Posted on by Nancy Atkinson

Sunny Side Up: New Image of the Fried Egg Nebula Reveals a Rare Yellow Hypergiant Star

An image from the Very Large Telescope of IRAS 17163-3907, which has a huge dusty double shell surrounding the central hypergiant star. The star and its shells resemble an egg white around a yolky centre, leading astronomers to nickname the object the Fried Egg Nebula. Credit: ESO/E. Lagadec

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A new look at the Fried Egg Nebula has revealed one of the rarest classes of stars in the Universe, a yellow hypergiant. This “sunny-side-up” view shows for the first time a huge dusty double shell surrounding this huge star.

“This object was known to glow brightly in the infrared but, surprisingly, nobody had identified it as a yellow hypergiant before,” said Eric Lagadec from the European Southern Observatory, who led the team that produced the new images.

And there’s good reason to keep an eye on this star: it will likely soon die an explosive death, and will be one of the next supernova explosions in our galaxy.

The monster star, IRAS 17163-3907 has a diameter about a thousand times bigger than our Sun. At a distance of about 13,000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500,000 times more brightly than the Sun. The total mass of this star is estimated to be roughly twenty times that of the Sun.

The star and its shells resemble an egg white around a yolky center, hence, the nickname of the Fried Egg Nebula – which is much easier to say than IRAS 17163-3907.

The observations of the star and the discovery of its surrounding shells were made using the VISIR infrared camera on the VLT. The pictures are the first of this object to clearly show the material around it and reveal two almost perfectly spherical shells.

Astronomers say that if the Fried Egg Nebula were placed in the center of the Solar System, Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface. The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10,000 times the distance from the Earth to the Sun.

Yellow hypergiants are in an extremely active phase of their evolution, undergoing a series of explosive events — this star has ejected four times the mass of the Sun in just a few hundred years. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and mixed with gas.

Source: ESO

Posted on by Tammy Plotner

Stellar Superburst: Neutron Star Blows Away Model

A detailed rendering of the neutron star surface and what the surface might look like during the explosion. Credit: NASA/Dana Berry

[/caption]Imagine an event so catastrophic that it pours more energy out in three hours than the Sun does in a hundred years. Now imagine it a reality. In a study done by Yuri Cavecchi et al. (2011), they’ve witnessed a neutron star outburst which has put all computer modeling for thermodynamic explosions on extreme objects back to square one.

Apparently a strong magnetic field around accreting pulsar IGR J17480-2446 is the culprit for some areas of the star to ignite in the extreme. X-ray binary IGR J17480-2446, as a general rule, should be about one and a half times the mass of the Sun confined in an area of about 25km. This creates a strong gravitational field which extracts gas from its orbiting companion. In turn, this collects on the surface of the primary and kindles a fast, high-energy thermonuclear reaction. In a perfect scenario, this reaction would be spread over the surface evenly, but for some reason in about 10% of case studies some areas burn brighter than others. Just why this happens is a true enigma.

In order to better understand the phenomena, theoretical models were created to test out spin rates. They suggest that rapid rotation stops the burning material from spreading uniformly – much like the Coriolis force develops terrestrial hurricanes. Another hypothesis proposes these conflagrations ride on global-scale waves where one side stays cool and dim as it rises, while the other remains hot and bright. But just which one is viable in the case of this strange pulsar?

“We explore the origin of Type I burst oscillations in IGR J17480–2446 and conclude that they are not caused by global modes in the neutron star ocean. We also show that the Coriolis force is not able to confine an oscillation-producing hot-spot on the stellar surface.” says lead author Yuri Cavecchi (University of Amsterdam, the Netherlands). “The most likely scenario is that the burst oscillations are produced by a hot-spot confined by hydromagnetic stresses.”

What makes the astronomers think this way? One explanation might be the strange properties of J17480 itself. While it obeys the rules when it comes to forming bright patches during thermonuclear events, it break them when it comes to spin rates. Why does this particular star only rotate about 10 times per second when the next slowest does it at 245? This is where the magnetic field theory comes into play. Perhaps when explosions occur, it’s held in place by this invisible, yet powerful, force.

“More theoretical work is needed to confirm this, but in the case of J17480 it is a very plausible explanation for our observations”, says Cavecchi. Co-author Anna Watts further explains their new models – while interesting – might not account for all non-uniform events seen in similar situations. “The new mechanism may only work in stars like this one, with magnetic fields that are strong enough to stop the flame front from spreading. For other stars with this odd burning behavior, the old models might still apply.”

Original Information Source: Netherlands Research School for Astronomy. For Further Reading: Implications of burst oscillations from the slowly rotating accreting pulsar IGR 17480-2446 in the globular cluster Terzan 5.

Posted on by Tammy Plotner

Solo Star Synthesis

Young binary stars. Image credit: NASA

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“Swing your partner round and round… Out of the cluster and out of town” While that’s a facetious description as to how binary stars end up losing their companions, it’s not entirely untrue. In practicing the field of astronomy, we’re quite aware that not all stars are single entities and at least half of the stellar population of the Milky Way consists of binaries. However, explaining just exactly why some are loners and others belong to multiple systems has been somewhat of a mystery. Now a team of astronomers from Bonn University and the Max-Planck-Institute for Radio astronomy think they have the answer…

The team recently published their results in a paper in the journal Monthly Notices of the Royal Astronomical Society. Apparently the environment that forms a particular group of stars plays a huge role in how many stars lead a lone existence – or have one or more companions. For the most part, star-forming nebulae produce binary stars in clustered groups. These groups then quickly disband into their parent galaxy and at least half of them become loners. But why do some double stars end up leading a solitary life? The answer might very well be how they interact gravitationally.

“In many cases the pairs are torn apart into two single stars, in the same way that a pair of dancers might be separated after colliding with another couple on a crowded dance floor”, explains Michael Marks, a PhD student and member of the International Max-Planck Research School for Astronomy and Astrophysics.

If this is the case, then single stars take on that state long before they spread out into a galaxy. Since conditions in star-forming regions vary widely in both appearance and population, science is taking a closer look at density. The more dense the region is, the more binary stars form – and the greater the interaction that splits them apart. Every cluster of stars has a different population, too.. And that population is dependant on the initial density. By using computer modeling, astronomers are able to determine what regions are most likely to contribute single stars are multiple systems to their host galaxy.

“Working out the composition of the Milky Way from these numbers is simple: We just add up the single and binary stars in all the dispersed groups to build a population for the wider galaxy”, says Kroupa. Michael Marks further explains how this concept applies universally: “This is the first time we have been able to compute the stellar content of a whole galaxy, something that was simply not possible until now. With our new method we can now calculate the stellar contents of many different galaxies and work out how many single and binary stars they have.”

Original Story Source: RAS News. For further reading: Notices of the Royal Astronomical Society. Animations of the interactions of binary stars.

Posted on by Jon Voisey

Help! My Stars are Leaking!

A fast-moving star, Alpha Camelopardalis, creates a stunning bow shock in this new image from WISE. Credit: NASA/JPL-Caltech/WISE Team

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Star clusters are wonderful test beds for theories of stellar formation and evolution. One of the key roles they play is to help astronomers understand the distribution of stellar masses as stars form (in other words, how many high mass stars versus intermediate and low mass stars), known as the Initial Mass Function (IMF). One of the problems is that this is constantly evolving away from the initial distribution as stars die or are ejected from the cluster. As such, understanding these mechanisms is essential for astronomers looking to backtrack from the current population to the IMF.

To assist in this goal, astronomers led by Vasilii Gvaramadze at the University of Bonn in Germany are engaged in a study to search young clusters for stars in the process of being ejected.

In the first of two studies released by the team so far, they studied the cluster associated with the famous Eagle Nebula. This nebula is well known due to the famous “Pillars of Creation” image taken by the aging Hubble Space Telescope which shows towers of dense gas currently undergoing star formation.

Two main methods exist for discovering stars on the lam from their birthplace. The first is to examine stars individually and analyze their motion in the plane of the sky (proper motion) along with their motion towards or away from us (radial velocity) to determine if a given star has sufficient velocity to escape the cluster. While this method can be reliable, it suffers because the clusters are so far away, even though the stars could be moving at hundreds of kilometers per second, it takes long periods of time to detect it.

Instead, the astronomers in these studies search for runaway stars by the effects they have on the local environment. Since young clusters contain large amounts of gas and dust, stars plowing through it will create bow shocks, similar to those a boat makes in the ocean. Taking advantage of this, the team searched the Eagle Nebula cluster for signs of bow shocks from these stars. Searching images from several studies, the team found three such bow shocks. The same method was used in a second study, this time analyzing a lesser known cluster and nebula in Scorpius, NGC 6357. This survey turned up seven bow shocks of stars escaping the region.

In both studies, the team analyzed the spectral types of the stars which would indicate their mass. Simulations of nebulae suggested that the majority of ejected stars are given their initial kick as they have a close pass to the center of a cluster where the density is the highest. Studies of clusters have shown that their centers are often dominated by massive O and B spectral type stars which would mean that such stars would be preferentially ejected. These two studies have helped to confirm that prediction as all of the stars discovered to have bow shocks were massive stars in this range.

While this method is able to find runaway stars, the authors note that it is an incomplete survey. Some stars may have sufficient velocity to escape, but still fall under the local sound speed in the nebula which would prevent them from creating a bow shock. As such, calculations have predicted that roughly 20% of escaping stars should create detectable bow shocks.

Understanding this mechanism is important because it is expected to play the dominant role in the evolution of the mass distribution of clusters early in their life. An alternative method of ejection involves stars in a binary orbit. If one star becomes a supernova, the sudden mass loss suddenly decreases the gravitational force holding the second star in orbit, allowing it to fly away. However, this method requires that a cluster at least be old enough for stars to have evolved to the point they explode as supernova, delaying this mechanism’s importance until at least that point and allowing the gravitational sling-shot effects to dominate early on.

Posted on by Nancy Atkinson

Colorful Cluster of Stars Competes with the Tarantula Nebula

The star cluster NGC 2100 in the Large Magellanic Cloud. Credit: ESO

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Who can shine the brightest in the Large Magellanic Cloud? A brilliant cluster of stars, open cluster NGC 2100 shines brightly, competing with the nearby Tarantula Nebula for bragging rights in this image from ESO’s New Technology Telescope (NTT).

Observers perhaps often overlook NGC 2100 because of its close proximity to the impressive Tarantula. The glowing gas of the Tarantula Nebula even tries to steal the limelight in this image — the bright colors here are from the nebula’s outer regions, and is lit up by the hot young stars that lie within the nebula itself.

But back to the star cluster — this brilliant star cluster is around 15 million years old, and located in the Large Magellanic Cloud, a nearby satellite galaxy of the Milky Way. An open cluster has stars that are relatively loosely bound by gravity. These clusters have a lifespan measured in tens or hundreds of millions of years, as they eventually disperse through gravitational interaction with other bodies.

This new picture was created from exposures through several different color filters.The stars are shown in their natural colors, while light from glowing ionized hydrogen (shown here in red) and oxygen (shown in blue) is overlaid.

See more info at the ESO website.

Posted on by Nancy Atkinson

“Impossible” Star Exists in Cosmic Forbidden Zone

This ancient star, in the constellation of Leo (The Lion), is called SDSS J102915+172927 and has been found to have the lowest amount of elements heavier than helium of all stars yet studied. It has a mass smaller than that of the Sun and is probably more than 13 billion years old. Credit: ESO/Digitized Sky Survey 2

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Astronomers say a newly found star should not exist and is in the “forbidden zone” of a widely accepted theory of star formation. The star, called SDSS J102915+172927, is composed almost entirely of hydrogen and helium, with only remarkably small amounts of other chemical elements in it. And how should this star be classified? We suggest either ‘easy listening’ or ‘jazz,’ as this star is certainly not heavy metal! But it may be one of the oldest stars ever found.

This faint star is located in the constellation of Leo (The Lion), and has the lowest amount of elements heavier than helium (what astronomers call “metals”) of all stars yet studied. It has a mass smaller than that of the Sun and is probably more than 13 billion years old.

“A widely accepted theory predicts that stars like this, with low mass and extremely low quantities of metals, shouldn’t exist because the clouds of material from which they formed could never have condensed,” said Elisabetta Caffau (Zentrum für Astronomie der Universität Heidelberg, Germany and Observatoire de Paris, France), lead author of the paper appearing in this week’s edition of Nature. “It was surprising to find, for the first time, a star in this ‘forbidden zone’, and it means we may have to revisit some of the star formation models.”

The team found the star with the X-shooter and UVES instruments on the Very Large Telescope. This allowed them to measure how abundant the various chemical elements were in the star. They found that the proportion of metals in SDSS J102915+172927 is more than 20,000 times smaller than that of the Sun.

“The star is faint, and so metal-poor that we could only detect the signature of one element heavier than helium — calcium — in our first observations,” said Piercarlo Bonifacio (Observatoire de Paris, France), who supervised the project. “We had to ask for additional telescope time from ESO’s Director General to study the star’s light in even more detail, and with a long exposure time, to try to find other metals.”

This picture shows the distribution of the light of different colours coming from the remarkable star SDSS J102915+172927 after it has been split up by the X-Shooter instrument on the ESO VLT. Credit: ESO/E. Caffau

The prevailing theory is that hydrogen and helium were created shortly after the Big Bang, together with some lithium, while almost all other elements were formed later in stars. Supernova explosions spread the stellar material into the interstellar medium, making it richer in metals. New stars form from this enriched medium so they have higher amounts of metals in their composition than the older stars. Therefore, the proportion of metals in a star tells us how old it is.

“The star we have studied is extremely metal-poor, meaning it is very primitive. It could be one of the oldest stars ever found,” adds Lorenzo Monaco from ESO, also involved in the study.

Also very surprising was the lack of lithium in SDSS J102915+172927. Such an old star should have a composition similar to that of the Universe shortly after the Big Bang, with a few more metals in it. But the team found that the proportion of lithium in the star was at least fifty times less than expected in the material produced by the Big Bang.

“It is a mystery how the lithium that formed just after the beginning of the Universe was destroyed in this star.” Bonifacio added.

Is this star one-of-a-kind? Probably not, the researchers say. “We have identified several more candidate stars that might have metal levels similar to, or even lower than, those in SDSS J102915+172927. We are now planning to observe them with the VLT to see if this is the case,” said Caffau.

Read the team’s paper (pdf file)

Source: ESO

Posted on by Tammy Plotner

Hubble Movies “Star” Supersonic Jets

Astronomers have combined two decades of Hubble observations to make unprecedented movies revealing never-before-seen details of the birth pangs of new stars. This sheds new light on how stars like the Sun form. Credit: Hubble/ESA

[/caption]Don’t you know that you are a shooting star… Thanks to the NASA/ESA Hubble Space Telescope, an international team of scientists led by astronomer Patrick Hartigan of Rice University in Houston, USA, has done something pretty incredible. Using photos and information gathered from the last 14 years of observations, they’ve sewn together an unprecedented look at young jets ejected from three stars. Be prepared to be “blown” away…

The time-lapse sequence of “moving pictures” offers us an opportunity to witness activity that takes place over several years in just a few seconds. Active jets can remain volatile for periods of up to 100,000 years and these movies reveal details never seen – like knots of gas brightening and dimming – and collisions between fast-moving and slow-moving material. These insights allow scientists to form a clearer picture of stellar birth.

“For the first time we can actually observe how these jets interact with their surroundings by watching these time-lapse movies,” said Hartigan. “Those interactions tell us how young stars influence the environments out of which they form. With movies like these, we can now compare observations of jets with those produced by computer simulations and laboratory experiments to see which aspects of the interactions we understand and which we don’t understand.”

As a star forms in its collapsing cloud of cold gas, it gushes out streams of material in short bursts, pushing out from its poles at speeds of up to about 600,000 miles an hour. As the star ages, it spins material and its gravity attracts even more, creating a disc which may eventually become protoplanetary. The fast moving jets may be restricted by the neophyte star’s magnetic fields and could cease when the material runs out. However, by looking at this supposition in action, new questions arise. It would appear that the dust and gas move at different speeds.

“The bulk motion of the jet is about 300 kilometers per second,” Hartigan said. “That’s really fast, but it’s kind of like watching a stock car race; if all the cars are going the same speed, it’s fairly boring. The interesting stuff happens when things are jumbling around, blowing past one another or slamming into slower moving parts and causing shockwaves.”

But the “action” doesn’t stop there. In viewing these sequential shockwaves, the team was at a loss to understand the dynamics behind the collisions. By enlisting the aid of colleagues familiar with the physics of nuclear explosions, they quickly discovered a recognizable pattern.

“The fluid dynamicists immediately picked up on an aspect of the physics that astronomers typically overlook, and that led to a different interpretation for some of the features we were seeing,” Hartigan explained. “The scientists from each discipline bring their own unique perspectives to the project, and having that range of expertise has proved invaluable for learning about this critical phase of stellar evolution.”

Hartigan began using Hubble to collect still frames of stellar jets in 1994 and his findings are so complex he has employed the aid of experts in fluid dynamics from Los Alamos National Laboratory in New Mexico, the UK Atomic Weapons Establishment, and General Atomics in San Diego, California, as well as computer specialists from the University of Rochester in New York. The Hubble sequence movies have been such a scientific success that Hartigan’s team is now conducting laboratory experiments at the Omega Laser facility in New York to understand how supersonic jets interact with their environment.

“Our collaboration has exploited not just large laser facilities such as Omega, but also computer simulations that were developed for research into nuclear fusion,” explains Paula Rosen of the UK Atomic Weapons Establishment, a co-author of the research. “Using these experimental methods has enabled us to identify aspects of the physics that the astronomers overlooked — it is exciting to know that what we do in the laboratory here on Earth can shed light on complex phenomena in stellar jets over a thousand light-years away. In future, even larger lasers, like the National Ignition Facility at the Lawrence Livermore National Laboratory in California, will be able explore the nuclear processes that take place within stars.”

And all the world will love you just as long… as long as you are… a shooting star!

Original Story Source and Video Presentation: Hubble News. For further reading, Rice University News.

Posted on by Jason Major

Shiny New Supernova Spotted in Nearby Galaxy

Supernova PTF11kly in M101 on August 24, 2011. Credit: BJ Fulton, LCOGT.

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Literally an event of stellar proportions, a new Type Ia supernova has been identified in a spiral galaxy 25 million light-years away! Spotted by Caltech’s Palomar Transit Factory project, this supernova, categorized as PTF11kly, is located 58″.6 west and 270″.7 south of the center of M101. It was first seen yesterday, August 24, 2011.

According to AAVSO Special Notice #250 P. Nugent et al. reported in Astronomical Telegram #3581 that a possible Type-Ia supernova has been discovered by the Palomar Transient Factory shortly after eruption in the galaxy M101 and has been designated “PTF11kly”. The object is currently at a magnitude of 17.2, but may well rise by several magnitudes. The object is well placed within M101 for good photometry, and observations of this potential bright SNIa are strongly encouraged.

There are currently no comparison stars available in VSP for this field; please indicate clearly the comparison stars that you use for photometry when reporting observations to AAVSO. Please retain your images and/or photometry for recalibration when comparison star magnitudes are available.

Need coordinates? The (J2000) coordinates reported for the object are RA: 14:03:05.81 , Dec: +54:16:25.4. Messier 101 is located in the constellation of Ursa Major at RA: 14h 03m 12.6s Dec: +54 20′ 57″

Charts for PTF11kly may be plotted with AAVSO VSP. You should select the DSS option when plotting, as the galaxy will not appear on standard charts. This object has been assigned the name “PTF11kly” for use with AAVSO VSP and WebObs; please use this name when reporting observations until it is conclusively classified as a supernova and a proper SN name is assigned.

Image of M101 and PTF11kly by Joseph Brimacombe.

Type Ia supernovae are the result of a binary pair of mismatched stars, the smaller, denser one feeding on material drawn off its larger companion until it can no longer take in any more material. It then explodes in a catastrophic event that outshines the brightness of its entire galaxy! Astronomers believe that Type Ia supernovae occur in pretty much the same fashion every time and thus, being visible across vast distances, have become invaluable benchmarks for measuring distance in the Universe and gauging its rate of expansion.

The fact that this supernova was spotted literally within a day of its occurrence – visibly speaking, of course, since M101 is 25 million light-years away and thus 25 million years in our past – will be extremely handy for astronomers who will have the opportunity to study the event from beginning to end and learn more about some of the less-understood processes involved in Type Ia events.

“We caught this supernova earlier than we’ve ever discovered a supernova of this type. On Tuesday, it wasn’t there. Then, on Wednesday, boom! There it was – caught within hours of the explosion. As soon as I saw the discovery image I knew we were onto something big.”

– Andy Howell, staff scientist at Las Cumbres Observatory Global Telescope

It’s a big Universe and there are a lot of stars and therefore a lot of supernovae, but getting a chance to study one occurring so recently in a galaxy so relatively close to our own is something that is getting many astronomers very excited.

So, get those CCD camera out and best of luck!

Keep up with the latest news on PTF11kly on the rochesterastronomy.org site, and check out Phil Plait’s informative article on his BadAstronomy blog. Also read the press release from the University of California here.

Tammy Plotner also contributed to this article.

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Jason Major is a graphic designer, photo enthusiast and space blogger. Visit his website Lights in the Dark and follow him on Twitter @JPMajor and on Facebook for more astronomy news and images!

Posted on by Tammy Plotner

WISE Discovers Some Really “Cool” Stars!

This artist's conception illustrates what a "Y dwarf" might look like. Y dwarfs are the coldest star-like bodies known. Image credit: NASA/JPL-Caltech

[/caption]What would you say if I told you there are stars with a temperature close to that of a human body? Before you have me committed, there really is such a thing. These “cool” stars belong to the brown dwarf family and are termed Y dwarfs. For over ten years astronomers have been hunting for these dark little beasties with no success. Now infrared data from NASA’s Wide-field Infrared Survey Explorer (WISE) has turned up six of them – and they’re less than 40 light years away!

“WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision,” said Jon Morse, Astrophysics Division director at NASA Headquarters in Washington. “They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground.”

Often referred to as “failed stars”, the Y-class suns are simply too low mass to ignite the fusion process which makes other stars shine in visible light. As they age, they fade away – their only signature is what can be spotted in infrared. The brown dwarfs are of great interest to astronomers because we can gain a better understanding as to stellar natures and how planetary atmospheres form and evolve. Because they are alone in space, it’s much easier to study these Jupiter-like suns… without being blinded by a parent star.

“Brown dwarfs are like planets in some ways, but they are in isolation,” said astronomer Daniel Stern, co-author of the Spitzer paper at JPL. “This makes them exciting for astronomers — they are the perfect laboratories to study bodies with planetary masses.”

The WISE mission has been extremely productive – turning up more than 100 brown dwarf candidates. Scientists are hopeful that even more will emerge as huge amounts of data are processed from the most advanced survey of the sky at infrared wavelengths to date. Just imagine how much information was gathered from January 2010 to February 2011 as the telescope scanned the entire sky about 1.5 times! One of the Y dwarfs, called WISE 1828+2650, is the record holder for the coldest brown dwarf, with an estimated atmospheric temperature cooler than room temperature, or less than about 80 degrees Fahrenheit (25 degrees Celsius).

“The brown dwarfs we were turning up before this discovery were more like the temperature of your oven,” said Davy Kirkpatrick, a WISE science team member at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, Calif. “With the discovery of Y dwarfs, we’ve moved out of the kitchen and into the cooler parts of the house.”

Kirkpatrick is the lead author of a paper appearing in the Astrophysical Journal Supplement Series, describing the 100 confirmed brown dwarfs. Michael Cushing, a WISE team member at NASA’s Jet Propulsion Laboratory in Pasadena, California, is lead author of a paper describing the Y dwarfs in the Astrophysical Journal.

“Finding brown dwarfs near our Sun is like discovering there’s a hidden house on your block that you didn’t know about,” Cushing said. “It’s thrilling to me to know we’ve got neighbors out there yet to be discovered. With WISE, we may even find a brown dwarf closer to us than our closest known star.”

Given the nature of the Y-class stars, positively identifying these special brown dwarfs wasn’t an easy task. For that, the WISE team employed the aid of the Spitzer Space Telescope to refine the hunt. From there the team used the most powerful telescopes on Earth – NASA Infrared Telescope Facility atop Mauna Kea, Hawaii; Caltech’s Palomar Observatory near San Diego; the W.M. Keck Observatory atop Mauna Kea, Hawaii; and the Magellan Telescopes at Las Campanas Observatory, Chile, and others – to look for signs of methane, water and even ammonia. For the very coldest of the new Y dwarfs, the team used NASA’s Hubble Space Telescope. Their final answer came when changes in spectra indicated a low temperature atmosphere – and a Y-class signature.

“WISE is looking everywhere, so the coolest brown dwarfs are going to pop up all around us,” said Peter Eisenhardt, the WISE project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California, and lead author of a recent paper in the Astronomical Journal on the Spitzer discoveries. “We might even find a cool brown dwarf that is closer to us than Proxima Centauri, the closest known star.”

How cool is that?!

Original Story Source: JPL News Release.

Posted on by Tammy Plotner

Graphenes In Spaaaaaace!

Artist’s impression of the graphenes (C24) and fullerenes found in a Planetary Nebula. The detection of graphenes and fullerenes around old stars as common as our Sun suggests that these molecules and other allotropic forms of carbon may be widespread in space. Credits: IAC; original image of the Helix Nebula (NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner, STScI, & T.A. Rector, NRAO.)

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And just where have your buckyballs been lately? More technically known as fullerenes, this magnetic form of carbon shows some pretty interesting properties deduced from laboratory work here on Earth. But even more interesting is its cousin – graphene. And guess where it’s been found?!

When you picture a fullerene, you conjure up a mental image of carbon atoms arranged in a three-dimensional configuration with two structures: C60 which patterns out similar to a soccer ball and C70 which more closely resembles a rugby ball. Both of these types of “buckyballs” have been detected in space, but the real kicker is graphene. Its technical name is planar C24 and instead of being geodesic, it’s the thinnest substance known. Just one atom thick, this flat sheet of carbon is a portrait in extraordinary strength, conductivity and elasticity. Graphene was first synthesized in the lab in 2004 and now planar C24 may have been detected in space.

Through the use of the Spitzer Space Telescope, a team of astronomers led by Domingo Aníbal García-Hernández of the Instituto de Astrofísica de Canarias in Spain have not only picked up a C70 fullerene molecule, but may have also detected graphene as well. “If confirmed with laboratory spectroscopy – something that is almost impossible with the present techniques – this would be the first detection of graphene in space” said García-Hernández.

Letizia Stanghellini and Richard Shaw, members of the team at the National Optical Astronomy Observatory in Tucson, Arizona suspect collisional shocks generated in stellar winds of planetary nebulae could be responsible for the presence of fullerenes and graphenes through the destruction of hydrogenated amorphous carbon grains (HACs). “What is particularly surprising is that the existence of these molecules does not depend on the stellar temperature, but on the strength of the wind shocks” says Stanghellini.

So where has this discovery taken place? Try the Magellanic Clouds. In this case, using a planetary nebula “closer to home” is not part of the equation because science needs to be certain the material they are looking at is indeed the by-product of a planetary nebula and not a mix. Fortunately the SMG is known to be metal-poor, which enhances the chances of spotting complex carbon molecules. Right now the challenge has been to pinpoint the evidence for graphene from Spitzer data.

“The Spitzer Space Telescope has been amazingly important for studying complex organic molecules in stellar environments” says Stanghellini. “We are now at the stage of not only detecting fullerenes and other molecules, but starting to understand how they form and evolve in stars.” Shaw adds “We are planning ground-based follow up through the NOAO system of telescopes. We hope to find other molecules in planetary nebulae where fullerene has been detected to test some physical processes that might help us understand the biochemistry of life.”

Original News Source: National Optical Astronomy Observatory News Release.