars-sized planets (icy ones) smashing into each other about half a million years ago. This “would account for the comet swarm, with frequent ongoing collisions among the fragments gradually releasing carbon monoxide gas,” NASA stated.

The research was published yesterday (March 6) in the journal Science and is led by Bill Dent, a researcher at the Joint ALMA Office in Chile. You can read more information in press releases from NASA, the National Radio Astronomy Observatory and European Southern Observatory.

January 31, 2014April 26, 2016 by Elizabeth Howell

Young Planets Migrated In Double-Star Systems, Model Shows

Artist's conception of Kepler 34b, which orbits two stars. Credit: David A. Aguilar (CfA)

Binary star systems are downright dangerous due to their complex gravitational interactions that can easily grind a planet to pieces. So how is it that we have found a few planets in these Tattooine-like environments?

Research led by the University of Bristol show that most planets formed far away from their central stars and then migrated in at some point in their history, according to research collected concerning Kepler-34b and other exoplanets.

The scientists did “computer simulations of the early stages of planet formation around the binary stars using a sophisticated model that calculates the effect of gravity and physical collisions on and between one million planetary building blocks,” stated the university.

“They found that the majority of these planets must have formed much further away from the central binary stars and then migrated to their current location.”

You can read more about the research in Astrophysical Journal Letters. It was led by Bristol graduate student Stefan Lines with participation from advanced research fellow and computational astrophysicst Zoe Lienhardt, among other collaborators.

January 21, 2014December 23, 2015 by Shannon Hall

Surprise! Fomalhaut’s Kid Sister Has a Debris Disk Too

The bright star Fomalhaut hosts a spectacular debris disk: a dusty circling plane of small objects where planets form. At a mere 25 light-years away, we’ve been able to pinpoint detailed features: from the warm disk close by to the further disk that is comparable to the Solar System’s Kuiper belt.

But Fomalhaut never ceases to surprise us. At first we discovered a planet, Fomalhaut b, which orbits in the clearing between the two disks. Then we discovered that Fomalhaut was not a single star or a double star, but a triplet. The breaking news today, however, is that we have discovered a mini debris disk around the third star.

Fomalhaut is massive, weighing in at 1.9 times the mass of the Sun. And at such a close distance it’s one of the brightest stars in the southern sky. But its two companions are much smaller. The second star, Fomalhaut B, is 0.7 times the mass of the Sun and the third star, Fomalhaut C, a small red dwarf, is 0.2 times the mass of the Sun.

Fomalhaut C orbits Fomalhaut A at a distance of 2.5 light-years, or roughly half the distance from the Sun to the closest neighboring star. It was only confirmed to be gravitationally bound to Fomalhaut A and Fomalhaut B in October of last year.

“The disk around Fomalhaut C was a complete surprise,” lead researcher Grant Kennedy of the University of Cambridge told Universe Today. “This is only the second system in which disks around two separate stars have been discovered.”

Relatively cool dust and ice particles are much brighter at long wavelengths, allowing telescopes like the Herschel Space Telescope, to pick up the excess infrared light. However, Herschel has a much poorer resolution than an optical telescope so the image of Fomalhaut C’s disk is not spatially resolved — meaning the brightness of the disk could be measured but not its structure.

Kennedy’s team’s best guess is that the disk is quite cold, around 24 degrees Kelvin and pretty small, orbiting to and extent of 10 times the distance from the Earth to the Sun. But it’s likely that it’s similar to Fomalhaut A’s disk in that it’s bright, elliptical, and slightly offset from its host star. All three characteristics suggest that gravitational perturbations may be destabilizing the cometary orbits within the disks.

“As a stellar system Fomalhaut’s gotten very interesting in the last year,” Kennedy said. With two wide companions “it’s not obvious how the configuration came about. Forming one wide companion is not so hard, but getting a second is very unlikely. So we need to come up with a new mechanism.”

Kennedy is currently working on figuring out what exactly this “new mechanism” is and he thinks the debris disk around Fomalhaut C will provide a few helpful hints. His best guess is still under construction but it’s likely that a small star is disturbing the system.

The next step will be to watch the stellar system over the next few years in order to measure their orbits exactly. With precise motions we just might be able to see what is interrupting the system.

“We think these observations will provide a good test of the theory,” Kennedy told Universe Today. They just might “solve the mystery of why the Fomalhaut system looks like it does.”

The paper has been published in the Monthly Notices of the Royal Astronomical Society and is available for download here.

January 16, 2014December 23, 2015 by Matthew Francis

Some Planet-like Kuiper Belt Objects Don’t Play “Nice”

Distribution of Kuiper belt objects (green), along with various other outer Solar System bodies, based on data from the Minor Planet Center. [Credit: Minor Planet Center; Murray and Dermott]

The Kuiper belt — the region beyond the orbit of Neptune inhabited by a number of small bodies of rock and ice — hides many clues about the early days of the Solar System. According to the standard picture of Solar System formation, many planetesimals were born in the chaotic region where the giant planets now reside. Some were thrown out beyond the orbit of Neptune, while others stayed put in the form of Trojan asteroids (which orbit in the same trajectory as Jupiter and other planets). This is called the Nice model.

However, not all Kuiper belt objects (KBOs) play nicely with the Nice model.

(I should point out that the model is named named for the city in France and therefore pronounced “neese”.) A new study of large scale surveys of KBOs revealed that those with nearly circular orbits lying roughly in the same plane as the orbits of the major planets don’t fit the Nice model, while those with irregular orbits do. It’s a puzzling anomaly, one with no immediate resolution, but it hints that we need to refine our Solar System formation models.

This new study is described in a recently released paper by Wesley Fraser, Mike Brown, Alessandro Morbidelli, Alex Parker, and Konstantin Baygin (to be published in the Astrophysical Journal, available online). These researchers combined data from seven different surveys of KBOs to determine roughly how many of each size of object are in the Solar System, which in turn is a good gauge of the environment in which they formed.

The difference between this and previous studies is the use of absolute magnitudes — a measure of how bright an object really is — as opposed to their apparent magnitudes, which are simply how bright an object appears. The two types of magnitude are related by the distance an object is from Earth, so the observational challenge comes down to accurate distance measurements. Absolute magnitude is also related to the size of an KBO and its albedo (how much light it reflects), both important physical quantities for understanding formation and composition.

Finding the absolute magnitudes for KBOs is more challenging than apparent magnitudes for obvious reasons: these are small objects, often not resolved as anything other than points of light in a telescope. That means requires measuring the distance to each KBO as accurately as possible. As the authors of the study point out, even small errors in distance measurements can have a large effect on the estimated absolute magnitude.

The bodies in the Kuiper Belt. Credit: Don Dixon

In terms of orbits, KBOs fall into two categories: “hot” and “cold”, confusing terms having nothing to do with temperature. The “cold” KBOs are those with nearly circular orbits (low eccentricity, in mathematical terms) and low inclinations, meaning their trajectories lie nearly in the ecliptic plane, where the eight canonical planets also orbit. In other words, these objects have nearly planet-like orbits. The “hot” KBOs have elongated orbits and higher inclinations, behavior more akin to comets.

The authors of the new study found that the hot KBOs have the same distribution of sizes as the Trojan asteroids, meaning there are the same relative number of small, medium, and large KBOs and similarly sized Trojans. That hints at a probable common origin in the early days of the Solar System. This is in line with the Nice model, which predicts that, as they migrated into their current orbits, the giant planets kicked many planetesimals out beyond Neptune.

However, the cold KBOs don’t match that pattern at all: there are fewer large KBOs relative to smaller objects. To make matters more strange, both hot and cold seem to follow the same pattern for the smaller bodies, only deviating at larger masses, which is at odds with expectations if the cold KBOs formed where they orbit today.

To put it another way, the Nice model as it stands could explain the hot KBOs and Trojans, but not the cold. That doesn’t mean all is lost, of course. The Nice model seems to do very well except for a few nagging problems, so it’s unlikely that it’s completely wrong. As we’ve learned from studying exoplanet systems, planet formation models are a work in progress — and astronomers are an ingenious lot.

December 6, 2013December 23, 2015 by Elizabeth Howell

This Exoplanet Is Turning Planetary Formation Scenarios Upside Down

Artist's conception of a planet like HD106906 b. Visible in the picture is a debris disk and its distant host star. Credit: NASA/JPL-Caltech

What the heck is that giant exoplanet doing so far away from its star? Astronomers are still trying to figure out the curious case of HD 106906 b, a newly found gas giant that orbits at an astounding 650 astronomical units or Earth-sun distances from its host star. For comparison, that’s more than 20 times farther from its star than Neptune is from the sun.

“This system is especially fascinating because no model of either planet or star formation fully explains what we see,” stated Vanessa Bailey, a graduate astronomy student at the University of Arizona who led the research.

HD 106906 b is 11 times the size of Jupiter, throwing conventional planetary formation theory for a loop. Astronomers believe that planets gradually form from clumps of gas and dust that circle around young stars, but that process would take too long for this exoplanet to form — the system is just 13 million years old. (Our own planetary system is about 4.5 billion years old, by comparison.)

The discovery image of HD 106906 b, shown in thermal infrared light from instruments on the Magellan telescope at the European Southern Observatory in Chile. The image has been changed to take out light from its very bright host star. The planet orbits more than 20 times farther from its host star than Neptune does from the sun. (AU = astronomical units, or Earth-sun distances). Credit: Vanessa Bailey

Another theory is that if the disc collapses quickly, perhaps it could spawn a huge planet — but it’s improbable that there is enough mass in the system for that to happen. Perhaps, the team says, this system is like a “mini binary star system”, with HD 106906 b being more or less a failed star of some sort. Yet there is at least one problem with that theory as well; the mass ratio of the planet and star is something like 1 to 100, and usually these scenarios occur in ratios of 1 to 10 or less.

“A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit,” Bailey stated.

“It is possible that in the case of the HD 106906 system the star and planet collapsed independently from clumps of gas, but for some reason the planet’s progenitor clump was starved for material and never grew large enough to ignite and become a star.”

Young binarys stars: Image credit: NASA — Young binary stars: Image credit: NASA

Besides puzzling out how HD 106906 b came to be, astronomers are also interested in the system because they can clearly see leftovers or a debris disk from the system’s formation. By studying this system further, astronomers hope to figure out more about how young planets evolve.

At 2,700 degrees Fahrenheit (1,500 degrees Celsius), the planet is most easily visible in infrared. The heat is from when the planet was first coalescing, astronomers said.

The astronomers spotted the planet using the Magellan telescope at the European Southern Observatory’s Atacama Desert in Chile. It was visible in both the Magellan Adaptive Optics (MagAO) system and Clio2 thermal infrared camera on the telescope. The planet was confirmed using Hubble Space Telescope images from eight years ago, as well as the FIRE spectrograph on Magellan that revealed more about the planet’s “nature and composition”, a press release stated.

The research paper is now available on the prepublishing site Arxiv and will be published in a future issue of Astrophysical Journal Letters.

Source: University of Arizona

October 10, 2013December 23, 2015 by Elizabeth Howell

Baby Free-Floating Planet Found Alone, Away From A Star

Artist's conception of PSO J318.5-22. Credit: MPIA/V. Ch. Quetz

The planetary world keeps getting stranger. Scientists have found free-floating planets — drifting alone, away from stars — before. But the “newborn” PSO J318.5-22 (only 12 million years old) shows properties similar to other young planets around young stars, even though there is no star nearby the planet.

“We have never before seen an object free-floating in space that that looks like this. It has all the characteristics of young planets found around other stars, but it is drifting out there all alone,” stated team leader Michael Liu, who is with the Institute for Astronomy at the University of Hawaii at Manoa. “I had often wondered if such solitary objects exist, and now we know they do.”

Image from the Pan-STARRS1 telescope of the free-floating planet PSO J318.5-22, in the constellation of Capricornus. Credit: N. Metcalfe & Pan-STARRS 1 Science Consortium

The planet is about 80 light-years from Earth, which is quite close, and is part of a star group named after Beta Pictoris that also came together about 12 million years ago. There is a planet in orbit around Beta Pictoris itself, but PSO J318.5-22 has a lower mass and likely had a different formation scenario, the researchers said.

Astronomers uncovered the planet, which is six times the mass of Jupiter, while looking for brown dwarfs or “failed stars.” PSO J318.5-22’s ultra-red color stood apart from the other objects in the survey, astronomers said.

The free-floating planet was identified in the Pan-STARRS 1 wide-field survey telescope in Maui. Follow-up observations were performed with several other Hawaii-based telescopes, including the NASA Infrared Telescope Facility, the Gemini North Telescope, and the Canada-France-Hawaii Telescope.

The discovery will soon be detailed in Astrophysical Letters, but for now you can read the prepublished verison on Arxiv.

Source: Institute for Astronomy at the University of Hawaii