ESO Archives

April 10, 2013December 23, 2015 by Tammy Plotner

Looking Into The Green Eye Of Planetary Nebula IC 1295

This intriguing picture from ESO’s Very Large Telescope shows the glowing green planetary nebula IC 1295 surrounding a dim and dying star. It is located about 3300 light-years away in the constellation of Scutum (The Shield). This is the most detailed picture of this object ever taken. Credit: ESO

Located on Cerro Paranal in the Atacama Desert of northern Chile, the ESO’s Very Large Telescope was busy using the FORS instrument (FOcal Reducer Spectrograph) to achieve one of the most detailed observations ever taken off a lonely, green planetary nebula – IC 1295. Exposures taken through three different filters which enhanced blue light, visible green light, and red light were melded together to make this 3300 light year distant object come alive.

Located in the constellation of Scutum, this jewel in the “Shield” is a miniscule star that’s at the end of its life. Much like our Sun will eventually become, this white dwarf star is softly shedding its outer layers, like an unfolding flower in space. It will continue this process for a few tens of thousands of years, before it ends, but until then IC 1295 will remain something of an enigma.

“The range of shapes observed up to today has been reproduced by many theoretical works using arguments such as density enhancements, magnetic fields, and binary central systems. Despite this, no complete agreement between models and properties of a given morphological group has been achieved. One of the main reasons for this is selection criteria and completeness of studied samples.” say researchers at Georgia State University. “The samples are usually limited by available images in few bands such as Ha, [NII] and [OIII]. Of course they are also limited by distance, since the further away the object is, the harder it is to resolve its structure. Even with the modern telescopes, obtaining a truly complete sample is far from being achieved.”

Why is this common deep space object like IC 1295 such a mystery? Blame it on its structure. It is comprised of multiple shells.- gaseous layers which once were the star’s atmosphere. As the star aged, its core became unstable and it erupted in unexpected releases of energy – like expansive blisters breaking open. These waves of gas are then illuminated by the ancient star’s ultraviolet radiation, causing it to glow. Each chemical acts as a pigment, resulting in different colors. In the case of IC 1295, the verdant shades are the product of ionised oxygen.

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This video sequence starts with a broad panorama of the Milky Way and closes in on the small constellation of Scutum (The Shield), home to many star clusters. The final detailed view shows the strange green planetary nebula IC 1295 in a new image from ESO’s Very Large Telescope. This faint object lies close to the brighter globular star cluster NGC 6712. Credit: ESO/Nick Risinger (skysurvey.org)/Chuck Kimball. Music: movetwo

However, green isn’t the only color you see here. At the heart of this planetary nebula beats a bright, blue-white stellar core. Over the course of billions of years, it will gently cool – becoming a very faint, white dwarf. It’s just all part of the process. Stars similar to the Sun, and up to eight times as large, are all theorized to form planetary nebulae as they extinguish. How long does a planetary nebula last? According to astronomers, it’s a process that could be around 8 to 10 thousand years.

“Athough planetary nebulae (PNe) have been discovered for over 200 years, it was not until 30 years ago that we arrived at a basic understanding of their origin and evolution.” says Sun Kwok of the Institute of Astronomy and Astrophysics. “Even today, with observations covering the entire electromagnetic spectrum from radio to X-ray, there are still many unanswered questions on their structure and morphology.”

Original Story Source: ESO Photo Release.

February 28, 2013December 23, 2015 by Nancy Atkinson

First Direct Observation of a Nearby Protoplanet

This image from the NACO system on ESO’s Very Large Telescope shows a candidate protoplanet in the disc of gas and dust around the young star HD100546. Credit: ESO.

Astronomers have taken what is likely the first-ever direct image of a planet that is still undergoing its formation, embedded in its “womb” of gas and dust. The protoplanet, about the size of Jupiter, is in the disc surrounding a young star, HD 100546, located 335 light-years from Earth.

If this discovery is confirmed, astronomers say this it will greatly improve our understanding of how planets form and allow astronomers to test the current theories against an observable target.

“So far, planet formation has mostly been a topic tackled by computer simulations,” said Sascha Quanz, from ETH Zurich in Switzerland, who led an international team using the Very Large Telescope to make the observations. “If our discovery is indeed a forming planet, then for the first time scientists will be able to study the planet formation process and the interaction of a forming planet and its natal environment empirically at a very early stage.”

The protoplanet appears as a faint blob in the circumstellar disc of HD 100546, a well-studied star, and astronomers have already discovered other protoplanets orbiting this star. In 2003, astronomers used a technique called “nulling interferometry” to reveal not only the planetary disk, but also discovered a gap in the disk, where a Jupiter-like planet is probably forming about six times farther form the star than Earth is from the Sun. This newly found planet candidate is located in the outer regions of the system, about ten times further out.

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The team used the VLT along with a near-infrared coronograph in an adaptive optics instrument called NACO, which enabled them to suppresses the bright light of the star, combined with pioneering data analysis techniques.

The current theory of planet formation is based mostly on observations of our own solar system. Since 1995, when the first exoplanet around a Sun-like star was discovered, several hundred planetary systems have been found, opening up new opportunities for scientists studying planetary formation. But until now, none have been “caught in the act” in the process of being formed, while still embedded in the disc of material around their young parent star.

This composite image shows a view from the NASA/ESA Hubble Space Telescope (left) and from the NACO system on ESO’s Very Large Telescope (right) of the gas and dust around the young star HD 100546. The Hubble visible-light image shows the outer disc of gas and dust around the star. The new infrared VLT picture of a small part of the disc shows a candidate protoplanet. Both pictures were taken with a special coronagraph that suppresses the light from the brilliant star. The position of the star is marked with a red cross in both panels. Credit: ESO/NASA/ESA/Ardila et al.

But in studying the disc around HD 100546, astronomers have spotted several features that support the current theory that giant planets grow by capturing some of the gas and dust that remains after the formation of a star. They have seen structures in the dusty circumstellar disc, which could be caused by interactions between the planet and the disc, as well as indications that the surroundings of the protoplanet are being heated up by the formation process.

The astronomers are doing follow-up observations to confirm the discovery, as it is possible that the detected signal could have come from an unrelated background source, or it could possibly be a fully formed planet which was ejected from its original orbit closer to the star. But the researchers say the most likely explanation is that this is actually the first protplanet that has been directly imaged.

Source: ESO

February 13, 2013December 23, 2015 by Nancy Atkinson

Cosmic Ink-blot Test: Can You See the Gecko in Space?

This image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile, shows the bright star cluster NGC 6520 and its neighbour, the strangely shaped dark cloud Barnard 86. This cosmic pair is set against millions of glowing stars from the brightest part of the Milky Way — a region so dense with stars that barely any dark sky is seen across the picture. — Millions of glowing stars from the brightest part of the Milky Way — a region so dense with stars that barely any dark sky is seen across the picture. Credit: ESO

A small, isolated dark nebula known as a Bok globule was described as “a drop of ink on the luminous sky” by its discoverer, astronomer Edward Emerson Barnard. Through a small telescope, the object seen here, Barnard 86, does appear as though someone may have dropped a blob of dark ink on the telescope lens. Or perhaps it appears as a spot where there are no stars, or a window into a patch of distant, clearer sky. However, this object is actually in the foreground of the star field — a cold, dark, dense cloud made up of small dust grains that block starlight and make the region appear opaque. It is thought to have formed from the remnants of a molecular cloud that collapsed to form the nearby star cluster NGC 6520, seen just to the left of Barnard 86 in this image.

Some say Barnard 86 looks like a gecko … can you see the resemblance?

This image was taken with the Wide Field Imager on the MPG/ESO 2.2-meter telescope at ESO’s La Silla Observatory in Chile. This cosmic pair is set against millions of glowing stars from the brightest part of the Milky Way — a region so dense with stars that barely any dark sky is seen across the picture.

It is located in the constellation of Sagittarius in one of the richest star fields in the whole sky, the Large Sagittarius Star Cloud. The huge number of stars that light up this region dramatically emphasize the blackness of dark clouds like Barnard 86.

For more info on this image, see this ESO page.

February 8, 2013December 23, 2015 by Jason Major

A Cosmic Seagull’s Star-Studded Wings

Bright stars and vast clouds of dust and gas illuminate the “wings” of the Seagull Nebula (ESO)

These glowing red clouds are just a small part of the wings of an enormous bird — the Seagull Nebula, a band of gas and dust 3,400 light-years away that shines from UV light radiating from hot newborn stars.

This image was made from observations with the MPG/ESO 2.2-meter telescope at the ESO La Silla Observatory in Chile. See the full wide-field view of the Seagull Nebula below.

Wide-field view of the Seagull Nebula. The white box is the area seen at top. North is up in this view. (ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin)

The Seagull Nebula (IC 2177) is a vaguely bird-shaped region of gas and dust clouds located between the constellations Canis Major and Monoceros. The detail image at the top of this article is located along the upper edge of the gull’s lower wing, and is separately cataloged as Sharpless 2-296.

The bright red glow is the result of ionized hydrogen energized by the radiation from the several hot, bright young stars seen in the image. H II regions like the Seagull Nebula are signs of ongoing star formation in a galaxy — in a spiral galaxy like our Milky Way, these dust clouds are scattered throughout the arms. In fact, it was observations of such nebulae in the 1950s by Stewart Sharpless that helped determine the spiral structure of the Galaxy.

The silhouettes of dark, dense clouds closer to Earth block the red hydrogen glow from more distant areas of Sharpless 2-296.

Dark Nebula Hides Star Birth

A new image from ESO shows a dark cloud where new stars are forming along with a cluster of brilliant stars that have already emerged from their dusty stellar nursery. Credit: ESO/F. Comeron.

Dark nebulas, or dark clouds in space are intriguing because they appear to be “holes” in the sky where there aren’t any stars. But they really are just blocking our view. Also called absorption nebulas, these dark, smokey clouds of gas and dust block light from the regions of space behind it. This new image from ESO shows a dark cloud called Lupus 3 along with a cluster of brilliant stars.

While the dark cloud and the bright cluster of stars appear to be very different, they are in fact closely linked. The cloud contains huge amounts of cool cosmic dust and is a nursery where new stars are being born. We likely wouldn’t be able to see the absorption nebula unless it was silhouetted against the much brighter region of space produced by the star cluster, since absorption nebulas do not create their own light.

As light from space reaches an absorption nebula it is absorbed by it and does not pass through. It is likely that the Sun formed in a similar star formation region more than four billion years ago. The stars seen here are probably less than one million years old.

Lupus 3 lies about 600 light-years from Earth in the constellation of Scorpius. The dark section shown here is about five light-years across.

The new picture was taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile and is the best image ever taken in visible light of this little-known object.

Source: ESO

January 11, 2013April 26, 2016 by Jason Major

So. Many. Stars…

Infrared image of globular cluster 47 Tucanae (NGC 104) captured by ESO’s VISTA telescope.

“My god, it’s full of stars!” said Dave Bowman in the movie 2010 as he entered the monolith, and one could imagine that the breathtaking view before him looked something like this.

Except this isn’t science fiction, it’s reality — this is an image of globular cluster 47 Tucanae taken by the European Southern Observatory’s VISTA telescope at the Paranal Observatory in Chile. It reveals in stunning detail a brilliant collection of literally millions of stars, orbiting our Milky Way galaxy at a distance of 15,000 light-years.

The full image can be seen below.

47 Tucanae (also known as NGC 104) is located in the southern constellation Tucana. It’s bright enough to be seen without a telescope and, even though it’s very far away for a naked-eye object, covers an area about the size of the full Moon.

In reality the cluster is 124 light-years across.

Although globular clusters like 47 Tucanae are chock-full of stars — many of them very old, even as stars go — they are noticeably lacking in clouds of gas and dust. It’s thought that all the gaseous material has long since condensed to form stars, or else has been blown away by radiation and outbursts from the cluster’s exotic inhabitants.

At the heart of 47 Tucanae lie many curious objects like powerful x-ray sources, rapidly-spinning pulsars, “vampire” stars that feed on their neighbors, and strange blue stragglers — old stars that somehow manage to stay looking young. (You could say that a globular cluster is the cosmic version of a trashy reality show set in Beverly Hills.)

Red giants can be seen surrounding the central part of the cluster, old bloated stars that are running out of fuel, their outer layers expanding.

The background stars in the image are part of the Small Magellanic Cloud, which was in the distance behind 47 Tucanae when this image was taken.

VISTA is the world’s largest telescope dedicated to mapping the sky in near-infrared wavelengths. Located at ESO’s Paranal Observatory in Chile, VISTA is revealing new views of the southern sky. Read more about the VISTA survey here.

Image credit: ESO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit

December 17, 2012December 23, 2015 by Jason Major

The Paranal and the Shadow of the Earth

This beautiful photo, taken by ESO photo ambassador Babak Tafreshi, shows the European Southern Observatory’s Very Large Telescope array and VISTA telescope atop the peaks of the Cerro Paranal in Chile’s Atacama Desert. In the distance the Earth’s shadow extends outward toward the horizon, divided from the bluer daytime sky by the dusky pink “Belt of Venus.”

At an altitude of 2,635 meters (8,645 feet) the Paranal looks down onto a sea of clouds covering the Pacific Ocean, visible at right, whose shores lie 12 km in the distance.

Image credit: ESO/B. Tafreshi (twanight.org)

November 21, 2012December 23, 2015 by Jason Major

Makemake’s Mysteriously Missing Atmosphere

Artist’s impression of the surface of Makemake, a dwarf planet beyond Pluto (ESO/L. Calçada/Nick Risinger)

It turns out there’s no air up there: the distant dwarf planet Makemake is surprisingly lacking in an atmosphere, according to findings made by astronomers using telescopes at ESO’s La Silla and Paranal observatories.

An international team of astronomers used the mountaintop telescopes to observe Makemake as it passed in front of a faint background star in April 2011, a brief stellar occultation that lasted only about a minute. By watching how the starlight was blotted out by Makemake, measurements could be made of the dwarf planet’s size, mass and atmosphere — or, in this case, its lack thereof… a finding which surprised some scientists.

“As Makemake passed in front of the star and blocked it out, the star disappeared and reappeared very abruptly, rather than fading and brightening gradually. This means that the little dwarf planet has no significant atmosphere,” said team leader José Luis Ortiz of the Instituto de Astrofísica de Andalucía in Spain. “It was thought that Makemake had a good chance of having developed an atmosphere — that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies.”

First discovered in 2005, Makemake is an icy dwarf planet about 2/3 the diameter of Pluto — and 19 AU further from the Sun (but not nearly as far as the larger Eris, which is over 96 AU away.) It was thought that Makemake might have a tenuous, seasonal atmosphere similar to what has been found on Pluto, but it now appears that it does not… at least not in any large-scale, global form.

Due to its small size, sheer distance and apparent lack of moons, making scientific observations of Makemake has been a challenge for astronomers. The April 2011 occultation allowed measurements to be made — even if only for a minute — that weren’t possible before, including first-ever calculations of the dwarf planet’s density and albedo.

As it turns out, Makemake’s albedo is about 0.77 — comparable to that of dirty snow… a reflectivity higher than Pluto’s but lower than that of Eris. Its density is estimated to be 1.7 ± 0.3 g/cm³, indicating a composition of mostly ice with some rock.

“Our new observations have greatly improved our knowledge of one of the biggest [icy bodies], Makemake — we will be able to use this information as we explore the intriguing objects in this region of space further,” said Ortiz.

New Rogue Planet Found, Closest to our Solar System

This artist’s impression shows the free-floating planet CFBDSIR J214947.2-040308.9. Credit: ESO/L. Calçada/P. Delorme/Nick Risinger/R. Saito/VVV Consortium

Rogue planets – also known as free floating planets – are pretty intriguing. They are not orbiting a star but instead are wandering through the galaxy, having been either forcibly ejected from a solar system or having formed very early on in the Universe. While only a handful of these planets have been actually found, astronomers estimate these vagrant worlds could vastly outnumber stars. In fact, it’s been suggested there could be 100,000 times more rogue planets than stars in our Milky Way galaxy alone!

The latest rogue world to be found is exciting in that it is the closest such object to our Solar System so far. At a distance of about 100 light-years, its comparative proximity, along with the absence of a bright star very close to it, has allowed the team to study its atmosphere in great detail. Astronomers say this object gives them a preview of the exoplanets that future instruments will be able to find – and potentially take image of — around stars other than the Sun. But the planet also seems to be loosely tied to a roving group of stars, called the AB Doradus Moving Group.

The new rogue planet, with the ungainly name of CFBDSIR J214947.2-040308.9 (CFBDSIR2149 for short), was found using the Very Large Telescope and the Canada-France-Hawaii Telescope. The astronomers, led by Philippe Delorme from the Institut de planétologie et d’astrophysique de Grenoble, CNRS/Université Joseph Fourier, France, are calling the object a rogue planet candidate for now, as they want to study it further to confirm its free-floating status.

Moving star systems are equally intriguing. The AB Doradus Moving Group is the closest such group to our Solar System, and the stars drift through space together in a pack. They are thought to have formed at the same time. If the new rogue planet actually is associated with this moving group, astronomers say it will be possible to deduce much more about it, including its temperature, mass, and what its atmosphere is made of. There remains a small probability that the association with the moving group is by chance.

The link between the new object and the moving group is the vital clue that allows astronomers to find the age of the newly discovered object. Without knowing its age, it’s not possible to know whether it is really a planet, or a brown dwarf, a “failed” star that lack the bulk to trigger the reactions that make stars shine.

This is the first isolated planetary mass object ever identified in a moving group, and the association with this group makes it the most interesting free-floating planet candidate identified so far.

This closeup of an image captured by the SOFI instrument on ESO’s New Technology Telescope at the La Silla Observatory shows the free-floating planet CFBDSIR J214947.2-040308.9 in infrared light. This object, which appears as a faint blue dot at the centre of the picture, is the closest such object to the Solar System. Credit: ESO/P. Delorme.

“Looking for planets around their stars is akin to studying a firefly sitting one centimetre away from a distant, powerful car headlight,” said Delorme. “This nearby free-floating object offered the opportunity to study the firefly in detail without the dazzling lights of the car messing everything up.”

Free-floating objects like CFBDSIR2149 are thought to form either as normal planets that have been booted out of their home systems, or as lone objects like the smallest stars or brown dwarfs. In either case these objects are intriguing — either as planets without stars, or as the tiniest possible objects in a range spanning from the most massive stars to the smallest brown dwarfs.

“These objects are important, as they can either help us understand more about how planets may be ejected from planetary systems, or how very light objects can arise from the star formation process,” says Philippe Delorme. “If this little object is a planet that has been ejected from its native system, it conjures up the striking image of orphaned worlds, drifting in the emptiness of space.”

If CFBDSIR2149 is not associated with the AB Doradus Moving Group, the astronomers say it is trickier to be sure of its nature and properties, and it may instead be characterized as a small brown dwarf. Both scenarios represent important questions about how planets and stars form and behave.

“Further work should confirm CFBDSIR2149 as a free-floating planet,” said Delorme. “This object could be used as a benchmark for understanding the physics of any similar exoplanets that are discovered by future special high-contrast imaging systems, including the SPHERE instrument that will be installed on the VLT.”

This video shows an artist’s impression of the free-floating planet CFBDSIR J214947.2-040308.9. In the first part of the sequence the planet appears as a dark disc in visible light, silhouetted against the star clouds of the Milky Way. This is the closest such object to the Solar System and the most exciting candidate free-floating planet found so far. It does not orbit a star and hence does not shine by reflected light; the faint glow it emits can only be detected in infrared light. In the final sequence we see an infrared view of the object with the central parts of the Milky Way as seen by the VISTA infrared survey telescope as background. The object appears blueish in this near-infrared view because much of the light at longer infrared wavelengths is absorbed by methane and other molecules in the planet’s atmosphere. In visible light the object is so cool that it would only shine dimly with a deep red colour when seen close-up.

Read the team’s research paper here (pdf).

Source: ESO

November 12, 2012December 23, 2015 by Nancy Atkinson

Astrophoto: Deep Sky Treasury

The view of the Paranal Observatory: Credit: ESO/Babak Tafreshi

A new image captures the stunning view of the night sky over ESO’s Paranal Observatory, with a treasury of deep-sky objects. The image was taken by Babak Tafreshi, an astronomer, journalist and director of The World at Night (TWAN).

It shows the Carina Nebula, glowing intensely red in the middle of the image. Below Carina is the the Wishing Well Cluster (NGC 3532); then to the right is the Lambda Centauri Nebula (IC 2944) – which is also called the Running Chicken Nebula. Above this nebula and slightly to the left is the Southern Pleiades (IC 2632), an open cluster of stars that is similar to its more familiar northern namesake.

In the foreground, is three of the four Auxiliary Telescopes (ATs) of the Very Large Telescope Interferometer (VLTI).

See more information about this image from ESO.

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