Posted on by Tammy Plotner

Crystal Rain Cradles Infant Star

NASA's Spitzer Space Telescope detected tiny green crystals, called olivine, thought to be raining down on a developing star. Image credit: NASA/JPL-Caltech/University of Toledo

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Thanks to the infrared eye of the Spitzer Space Telescope, researchers have captured evidence of “crystal rain” collapsing around a forming star. These tiny bits of green mineral – olivine – are also found in meteorites, but it’s the first time it has been observed in the dusty embryo of the stellar creation process. While it’s still unclear how these crystals formed, the suspect may be jets of superheated gas.

“If you could somehow transport yourself inside this protostar’s collapsing gas cloud, it would be very dark,” said Charles Poteet, lead author of the new study, also from the University of Toledo. “But the tiny crystals might catch whatever light is present, resulting in a green sparkle against a black, dusty backdrop.”

Located in the constellation of Orion, protostar HOPS-68 shares its forsterite crystals with a host of terrestrial souces, too. The forsterite crystal rain chemical compositions belongs to the olivine family of silicate minerals. Not only is it found in meteorites, but it’s part of common Earthly deposits, such as a periodot gemstone and the green sand beaches of Hawaii. In space you’ll find it in remote galaxies and NASA’s Stardust and Deep Impact missions both located the crystals in their close-up studies of comets. But it takes a mighty furnace to forge forsterite.

“You need temperatures as hot as lava to make these crystals,” said Tom Megeath of the University of Toledo in Ohio. He is the principal investigator of the research and the second author of a new study appearing in Astrophysical Journal Letters. “We propose that the crystals were cooked up near the surface of the forming star, then carried up into the surrounding cloud where temperatures are much colder, and ultimately fell down again like glitter.”

While the presence of olivine might be new, capturing the forsterite signature has occurred before – spotted in the swirling, planet-forming disks that surround young stars. What’s unusual is finding it in such at cool temperature… about minus 280 degrees Fahrenheit (minus 170 degrees Celsius). This leads researchers to believe the crystals are cooked below then “served up” in the outer structure. This line of reasoning might also explain why comets also contain the same minerals. As the rocky travellers move through infant solar systems, they collect the crystals where they have moved away to cooler climes.

Could this be true of what we know of our own solar system’s formation? Poteet and his colleagues say it’s plausible, but speculate that jets might have lifted crystals into the collapsing cloud of gas surrounding our early sun before raining onto the outer regions of our forming solar system. Eventually, the crystals would have been frozen into comets. The Herschel Space Observatory, a European Space Agency-led mission with important NASA contributions, also participated in the study by characterizing the forming star.

“Infrared telescopes such as Spitzer and now Herschel are providing an exciting picture of how all the ingredients of the cosmic stew that makes planetary systems are blended together,” said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington.

Original story source can be found at JPL News.

Posted on by Anne Minard

‘Armada of Telescopes’ Captures Most Distant Galaxy Cluster Ever Seen

Hubble infrared image showing CL J1449+0856, the most distant mature cluster of galaxies found. Color data was added from ESO’s Very Large Telescope and the NAOJ’s Subaru Telescope. Credit: NASA, ESA, R. Gobat (Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS–)

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The galaxies above are among the oldest objects astronomers have ever laid eyes — er, telescopes — on, formed when the Universe was less than a quarter of its current age. In a new study out in the journal Astronomy & Astrophysics, a team of researchers has announced that they’ve used a fleet of the world’s most powerful telescopes to measure the distance from here to there.

And things look awfully familiar.

“The surprising thing is that when we look closely at this galaxy cluster it doesn’t look young — many of the galaxies have settled down and don’t resemble the usual star-forming galaxies seen in the early Universe,” said lead author Raphael Gobat of Université Paris Diderot in France.

The Very Large Telescope (VLT) at ESO's Cerro Paranal observing site in the Atacama Desert of Chile, consisting of four Unit Telescopes with main mirrors 8.2-m in diameter and four movable 1.8-m diameter Auxiliary Telescopes. The telescopes can work together, in groups of two or three, to form a giant interferometer, allowing astronomers to see details up to 25 times finer than with the individual telescopes. Credit: Iztok Boncina/ESO

Clusters of galaxies are the largest structures in the Universe that are held together by gravity. Astronomers expect these clusters to grow over time so that massive clusters would be rare in the early Universe. Although even more distant clusters have been seen, they appear to be young clusters in the process of formation, not settled mature systems.

The international team of astronomers used the powerful VIMOS and FORS2 instruments on ESO’s Very Large Telescope (VLT) to measure the distances to some of the blobs in a curious patch of very faint red objects first observed with the Spitzer space telescope. This grouping, named CL J1449+0856  for its position in the sky, had all the hallmarks of being a very remote cluster of galaxies. The results showed that we are indeed seeing a galaxy cluster as it was when the Universe was about three billion years old.

Once the team knew the distance to this very rare object, they looked carefully at the component galaxies using both Hubble and ground-based telescopes, including the VLT. They found evidence suggesting that most of the galaxies in the cluster were not forming stars, but were composed of stars that were already about one billion years old. This makes the cluster a mature object, similar in mass to the Virgo Cluster, the nearest rich galaxy cluster to the Milky Way.

Further evidence that this is a mature cluster comes from observations of X-rays coming from CL J1449+0856 made with ESA’s XMM-Newton space observatory. The cluster is giving off X-rays that must be coming from a very hot cloud of tenuous gas filling the space between the galaxies and concentrated towards the center of the cluster. This is another sign of a mature galaxy cluster, held firmly together by its own gravity, as very young clusters have not had time to trap hot gas in this way.

As Gobat concludes, “These new results support the idea that mature clusters existed when the Universe was less than one quarter of its current age. Such clusters are expected to be very rare according to current theory, and we have been very lucky to spot one. But if further observations find many more then this may mean that our understanding of the early Universe needs to be revised.”

Source: ESO press release. The research appears in a paper, “A mature cluster with X-ray emission at z = 2.07,” by R. Gobat et al., published in the journal Astronomy & Astrophysics. (see also arxiv). Lead author’s affiliation page: Université Paris Diderot.

Posted on by Nancy Atkinson

Spitzer Captures a Pink Sunflower in Space

Classifying Galaxies
This image from NASA's Spitzer Space Telescope shows infrared light from the Sunflower galaxy, otherwise known as Messier 63. Spitzer's view highlights the galaxy's dusty spiral arms. Image credit: NASA/JPL-Caltech

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Looking out my own window this morning provides a gloomy overcast view, so this new image from the Spitzer Space Telescope provides a day-brightener: a pink sunflower! This is the Sunflower galaxy, also known as Messier 63, and with Spitzers’ infrared eyes, the arms of the galaxy show up vividly. Infrared light is sensitive to the dust lanes in spiral galaxies, which appear dark in visible-light images. Spitzer’s view reveals complex structures that trace the galaxy’s spiral arm pattern.

Source: JPL
This galaxy is about 37 million-light years away from Earth, and lies close to the well-known Whirlpool galaxy and the associated Messier 51 group of galaxies.

Posted on by Nancy Atkinson

Spitzer’s Stunning New View of the North American Nebula

This swirling landscape of stars is known as the North American nebula. In visible light, the region resembles North America, but in this new infrared view from NASA's Spitzer Space Telescope, the continent disappears. Image credit: NASA/JPL-Caltech

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In visible light, the North American nebula resembles its namesake continent. But looking at it in the infrared spectrum, a whole new perspective explodes into view. Clouds of dust and gas come to life, as light from massive young star heats and shape the clouds, and dramatic clusters of baby stars which can only be seen in infrared burst into view.

“One of the things that makes me so excited about this image is how different it is from the visible image, and how much more we can see in the infrared than in the visible,” said Luisa Rebull of NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. Rebull is lead author of a paper about the observations, accepted for publication in the Astrophysical Journal Supplement Series. “The Spitzer image reveals a wealth of detail about the dust and the young stars here.”

Rebull and her team have identified more than 2,000 new, candidate young stars in the region. There were only about 200 known before. Because young stars grow up surrounded by blankets of dust, they are hidden in visible-light images. Spitzer’s infrared detectors pick up the glow of the dusty, buried stars.

This new view of the North American nebula combines both visible and infrared light observations, taken by the Digitized Sky Survey and NASA's Spitzer Space Telescope, respectively, into a single vivid picture. Image credit: NASA/JPL-Caltech

Combing infrared data with light from other parts of the spectrum gives astronomers a complete picture of star formation. Each different combination of observations gives insights into star formation.

But in Spitzer’s infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

In this image, astronomers can see stars at all stages of life, from the early years when it is swaddled in dust to early adulthood, when it has become a young parent to a family of developing planets. Sprightly “toddler” stars with jets can also be identified in Spitzer’s view.

“This is a really busy area to image, with stars everywhere, from the North American complex itself, as well as in front of and behind the region,” said Rebull. “We refer to the stars that are not associated with the region as contamination. With Spitzer, we can easily sort this contamination out and clearly distinguish between the young stars in the complex and the older ones that are unrelated.”

There are a couple of mysteries about the North American Nebula still to be solved: astronomers think there must be more stars in the “Gulf of Mexico” region that must dominate the nebula and provide the main source of “power.” There is a dark tangle of clouds there that even Spitzers powerful infrared eyes can’t penetrate, but some light appears to be coming from behind that region, in the same way that sunlight creeps out from behind a rain cloud.

The nebula’s distance from Earth is also a mystery. Current estimates put it at about 1,800 light-years from Earth. Spitzer will refine this number by finding more stellar members of the North American complex.

See more info on the JPL website, where you can download full resolution versions of the images seen here, and more views of the North American nebula.

Posted on by Jon Voisey

M33’s “Object-X”

Often times, objects that are unremarkable in one portion of the spectra, can often be vivid in others. In M33, the Triangulum Galaxy, a star that’s barely visible in the optical, stands out as the second brightest source (and single brightest single star) in the mid-infrared. This unusual star has been the target of a recent study, led by Rubab Khan at the Ohio State University and may help astronomers to understand an unusual supernova from 2008.

The supernova 2008S occurred February first in NGC 6946, the Fireworks Galaxy. Since it happened in a galaxy that is relatively nearby, astronomers seized the opportunity to explore the progenitor star in archival images. Yet images from the Large Binocular Telescope and other optical observatories could not find a star that could be identified as a parent. Instead, the detection of the star responsible came from Spitzer, an infrared observatory. Observations from this instrument indicated that the star responsible may have been unexpectedly low mass for such a powerful explosion leading other astronomers to question whether or not SN 2008S was a true supernova, or merely an impostor in the form of an eruption of a Luminous Blue Variable (LBV), which tend to be more massive stars and would be in stark contradiction to the Spitzer findings.

Yet, regardless of the nature of the nature of SN 2008S, teams all seemed to agree that the progenitor had only been detected in the infrared because it was veiled by a thick curtain of dust. So to help better understand this class of dusty stars, astronomers have been working to uncover more of them, against which they can test their hypotheses.

To find these objects, astronomers have been searching the infrared portion of the spectrum for objects that are exceptionally bright yet lack optical counterparts. The brightest of the stellar sources in M33 features faint star in the red portion of the optical spectrum from the Local Group Galaxies Survey published in 2007, but no star at all in archival records with similar limiting magnitudes from 1949 and 1991. The authors of the new study have dubbed this odd source, Object-X.

The team rules out the possibility that the object could be a young stellar object (YSO), blocked by a thick dust disc along the line of sight, noting that models of even the thickest dust discs still predict more light to be scattered back along the line of sight. Instead, the team concludes that Object-X must be a self-obscured star that has undergone relatively recent mass loss which has cooled to form either graphite or silicate dust. Depending on which type of dust is predominant, the team was able to fit the data to two wildly different temperatures for the star: either 5000 K for graphite, or 20,000 K for the silicate. In all cases, the predicted mass for the central star was always greater than 30 solar masses.

In general, there are two mechanisms by which a star can eject material to form such a curtain. The first is through stellar winds, which increase as the star enters the red giant phase, swelling up and lowering the force of gravity near the surface. The second is “impulsive mass ejections” in which stars shudder and throw mass off that way. A classical example of this is Eta Carinae. The team predicts from the features they found, that Object-X is most likely a cool hypergiant. The fact that the star was completely obscured until very recently hints that the mass loss is not constant (as stellar wind), but patchy, coming from frequent eruptions. As the shell of dust expands, the star should reemerge in the optical, becoming visible again in the next few decades.

Posted on by Nicholos Wethington

The Zooniverse is Expanding: The Milky Way Project Begins Today

The Milky Way Project allows anyone to help catalog bubbles and other interesting features in images taken from a robotic infrared survey. Image Credit: Spitzer/The Milky Way Project

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From the folks that brought you the addictive citizen science projects Galaxy Zoo and Moon Zoo (among others), comes yet another way to explore our Universe and help out scientists at the same time. The Milky Way Project invites members of the public to look at images from infrared surveys of our Milky Way and flag features such as gas bubbles, knots of gas and dust and star clusters.

As with the other Zooniverse projects, the participation of the public is a core feature. Accompanying the Milky Way Project is a way for Zooniverse members – lovingly called “zooites” – to discuss the images they’ve cataloged. Called Milky Way Talk, users can submit images they find curious or just plain beautiful to the talk forum for discussion.

The Milky Way Project uses data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) and the Multiband Imaging Photometer for Spitzer Galactic Plane Survey (MIPSGAL). These two surveys have imaged the Milky Way in infrared light at different frequencies. GLIMPSE at 3.6, 4.5, 5.8, and 8 microns, and MIPSGAL at 24 and 70 microns. In the infrared, things that don’t emit much visible light – such as large gas clouds excited by stellar radiation – are apparent in images.

The new project aims at cataloging bubbles, star clusters, knots of gas and dark nebulae. All of these objects are interesting in their own ways.

Bubbles – large structures of gas in the galactic plane – belie areas where young stars are altering the interstellar medium that surrounds them. They heat up the dust and/or ionize the gas that surrounds them, and the flow of particles from the star pushes the diffuse material surrounding out into bubble shapes.

The green knots are where the gas and dust are more dense, and might be regions that contain stellar nurseries. Similarly, dark nebulae – nebulae that appear darker than the surrounding gas – are of interest to astronomers because they may also point to stellar formation of high-mass stars.

Star clusters and galaxies outside of the Milky Way may also be visible in some of the images. Though the cataloging of these objects isn’t the main focus of the project, zooites can flag them in the images for later discussion. Just like in the other Zooniverse projects, which use data from robotic surveys, there is always the chance that you will be the first person ever to look at something in one of the images. You could even be like Galaxy Zoo member Hanny and discover something that astronomers will spend telescope time looking at!

This image is full of objects that are interesting to astronomers for study. You can help them pick out which things to study. Image Credit: Spitzer/The Milky Way Project

The GLIMPSE-MIPSGAL surveys were performed by the Spitzer Space Telescope. Over 440,000 images – all taken in the infrared – are in the catalog and need to be sifted through. This is a serious undertaking, one that cannot be accomplished by graduate students in astronomy alone.

In cataloging these bubbles for subsequent analysis, Milky Way Project members can help astronomers understand both the interstellar medium and the stars themselves imaged by the survey. It will also help them to make a map of the Milky Way’s stellar formation regions.

As with the other Zooniverse projects, this newest addition relies on the human brain’s ability to pick out patterns. Diffuse or oddly-shaped bubbles – such as those that appear “popped” or are elliptical – are difficult for a computer to analyze. So, it’s up to willing members of the public to help out the astronomy community. The Zooniverse community boasts over 350,000 members participating in their various projects.

A little cataloging and research of these gas bubbles has already been done by researchers. The Milky Way Project site references work by Churchwell, et. al, who cataloged over 600 of the bubbles and discovered that 75% of the bubbles they looked at were created by type B4-B9 stars, while 0-B3 stars make up the remainder (for more on what these stellar types mean, click here).

A zoomable map that uses images from the surveys – and has labeled a lot of the bubbles that have been already cataloged by the researchers- is available at Alien Earths.

For an extensive treatment of just how important these bubbles are to understanding stars and their formation, the paper “IR Dust Bubbles: Probing the Detailed Structure and Young Massive Stellar Populations of Galactic HII Regions” by Watson, et. al is available here.

If you want to get cracking on drawing bubbles and cataloging interesting features of our Milky Way, take the tutorial and sign up today.

Sources: The Milky Way Project, Arxiv, GLIMPSE

Posted on by Nancy Atkinson

Astronomy Cast Ep. 208: The Spitzer Space Telescope

The Spitzer Space Telescope. Credit: NASA

Last week we talked about Lyman Spitzer, and this week we’ll take a look at the orbiting observatory that bears his name: the Spitzer Space Telescope. Designed to see into the infrared spectrum, Spitzer has returned images of objects that were previously hidden to astronomers by thick shrouds of gas and dust.

Click here to download the episode

Spitzer Space Telescope – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Nancy Atkinson

Astronomy Cast Ep. 207: Lyman Spitzer

Lyman Spitzer

Time for another action-packed double episode of Astronomy Cast. This week we focus on the Lyman Spitzer, a theoretical physicist and astronomer who worked on star formation and plasma physics. Of course, this will lead us into next week’s episode where we talk about the mission that bears his name: the Spitzer Space Telescope.

Click here to download the episode

Lyman Spitzer – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Nancy Atkinson

Buckyballs Could Be Plentiful in the Universe

An infrared photo of the Small Magellanic Cloud taken by Spitzer is shown here in this artist's illustration, with two callouts. The middle callout shows a magnified view of an example of a planetary nebula, and the right callout shows an even further magnified depiction of buckyballs, which consist of 60 carbon atoms arranged like soccer balls. Image credit: NASA/JPL-Caltech

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Earlier this year, astronomers using the Spitzer Space Telescope announced they had found – for the first time — carbon molecules, known as “buckyballs,” in space. They were detected in one planetary nebula, and even though they were predicted to be rather prevalent out in space, no one was really sure. Until now. They’ve now been found in the space between stars, and around four more planetary nebulae, with one dying star in a nearby galaxy holding a staggering quantity of buckyballs — the equivalent mass of 15 times that of Earth’s Moon.

“It turns out that buckyballs are much more common and abundant in the universe than initially thought,” said astronomer Letizia Stanghellini of the National Optical Astronomy Observatory in Tucson, Ariz. “Spitzer had recently found them in one specific location, but now we see them in other environments. This has implications for the chemistry of life. It’s possible that buckyballs from outer space provided seeds for life on Earth.”

Buckyballs are soccer-ball-shaped molecules that were first observed in a laboratory 25 years ago, and are named for their resemblance to architect Buckminster Fuller’s geodesic domes, which have interlocking circles on the surface of a partial sphere. Also known as C60, and Fullerenes, they are the third major form of pure carbon; graphite and diamond are the other two. They have been thought to be common in space since they have been found in meteorites, and also in more everyday materials such as soot.

While two different studies announced today confirm that buckyballs could be widespread in space, they are turning up in places where astronomers thought they couldn’t exist. So, obviously we don’t have these molecules fully figured out yet.

All the planetary nebulae in which buckyballs have been detected are rich in hydrogen. This goes against what researchers thought for decades — they had assumed that, as is the case with making buckyballs in the lab, hydrogen could not be present. The hydrogen, they theorized, would contaminate the carbon, causing it to form chains and other structures rather than the spheres, which contain no hydrogen at all.

“We now know that fullerenes and hydrogen coexist in planetary nebulae, which is really important for telling us how they form in space,” said Anibal García-Hernández from the Instituto de Astrofísica de Canarias, Spain, lead author, working with Stanghellini on a paper appearing online Oct. 28 in the Astrophysical Journal Letters.

Using Spitzer, this team found the buckyballs around three dying sun-like stars, called planetary nebulae, in the our own Milky Way galaxy, plus in another planetary nebula the Small Magellanic Cloud, a nearby galaxy. This was particularly exciting to the researchers, because, in contrast to the planetary nebulae in the Milky Way, the distance to this galaxy is known. Knowing the distance to the source of the buckyballs meant that the astronomers could calculate their quantity — two percent of Earth’s mass, or the equivalent mass of 15 times that of Earth’s Moon.

Planetary nebulae are made of material shed from the dying stars.

Another Spitzer study about the discovery of buckyballs in space was also recently published in the Astrophysical Journal Letters, (October 10, 2010) and was led by Kris Sellgren of Ohio State University, Columbus. This study found that buckyballs are also present in the space between stars, but not too far away from young solar systems.

They were found among two nebulae; NGC 2023, located near the well-known Horsehead Nebula in the constellation of Orion, and the second, NGC 7023, known as the Iris Nebula, in the constellation Cepheus.
These are the largest molecules ever discovered floating between the stars. Astronomers aren’t sure yet if these cosmic balls formed in a nearby planetary nebula and wandered away, or if they perhaps can spring up in interstellar space.

“It’s exciting to find buckyballs in between stars that are still forming their solar systems, just a comet’s throw away,” Sellgren said. “This could be the link between fullerenes in space and fullerenes in meteorites.”
Since carbon is the key building block for life as we know it, their perhaps prevalent existence in space is intriguing.

“Now that there are buckyballs confirmed in the interstellar medium and in circumstellar space, it’s likely that chemists will get more interested in the astrobiological implications of these fascinating molecules,” Sellgren said.

Sources: JPL, NOAO,, CalTech/Spitzer

, Earlier detection of Buckyballs in Space — NASA

Posted on by Nicholos Wethington

The Strange Warm Spot of upsilon Andromedae b

The warmest part of upsilon Andromedae b is not directly under the light coming from its host star, as would be expected. Image Credit: NASA/JPL-Caltech

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If you set a big black rock outside in the Sun for a few hours, then go and touch it, you’d expect the warmest part of the rock to be that which was facing the Sun, right? Well, when it comes to exoplanets, your expectations will be defied. A new analysis of a well-studied exoplanetary system reveals that one of the planets – which is not a big black rock, but a Jupiter-like ball of gas – has its warmest part opposite that of its star.

The system of Upsilon Andromedae, which lies 44 light years away from the Earth in the constellation Andromeda, is a much studied system of planets that orbit around a star a little more massive and slightly hotter than our Sun.

The closest planet to the star, upsilon Andromeda b, was the first exoplanet to have its temperature taken by The Spitzer Space Telescope. As we reported back in 2006, upsilon Andromeda b was thought to be tidally locked to the star and show corresponding temperature changes at it went around its host star. That is, as it went behind the star from our perspective, the face was warmer than when it was in front of the star from our perspective. Simple enough, right? These original results were published in a paper in Science on October 27th, 2006, available here.

As it turns out, this temperature change scenario is not the case. UCLA Professor of Physics and Astronomy Brad Hansen, who is a co-author on both the 2006 paper and updated results, explains, “The original report was based on just a few hours of data, taken early in the mission, to see whether such a measurement was even possible (it is close to the limit of the expected performance of the instrument). Since the observations suggested it was possible to detect, we were awarded a larger amount of time to do it in more detail.”

Observations of upsilon Andromedae b were taken with the Spitzer again in February of 2009. Once the astronomers were able to study the planet more, they discovered something odd – just how warm the planet was when it passed in front of the star from our perspective was a lot warmer than when it passed behind, just the opposite of what one would expect, and opposite of the results they originally published. Here’s a link to an animation that helps explain this strange feature of the planet.

What the astronomers discovered – and have yet to explain fully – is that there is a “warm spot” about 80 degrees opposite of the face of the planet that is pointed towards the star. In other words, the warmest spot on the planet is not on the side of the planet that is receiving the most radiation from the star.

This in itself is not a novelty. Hansen said, “There are several exoplanets observed with warm spots, including some whose spots are shifted relative to the location facing the star (an example is the very well studied system HD189733b). The principal difference in this case is that the shift we observe is the largest known.”

Upsilon Andromedae b does not transit in front of its star from our vantage point on the Earth. Its orbit is inclined by about 30 degrees, so it appears to be passing “below” the star as it comes around the front. This means that astronomers cannot use the transit method of exoplanetary study to get a handle on its orbit, but rather measure the tug that the planet exerts on the star. It has been determined that upsilon Andromedae b orbits about every 4.6 days, has a mass 0.69 that of Jupiter and is about 1.3 Jupiter radii in diameter. To get a better idea of the whole system of upsilon Andromedae, see this story we ran earlier this year.

So what, exactly, could be causing this bizarrely placed warm spot on the planet? The paper authors suggest that equatorial winds – much like those on Jupiter – could be transferring heat around the planet.

A graph and visual representation of the hot spot as the planet orbits the star upsilon Andromedae. Image credit: NASA/JPL-Caltech/UCLA

Hansen explained, “At the sub-stellar point (the one closest to the star) the amount of radiation being absorbed from the star is highest, so the gas there is heated more. It will therefore have a tendency to flow away from the hot region towards cold regions. This, combined with rotation will give a “trade wind”-like structure to the gas flow on the planet… The big uncertainty is how that energy is eventually dissipated. The fact that we observe a hot spot at roughly 90 degrees suggests that this occurs somewhere near the “terminator” (the day/night edge). Somehow the winds are flowing around from the sub-stellar point and then dissipating as they approach the night side. We speculate that this may be from the formation of some kind of shock front.”

Hansen said that they are unsure just how large this warm spot is. “We have only a very crude measure of this, so we have modeled as basically two hemispheres – one hotter than the other. One could make the spot smaller and make it correspondingly hotter and you would get the same effect. So, one can trade off spot size versus temperature contrast while still matching the observations.”

The most recent paper, which is co-authored by members from the United States and the UK, will appear in the Astrophysical Journal. If you’d like to go outside and see the star upsilon Andromedae,here’s a star chart.

Source: JPL Press Release, Arxiv here and here , email interview with Professor Brad Hansen.