Very Large Telescope Archives

July 23, 2018 by Matt Williams

This is a Photo of Neptune, From the Ground! ESO’s New Adaptive Optics Makes Ground Telescopes Ignore the Earth’s Atmosphere

This image of the planet Neptune was obtained during the testing of the Narrow-Field adaptive optics mode of the MUSE/GALACSI instrument on ESO’s Very Large Telescope. The corrected image is sharper than a comparable image from the NASA/ESA Hubble Space Telescope. Credit: ESO/P. Weilbacher (AIP)

In 2007, the European Southern Observatory (ESO) completed work on the Very Large Telescope (VLT) at the Paranal Observatory in northern Chile. This ground-based telescope is the world’s most advanced optical instrument, consisting of four Unit Telescopes with main mirrors (measuring 8.2 meters in diameter) and four movable 1.8-meter diameter Auxiliary Telescopes.

Recently, the VLT was upgraded with a new instrument known as the Multi Unit Spectroscopic Explorer (MUSE), a panoramic integral-field spectrograph that works at visible wavelengths. Thanks to the new adaptive optics mode that this allows for (known as laser tomography) the VLT was able to recently acquire some images of Neptune, star clusters and other astronomical objects with impeccable clarity.

In astronomy, adaptive optics refers to a technique where instruments are able to compensate for the blurring effect caused by Earth’s atmosphere, which is a serious issue when it comes to ground-based telescopes. Basically, as light passes through our atmosphere, it becomes distorted and causes distant objects to become blurred (which is why stars appear to twinkle when seen with the naked eye).

*Images of the planet Neptune obtained during the testing of the Narrow-Field adaptive optics mode of the MUSE/GALACSI instrument on ESO’s Very Large Telescope. Credit: ESO/P. Weilbacher (AIP*

One solution to this problem is to deploy telescopes into space, where atmospheric disturbance is not an issue. Another is to rely on advanced technology that can artificially correct for the distortions, thus resulting in much clearer images. One such technology is the MUSE instrument, which works with an adaptive optics unit called a GALACSI – a subsystem of the Adaptive Optics Facility (AOF).

The instrument allows for two adaptive optics modes – the Wide Field Mode and the Narrow Field Mode. Whereas the former corrects for the effects of atmospheric turbulence up to one km above the telescope over a comparatively wide field of view, the Narrow Field mode uses laser tomography to correct for almost all of the atmospheric turbulence above the telescope to create much sharper images, but over a smaller region of the sky.

This consists of four lasers that are fixed to the fourth Unit Telescope (UT4) beaming intense orange light into the sky, simulating sodium atoms high in the atmosphere and creating artificial “Laser Guide Stars”. Light from these artificial stars is then used to determine the turbulence in the atmosphere and calculate corrections, which are then sent to the deformable secondary mirror of the UT4 to correct for the distorted light.

Using this Narrow Field Mode, the VLT was able to capture remarkably sharp test images of the planet Neptune, distant star clusters (such as the globular star cluster NGC 6388), and other objects. In so doing, the VLT demonstrated that its UT4 mirror is able to reach the theoretical limit of image sharpness and is no longer limited by the effects of atmospheric distortion.

*The most powerful laser guide star system in the world sees first light at the Paranal Observatory. Credit: ESO*

This essentially means that it is now possible for the VLT to capture images from the ground that are sharper than those taken by the Hubble Space Telescope. The results from UT4 will also help engineers to make similar adaptations to the ESO’s Extremely Large Telescope (ELT), which will also rely on laser tomography to conduct its surveys and accomplish its scientific goals.

These goals include the study of supermassive black holes (SMBHs) at the centers of distant galaxies, jets from young stars, globular clusters, supernovae, the planets and moons of the Solar System, and extra-solar planets. In short, the use of adaptive optics – as tested and confirmed by the VLT’s MUSE – will allow astronomers to use ground-based telescopes to study the properties of astronomical objects in much greater detail than ever before.

In addition, other adaptive optics systems will benefit from work with the Adaptive Optics Facility (AOF) in the coming years. These include the ESO’s GRAAL, a ground layer adaptive optics module that is already being used by the Hawk-I infrared wide-field imager. In a few years, the powerful Enhanced Resolution Imager and Spectrograph (ERIS) instrument will also be added to the VLT.

Between these upgrades and the deployment of next-generation space telescopes in the coming years (like the James Webb Space Telescope, which will be deploying in 2021), astronomers expect to bringing a great deal more of the Universe “into focus”. And what they see is sure to help resolve some long-standing mysteries, and will probably create a whole lot more!

And be sure to enjoy these videos of the images obtained by the VLT of Neptune and NGC 6388, courtesy of the ESO:

Further Reading: ESO

July 4, 2018 by Matt Williams

Stunning First Ever Photograph of a Newly Forming Planet

This spectacular image from the SPHERE instrument on ESO's Very Large Telescope is the first clear image of a planet caught in the very act of formation around the dwarf star PDS 70. Credit: ESO/A. Müller et al.

For decades, the most widely-accepted view of how our Solar System formed has been the Nebular Hypothesis. According to this theory, the Sun, the planets, and all other objects in the Solar System formed from nebulous material billions of years ago. This dust experienced a gravitational collapse at the center, forming our Sun, while the rest of the material formed a circumstellar debris ring that coalesced to form the planets.

Thanks to the development of modern telescopes, astronomers have been able to probe other star systems to test this hypothesis. Unfortunately, in most cases, astronomers have only been able to observe debris rings around stars with hints of planets in formation. It was only recently that a team of European astronomers were able to capture an image of a newborn planet, thus demonstrating that debris rings are indeed the birthplace of planets.

The team’s research appeared in two papers that were recently published in Astronomy & Astrophysics, titled “Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70” and “Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk.” The team behind both studies included member from the Max Planck Institute for Astronomy (MPIA) as well as multiple observatories and universities.

*Near infrared image of the PDS70 disk obtained with the SPHERE instrument. Credit: ESO/A. Müller, MPIA*

For the sake of their studies, the teams selected PDS 70b, a planet that was discovered at a distance of 22 Astronomical Units (AUs) from its host star and which was believed to be a newly-formed body. In the first study – which was led by Miriam Keppler of the Max Planck Institute for Astronomy – the team indicated how they studied the protoplanetary disk around the star PDS 70.

PDS 70 is a low-mass T Tauri star located in the constellation Centaurus, approximately 370 light-years from Earth. This study was performed using archival images in the near-infrared band taken by the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) instrument on the ESO’s Very Large Telescope (VLT) and the Near-Infrared Coronagraphic Imager on the Gemini South Telescope.

Using these instruments, the team made the first robust detection of a young planet (PDS 70b) orbiting within a gap in its star’s protoplanetary disc and located roughly three billion km (1.86 billion mi) from its central star – roughly the same distance between Uranus and the Sun. In the second study, led by Andre Muller (also from the MPIA) the team describes how they used the SPHERE instrument to measure the brightness of the planet at different wavelengths.

From this, they were able to determine that PDS 70b is a gas giant that has about nine Jupiter masses and a surface temperature of about 1000 °C (1832 °F), making it a particularly “Hot Super-Jupiter”. The planet must be younger than its host star, and is probably still growing. The data also indicated that the planet is surrounded by clouds that alter the radiation emitted by the planetary core and its atmosphere.

Thanks to the advanced instruments used, the team was also able to acquire an image of the planet and its system. As you can see from the image (posted at top) and the video below, the planet is visible as a bright point to the right of the blackened center of the image. This dark region is due to a corongraph, which blocks the light from the star so the team could detect the much-fainter companion.

As Miriam Keppler, a postdoctoral student at the MPIA, explained in a recent ESO press statement:

“These discs around young stars are the birthplaces of planets, but so far only a handful of observations have detected hints of baby planets in them. The problem is that until now, most of these planet candidates could just have been features in the disc.”

In addition to spotting the young planet, the research teams also noted that it has sculpted the protoplanetary disc orbiting the star. Essentially, the planet’s orbit has traced a giant hole in the center of the disc after accumulating material from it. This means that PDS 70 b is still located in the vicinity of its birth place, is likely to still be accumulating material and will continue to grow and change.

For decades, astronomers have been aware of these gaps in the protoplanetary disc and speculated that they were produced by a planet. Now, they finally have the evidence to support this theory. As André Müller explained:

“Keppler’s results give us a new window onto the complex and poorly-understood early stages of planetary evolution. We needed to observe a planet in a young star’s disc to really understand the processes behind planet formation.“

These studies will be a boon to astronomers, especially when it comes to theoretical models of planet formation and evolution. By determining the planet’s atmospheric and physical properties, the astronomers have been able to test key aspects of the Nebular Hypothesis. The discovery of this young, dust-shrouded planet would not have been were if not for the capabilities of ESO’s SPHERE instrument.

This instrument studies exoplanets and discs around nearby stars using a technique known as high-contrast imaging, but also relies on advanced strategies and data processing techniques. In addition to blocking the light from a star with a coronagraph, SPHERE is able to filter out the signals of faint planetary companions around bright young stars at multiple wavelengths and epochs.

As Prof. Thomas Henning – the director at MPIA, the German co-investigator of the SPHERE instrument, and a senior author on the two studies – stated in a recent MPIA press release:

“After ten years of developing new powerful astronomical instruments such as SPHERE, this discovery shows us that we are finally able to find and study planets at the time of their formation. That is the fulfillment of a long-cherished dream.”

Future observations of this system will also allow astronomers to test other aspects of planet formation models and to learn about the early history of planetary systems. This data will also go a long way towards determining how our own Solar System formed and evolved during its early history.

Further Reading: ESO, MPIA, Astronomy & Astrophysics, Astronomy & Astrophysics (2)

March 13, 2017April 4, 2017 by Matt Williams

Strange Loner Planet Gets Astronomers’ Attention

Artist’s impression of the free-floating object known as CFBDSIR J~214947.2-040308.9. Credit: ESO/L. Calçada/P. Delorme/R. Saito/VVV Consortium.

In the hunt for exoplanets, some rather strange discoveries have been made. Beyond our Solar System, astronomers have spotted gas giants and terrestrial planets that appear to be many orders of magnitude larger than what we are used to (aka. “Super-Jupiters” and “Super-Earths”). And in some cases, it has not been entirely clear what our instruments have been detecting.

For instance, in some cases, astronomers have not been sure if an exoplanet candidate was a super-Jupiter or a brown dwarf. Not only do these substellar-mass stars fall into the same temperature range as massive gas giants, they also share many of the same physical properties. Such was the conundrum addressed by an international team of scientists who recently conduced a study of the object known as CFBDSIR 2149-0403.

Located between 117 and 143 light-years from Earth, this mysterious object is what is known as a “free-floating planetary mass object”. It was originally discovered in 2012 by a team of French and Canadian astronomers led by Dr. Phillipe Delorme of the University Grenoble Alpes using the Canada-France Brown Dwarfs Survey – a near infrared sky survey with the Canada-France Hawaii Telescope at Mauna Kea.

*The Canada France Hawaii Telescope, near the summit of Mauna Kea, Hawaii. Credit: cfht.hawaii.edu/*

The existence of this object was then confirmed using data by the Wide-field Infrared Survey Explorer (WISE), and was believed at the time to be part of a group of stars known as the AB Doradus Moving Group (30 stars that are moving through space). The data collected on this object placed its mass at between 4 and 7 Jupiter masses, its age at 20 to 200 million years, and its surface temperature at about 650-750 K.

This was the first time that such an object had constraints placed upon its mass and age using spectral data. However, questions remained about its true nature – whether it was a low mass, high-metallicity brown dwarf or a isolated planetary mass. For the sake of their study, Delorme and the international team conducted a multi-wavelength, multi-instrument observational characterization of CFBDSIR 2149-0403.

This consisted of x-ray data from the X-Shooter instrument on the ESO’s Very Large Telescope (VLT), near-infrared data from the VLT’s Hawk-1 instrument, and infrared data from the Spitzer Space Telescope and the CFHT’s Wide-field InfraRed Camera (WIRCam). As Delorme told Tomasz Nowakowski of Phys.org:

“The X-Shooter data enabled a detailed study of the physical properties of this object. However, all the data presented in the paper is really necessary for the study, especially the follow-up to obtain the parallax of the object, as well as the Spitzer photometry. Together, they enable us to get the bolometric flux of the object, and hence constraints that are almost independent from atmosphere model assumptions.”

*An artist’s conception of a T-type brown dwarf star. Credit: Wikimedia Commons/Tyrogthekreeper*

From the combined data, they were able to characterize the absolute flux of the CFBDSIR 2149-0403, obtain readings on its spectrum, and even determine the radial velocity of the object. They were therefore able to determine that it not likely a member of a moving population of stars, as was previously expected.

“We now reject our initial hypothesis that CFBDSIR 2149-0403 would be a member of the AB Doradus moving group,” said Delorme. “This removes the most robust age constraint we had. Though determining that certainly improved our knowledge of the object it also made it more difficult to study, by adding age as a free parameter.”

As for what it is, they narrowed that down to one of two possibilities. Basically, it could be a planetary-mass object with a mass of between 2 and 13 Jupiters that is less than 500 million years in age, or a high metallicity brown dwarf that is between 2 and 40 Jupiter masses and two to three billion years in age. Ultimately, they acknowledge that this uncertainty is due to the fact that our theoretical understanding of cool, low-gravity, and metallicity-enhanced bodies is not robust enough yet.

Much of this has to do with the fact that brown dwarfs and super gas giants have common physical parameters that produce very similar effects in the spectra of their atmospheres. But as astronomers gain more of an understanding of planetary formation, which is made possible by the discovery of so many extra-solar planetary systems, we might just find where the line between the smallest of stars and the largest of gas giants is drawn.

Further Reading: arXiv, Phys.org

February 9, 2015December 23, 2015 by Vanessa Janek

Two Stars On A Death Spiral Set To Detonate As A Supernova

This artist’s impression shows the central part of the planetary nebula Henize 2-428. The core of this unique object consists of two white dwarf stars, each with a mass a little less than that of the Sun. They are expected to slowly draw closer to each other and merge in around 700 million years. This event will create a dazzling supernova of Type Ia and destroy both stars. Credit: ESO/L. Calçada

Two white dwarfs circle around one other, locked in a fatal tango. With an intimate orbit and a hefty combined mass, the pair is ultimately destined to collide, merge, and erupt in a titanic explosion: a Type Ia supernova.

Or so goes the theory behind the infamous “standard candles” of cosmology.

Now, in a paper published in today’s issue of Nature, a team of astronomers have announced observational support for such an arrangement – two massive white dwarf stars that appear to be on track for a very explosive demise.

The astronomers were originally studying variations in planetary nebulae, the glowing clouds of gas that red giant stars throw off as they fizzle into white dwarfs. One of their targets was the planetary nebula Henize 2-428, an oddly lopsided specimen that, the team believed, owed its shape to the existence of two central stars, rather than one. After observing the nebula with the ESO’s Very Large Telescope, the astronomers concluded that they were correct – Henize 2-428 did, in fact, have a binary star system at its heart.

This image of the unusual planetary nebula was obtained using ESO’s Very Large Telescope at the Paranal Observatory in Chile. In the heart of this colourful nebula lies a unique object consisting of two white dwarf stars, each with a mass a little less than that of the Sun. These stars are expected to slowly draw closer to each other and merge in around 700 million years. This event will create a dazzling supernova of Type Ia and destroy both stars. Credit: ESO

“Further observations made with telescopes in the Canary Islands allowed us to determine the orbit of the two stars and deduce both the masses of the two stars and their separation,” said Romano Corradi, a member of the team.

And that is where things get juicy.

In fact, the two stars are whipping around each other once every 4.2 hours, implying a narrow separation that is shrinking with each orbit. Moreover, the system has a combined heft of 1.76 solar masses – larger, by any count, than the restrictive Chandrasekhar limit, the maximum ~1.4 solar masses that a white dwarf can withstand before it detonates. Based on the team’s calculations, Henize 2-428 is likely to be the site of a type Ia supernova within the next 700 million years.

“Until now, the formation of supernovae Type Ia by the merging of two white dwarfs was purely theoretical,” explained David Jones, another of the paper’s coauthors. “The pair of stars in Henize 2-428 is the real thing!”

Check out this simulation, courtesy of the ESO, for a closer look at the fate of the dynamic duo:

Astronomers should be able to use the stars of Henize 2-428 to test and refine their models of type Ia supernovae – essential tools that, as lead author Miguel Santander-García emphasized, “are widely used to measure astronomical distances and were key to the discovery that the expansion of the Universe is accelerating due to dark energy.” This system may also enhance scientists’ understanding of the precursors of other irregular planetary nebulae and supernova remnants.

The team’s work was published in the February 9 issue of Nature. A copy of the paper is available here.

September 26, 2014December 23, 2015 by Shannon Hall

Have Astronomers Seen a Forming Planet in Action?

Image at 7 mm wavelength of the dusty disk around the star HD 169142 obtained with the Very Large Array (VLA) at 7 mm wavelength. The positions of the protoplanet candidates are marked with plus signs (+) (Osorio et al. 2014, ApJ, 791, L36). The insert in the upper right corner shows, at the same scale, the bright infrared source in the inner disk cavity, as observed with the Very Large Telescope (VLT) at 3.8 micron wavelength (Reggiani et al. 2014, ApJ, 792, L23).

Huge disks of dust and gas encircle many young stars. Some contain circular gaps — likely the result of forming planets carving out cavities along their orbital paths — that make the disks look more like ripples in a pond than flat pancakes.

But astronomers know only a few examples, including the archetypal disk surrounding Beta Pictoris, of this transitional stage between the original disk and the young planetary system. And they have never spotted a forming planet.

Two independent research teams think they’ve observed precisely this around the star HD 169142, a young star with a disk that extends up to 250 astronomical units (AU), roughly six times greater than the average distance from the Sun to Pluto.

Mayra Osorio from the Institute of Astrophysics of Andalusia in Spain and colleagues first explored HD 169142’s disk with the Very Large Array (VLA) in New Mexico. The 27 radio dishes configured in a Y-shape allowed the team to detect centimeter-sized dust grains. Then combining their results with infrared data, which traces the presence of microscopic dust, the group was able to see two gaps in the disk.

One gap is located between 0.7 and 20 AU, and the second larger gap is located between 30 and 70 AU. In our Solar System the first would begin at the orbit of Venus and end at the orbit of Uranus, while the second would begin at the orbit of Neptune, pass Pluto’s orbit, and extend beyond.

“This structure already suggested that the disk was being modified by two planets or sub-stellar objects, but, additionally, the radio data reveal the existence of a clump of material within the external gap, located approximately at the distance of Neptune’s orbit, which points to the existence of a forming planet,” said Mayra Osorio in a news release.

Maddalena Reggiani from the Institute for Astronomy in Zurich and colleagues then tried to search for infrared sources in the gaps using the Very Large Telescope. They found a bright signal in the inner gap, which likely corresponds to a forming planet or a young brown dwarf, an object that isn’t massive enough to kick start nuclear fusion.

The team was unable to confirm an object in the second gap, likely due to technical limitations. Any object with a mass less than 18 times Jupiter’s mass will remain hidden in the data.

Future observations will shed more light on the exotic system, hopefully allowing astronomers to better understand how planets first form around young stars.

Both papers have been published in the Astrophysical Journal Letters.

September 8, 2014December 23, 2015 by Elizabeth Howell

Rosetta’s Cloudy Comet Shroud Spotted From The Ground, While Spacecraft Picks Up Dust Grains

A composite image of Rosetta's target (Comet 67P/Churyumov–Gerasimenko) obtained by the Very Large Telescope. Credit: C. Snodgrass/ESO/ESA

This picture shows it is possible to look at Rosetta’s comet from Earth, but what a lot of work it requires! The picture you see above is a composite of 40 separate images taken by the Very Large Telescope (removing the background stars).

Despite the fact that Rosetta is right next to Comet 67P/Churyumov–Gerasimenko, ground-based observatories are still useful because they provide the “big picture” on what the comet looks like and how it is behaving. It’s an observational challenge, however, as the comet is still more than 500 million kilometers (310 million miles) from the Sun and hard to see.

On top of that, the European Space Agency says the comet is sitting in a spot in the sky where it is difficult to see it generally, as the Milky Way’s prominent starry band is just behind. But what can be seen is spectacular.

“Although faint, the comet is clearly active, revealing a dusty coma extending at least 19 000 km [11,800 miles] from the nucleus,” ESA stated. “The comet’s dusty veil is not symmetrical as the dust is swept away from the Sun – located beyond the lower-right corner of the image – to begin forming a tail.”

And that dust is beginning to show up in Rosetta’s grain collector, as you can see below!

Rosetta's dust collector, Cometary Secondary Ion Mass Analyser (COSIMA), collected its first grains from Comet 67P/Churyumov–Gerasimenko in August 2014. This image shows before and after images of the collection. Credit: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/ BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S — Rosetta’s dust collector, Cometary Secondary Ion Mass Analyser (COSIMA), collected its first grains from Comet 67P/Churyumov–Gerasimenko in August 2014. This image shows before and after images of the collection. Credit: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/
BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S

Rosetta’s Cometary Secondary Ion Mass Analyser (COSIMA) picked up several dust grains in August, which you can see in the image, and are now looking at the target plate more closely to figure out more about the dust grains.

“Some will be selected for further analysis: the target plate will be moved to place each chosen grain under an ion gun which will then ablate the grain layer by layer. The material is then analyzed in a secondary ion mass spectrometer to determine its composition,” ESA stated.

All of these results were presented today (Sept. 8) at the European Planetary Science Congress 2014.

September 2, 2014December 30, 2015 by Elizabeth Howell

Amazing Video Timelapse Of Big Telescopes At Work In Chile

What’s it like to spend a night at a huge telescope observatory? Jordi Busque recorded a brilliant timelapse of the Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA). What makes this video unique is not only the exotic location in Chile, but the use of sound in the area rather than music.

Continue reading “Amazing Video Timelapse Of Big Telescopes At Work In Chile”

July 11, 2014December 23, 2015 by Shannon Hall

New VLT Observations Clear Up Dusty Mystery

The dwarf galaxy UGC 5189A, site of the supernova SN 2010jl. Image Credit: ESO

The Universe is overflowing with cosmic dust. Planets form in swirling clouds of dust around a young star; Dust lanes hide more-distant stars in the Milky Way above us; And molecular hydrogen forms on the dust grains in interstellar space.

Even the soot from a candle is very similar to cosmic carbon dust. Both consist of silicate and amorphous carbon grains, although the size grains in the soot are 10 or more times bigger than typical grain sizes in space.

But where does the cosmic dust come from?

A group of astronomers has been able to follow cosmic dust being created in the aftermath of a supernova explosion. The new research not only shows that dust grains form in these massive explosions, but that they can also survive the subsequent shockwaves.

Stars initially draw their energy by fusing hydrogen into helium deep within their cores. But eventually a star will run out of fuel. After slightly messy physics, the star’s contracted core will begin to fuse helium into carbon, while a shell above the core continues to fuse hydrogen into helium.

The pattern continues for medium to high mass stars, creating layers of different nuclear burning around the star’s core. So the cycle of star birth and death has steadily produced and dispersed more heavy elements throughout cosmic history, providing the substances necessary for cosmic dust.

“The problem has been that even though dust grains composed of heavy elements would form in supernovae, the supernova explosion is so violent that the grains of dust may not survive,” said coauthor Jens Hjorth, head of the Dark Cosmology Center at the Niels Bohr Institute in a press release. “But cosmic grains of significant size do exist, so the mystery has been how they are formed and have survived the subsequent shockwaves.”

The team led by Christa Gall used ESO’s Very Large Telescope at the Paranal Observatory in northern Chile to observe a supernova, dubbed SN2010jl, nine times in the months following the explosion, and for a tenth time 2.5 years after the explosion. They observed the supernova in both visible and near-infrared wavelengths.

SN2010jl was 10 times brighter than the average supernova, making the exploding star 40 times the mass of the Sun.

“By combining the data from the nine early sets of observations we were able to make the first direct measurements of how the dust around a supernova absorbs the different colours of light,” said lead author Christa Gall from Aarhus University. “This allowed us to find out more about the dust than had been possible before.”

The results indicate that dust formation starts soon after the explosion and continues over a long time period.

The dust initially forms in material that the star expelled into space even before it exploded. Then a second wave of dust formation occurs, involving ejected material from the supernova. Here the dust grains are massive — one thousandth of a millimeter in diameter — making them resilient to any following shockwaves.

“When the star explodes, the shockwave hits the dense gas cloud like a brick wall. It is all in gas form and incredibly hot, but when the eruption hits the ‘wall’ the gas gets compressed and cools down to about 2,000 degrees,” said Gall. “At this temperature and density elements can nucleate and form solid particles. We measured dust grains as large as around one micron (a thousandth of a millimeter), which is large for cosmic dust grains. They are so large that they can survive their onward journey out into the galaxy.”

If the dust production in SN2010jl continues to follow the observed trend, by 25 years after the supernova explosion, the total mass of dust will have half the mass of the Sun.

The results have been published in Nature and are available for download here. Niels Bohr Institute’s press release and ESO’s press release are also available.

February 6, 2014December 23, 2015 by Elizabeth Howell

Surprise! Brown Dwarf Star Has Dusty Skies, Appearing Strangely Red

Artist's impression of brown dwarf ULAS J222711-004547, which has a very thick cloud layer of mineral dust. The dust is making the brown dwarf appear redder than its counterparts. Credit: Neil J. Cook, Centre for Astrophysics Research, University of Hertfordshire

Dust clouds on a brown dwarf or “failed star” are making it appear redder than its counterparts, new research reveals. Better studying this phenomenon could improve the weather forecast on these objects, which are larger than gas giant planets but not quite big enough to ignite nuclear fusion processes to become stars.

“These are not the type of clouds that we are used to seeing on Earth. The thick clouds on this particular brown dwarf are mostly made of mineral dust, like enstatite and corundum,” stated Federico Marocco, who led the research team and is an astrophysicist at the United Kingdom’s University of Hertfordshire.

Using the Very Large Telescope in Chile as well as data analysis, “not only have we been able to infer their presence, but we have also been able to estimate the size of the dust grains in the clouds,” he added.

The brown dwarf (known as ULAS J222711-004547) has an unusual concoction in its atmosphere of water vapor, methane, (likely) ammonia and these mineral particles. While scientists are only beginning to wrap their head around what’s going on in the atmosphere, they noted that the size of the dust grains can influence the color of the sky and make it turn redder.

Size comparison of stellar vs substellar objects. (Credit: NASA/JPL-Caltech/UCB).

“Being one of the reddest brown dwarfs ever observed, ULAS J222711-004547 makes an ideal target for multiple observations to understand how the weather is in such an extreme atmosphere,” stated Avril Day-Jones, an astrophysicist at the University of Hertfordshire who co-authored the paper.

“By studying the composition and variability in luminosity and colours of objects like this, we can understand how the weather works on brown dwarfs and how it links to other giant planets.”

You can read more about the research in the Monthly Notices of the Royal Astronomical Society or in preprint version on Arxiv.

And by the way, there’s been other exciting work lately in brown dwarfs; another group recently released the first weather map of another failed star (and we have some information on Universe Today on how that was done, too!) Also, there are other weird brown star atmospheres out there, as this 2013 find shows.

Source: Royal Astronomical Society

November 27, 2013December 23, 2015 by Tammy Plotner

Forging Stars – Peering Into Starbirth and Death

The Large Magellanic Cloud is one of the closest galaxies to our own. Astronomers have now used the power of the ESO’s Very Large Telescope to explore NGC 2035, one of its lesser known regions, in great detail. This new image shows clouds of gas and dust where hot new stars are being born and are sculpting their surroundings into odd shapes. But the image also shows the effects of stellar death — filaments created by a supernova explosion (left). Credit: ESO

Some 160,000 light years away towards the constellation of Dorado (the Swordfish), is an amazing area of starbirth and death. Located in our celestial neighbor, the Large Magellanic Cloud, this huge stellar forge sculpts vast clouds of gas and dust into hot, new stars and carves out ribbons and curls of nebulae. However, in this image taken by ESO’s Very Large Telescope, there’s more. Stellar annihilation also awaits and shows itself as bright fibers left over from a supernova event.

For southern hemisphere observers, one of our nearest galactic neighbors, the Large Magellanic Cloud, is a well-known sight and holds many cosmic wonders. While the image highlights just a very small region, try to grasp the sheer size of what you are looking at. The fiery forge you see is several hundred light years across, and the factory in which it is contained spans 14,000 light years. Enormous? Yes. But compared to the Milky Way, it’s ten times smaller.

Even at such a great distance, the human eye can see many bright regions where new stars are actively forming, such as the Tarantula Nebula. This new image, taken by ESO’s Very Large Telescope at the Paranal Observatory in Chile, explores an area cataloged as NGC 2035 (right), sometimes nicknamed the Dragon’s Head Nebula. But, just what are we looking at?

The Dragon’s Head is an HII region, more commonly referred to as an emission nebula. Here, young stars pour forth energetic radiation and illuminate the surrounding clouds. The radiation tears electrons away from the atoms contained within the gas. These atoms then gel again with other atoms and release light. Swirling in the mix is dark dust, which absorbs the light and creates deep shadows and create contrast in the nebula’s structure.

However, as we look deep into this image, there’s even more… a fiery finale. At the left of the photo you’ll see the results of one of the most violent events in the Universe – a supernova explosion. These troubled tendrils are all that’s left of what once was a star and its name is SNR 0536-67.6. Perhaps when it exploded, it was so bright that it was capable of outshining the Magellanic Cloud… fading away over the weeks or months that followed. However, it left a lasting impression!

Original Story Source: ESO Image Release.