Hubble Catches Celestial Prawn Drifting Through the Cosmic Deep

Prawn Nebula

Main Image Credit: NASA, ESA, and J. Tan (Chalmers University of Technology); Processing; Gladys Kober (NASA/Catholic University of America)

The Prawn Nebula is a massive stellar nursery located in the constellation Scorpius, about 6,000 light years from Earth. Though the nebula stretches 250 light-years and covers a space four times the size of the full moon, it emits light primarily in wavelengths the human eye cannot detect, making it extremely faint to earthbound viewers. Hubble’s gaze, however, shows a small section of the nebula here in both visible and invisible infrared light, capturing dazzling detail of the nebula’s structure, including bright areas of glowing gas.

The Prawn Nebula, also known as IC 4628, is an emission nebula, which means its gas has been energized, or ionized, by the radiation of nearby stars. The radiation from these massive stars strips electrons from the nebula’s hydrogen atoms. As the energized electrons revert from their higher-energy state to a lower-energy state by recombining with hydrogen nuclei, they emit energy in the form of light, causing the nebula’s gas to glow. In this image, red indicates the presence of ionized iron (Fe II) emission.

This Hubble Space Telescope image was captured as part of a survey of massive- and intermediate-size “protostars,” or newly forming stars. Astronomers used the infrared sensitivity of Hubble’s Wide Field Camera 3 to look for hydrogen ionized by ultraviolet light ionized by the protostars, jets from the stars, and other features.

The Prawn Nebula lies south of the star Antares in the constellation Scorpius, the Scorpion. Hubble's focused view captures just a small portion of the vast star-forming region. Credits: NASA, ESA, J. Tan (Chalmers University of Technology), and ESO; Processing; Gladys Kober (NASA/Catholic University of America) Main Image Credit: NASA, ESA, and J. Tan (Chalmers University of Technology); Processing; Gladys Kober (NASA/Catholic University of America)

Media Contact:

Claire Andreoli
NASA's Goddard Space Flight Center
301-286-1940

Editor: Andrea Gianopoulos

Source: NASA/Hubble

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Cosmic Recycling

PR Image eso1535a
The Prawn Nebula in close-up

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The Prawn Nebula IC 4628 in the constellation of Scorpius

Videos

 

PR Video eso1535a

Zooming in on the Prawn Nebula

PR Video eso1535b

A close-up look at the Prawn Nebula

Dominating this image is part of the gigantic nebula Gum 56, illuminated by the hot bright young stars that were born within it. For millions of years stars have been created out of the gas in this nebula, material which is later returned to the stellar nursery when the aging stars either expel their material gently into space or eject it more dramatically as supernova explosions. This image was taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile as part of ESO’s Cosmic Gems programme. 

Dominating this image is part of the gigantic nebula Gum 56, illuminated by the hot bright young stars that were born within it. For millions of years stars have been created out of the gas in this nebula, material which is later returned to the stellar nursery when the aging stars either expel their material gently into space or eject it more dramatically as supernova explosions. This image was taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile as part of ESO’s Cosmic Gems programme.

Deeply immersed in this huge stellar nursery are three clusters of hot young stars — only a few million years old — which glow brightly in ultraviolet light. It is the light from these stars that causes the nebula’s gas clouds to glow. The radiation strips electrons from atoms — a process known as ionisation — and when they recombine they release energy in the form of light. Each chemical element emits light in characteristic colours and the large clouds of hydrogen in the nebula are the cause of its rich red glow.

Gum 56 — also known as IC 4628 or by its nickname, the Prawn Nebula — is named after the Australian astronomer Colin Stanley Gum, who, in 1955, published a catalogue of H II regions. H II regions such as Gum 56 are huge, low density clouds containing a large amount of ionised hydrogen.

A large portion of the ionisation in Gum 56 is done by two O-type stars, which are hot blue–white stars, also known as blue giants because of their colour [1]. This type of star is rare in the Universe as the very large mass of blue giants means that they do not live for long. After only roughly a million years these stars will collapse in on themselves and end their lives as supernovae, as will many of the other massive stars within the nebula.

Besides the many newborn stars nestled in the nebula, this large region is still filled with enough dust and gas to create an even newer generation of stars. The regions of the nebula giving birth to new stars are visible in the image as dense clouds. The material forming these new stars includes the remains of the most massive stars from an older generation that have already ended their lives and ejected their material in violent supernova explosions. Thus the cycle of stellar life and death continues.

Given the two very unusual blue giants in this area and the prominence of the nebula at infrared and radio wavelengths, it is perhaps surprising that this region has been comparatively little studied as yet by professional astronomers. Gum 56 has a diameter of around 250 light-years, but despite its huge size it has also often been overlooked by visual observers due to its faintness, and because most of the light it emits is at wavelengths not visible to the human eye.

The nebula is at a distance of about 6000 light-years from Earth. In the sky it can be found in the constellation Scorpius (The Scorpion) where it has a projected size which is four times the size of the full Moon [2].

This image, which only captures a part of the nebula, was taken with the 2.2-metre MPG/ESO telescope using the Wide Field Imager (WFI) camera as part of the ESO Cosmic Gems programme. The programme makes use of telescope time that cannot be used for science observations to produce images of interesting, intriguing or visually attractive objects. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.


Notes

[1] Note that these stars fall outside the field of view of this particular image and do not appear in the picture.

[2] A wide-angle view of the Prawn Nebula taken by the VLT Survey Telescope was published earlier (eso1340a).
 

More Information

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


Links 

• Photos of the MPG/ESO.2.2-metre telescope
• Photos taken with the MPG/ESO.2.2-metre telescope

Contacts

Richard Hook
ESO education and Public Outreach Department
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org

Source: ESO

Young Stars Cooking in the Prawn Nebula

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Detailed view of the Prawn Nebula from ESO's VST

PR Image eso1340b

The Prawn Nebula from ESO's VST (wide crop)

PR Image eso1340c

Excerpts from a view of the Prawn Nebula from ESO's VST 

PR Image eso1340d

The Prawn Nebula IC 4628 in the constellation of Scorpius

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Videos

PR Video eso1340a

Zooming in on the Prawn Nebula

PR Video eso1340b

A close-up look at the Prawn Nebula from ESO’s VST

The glowing jumble of gas clouds visible in this new image make up a huge stellar nursery nicknamed the Prawn Nebula. Taken using the VLT Survey Telescope at ESO’s Paranal Observatory in Chile, this may well be the sharpest picture ever taken of this object. It shows clumps of hot new-born stars nestled in among the clouds that make up the nebula.

Located around 6000 light-years from Earth in the constellation of Scorpius (The Scorpion), the nebula formally known as IC 4628 is a huge region filled with gas and clumps of dark dust. These gas clouds are star-forming regions, producing brilliant hot young stars. In visible light, these stars appear as a blue-white colour, but they also emit intense radiation in other parts of the spectrum — most notably in the ultraviolet [1].

It is this ultraviolet light from the stars that causes the gas clouds to glow. This radiation strips electrons from hydrogen atoms, which then later recombine and release energy in the form of light. Each chemical element emits light at characteristic colours when this process occurs, and for hydrogen the predominant colour is red. IC 4628 is an example of an HII region [2].

The Prawn Nebula is around 250 light-years across, covering an area of sky equivalent to four times that of the full Moon. Despite this huge size it has been often overlooked by observers due to its faintness and because most of its light is emitted at wavelengths where the human eye is not sensitive. The nebula is also known as Gum 56, after the Australian astronomer Colin Gum, who published a catalogue of HII regions in 1955.

Over the last few million years this region of sky has formed many stars, both individually and in clusters. There is a large scattered star cluster named Collinder 316 which extends over most of this image. This cluster is a part of a much larger gathering of very hot and luminous stars. Also visible are many dark structures or cavities, where interstellar matter has been blown away by the powerful winds generated by the nearby hot stars.

This image was taken by the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile. The VST is the largest telescope in the world designed for surveying the sky in visible light. It is a state-of-the-art 2.6-metre telescope built around the OmegaCAM camera that contains 32 CCD detectors that together create 268-megapixel images. This new 24 000-pixel-broad image is a mosaic of two such images and is one of the largest single images released by ESO so far.

The picture forms part of a detailed public survey of a large part of the Milky Way called VPHAS+ that is using the power of the VST to search for new objects such as young stars and planetary nebulae. The survey will also provide the best images yet taken of many huge glowing star formation regions, such as the one pictured here.

The very sharp VST images were further enhanced to bring out the colour by including additional high quality imaging through other filters taken by Martin Pugh, a very skilled amateur astronomer observing from Australia using 32-centimetre and 13-centimetre telescopes [3].

This press release represents a milestone — it is the 1000th press release issued by ESO. The first one appeared in late 1985 and featured a picture of Halley's Comet. They are all available online.

Notes

[1] This is the same kind of radiation that causes unprotected human skin to burn when exposed to too much direct sunlight. But the Earth’s atmosphere shields life on the surface from most ultraviolet radiation and only longer wavelengths (between about 300 and 400 nanometres) reach the ground and cause tanning and burning of human skin. Some of the ultraviolet radiation emitted by very hot stars in HII regions is at the much shorter wavelengths (shorter than 91.2 nanometres) that can ionise hydrogen.

[2] Astronomers use the term “HII” (pronounced “aitch-two”) to refer to ionised hydrogen, and “HI” (aitch-one) for atomic hydrogen. A hydrogen atom consists of an electron bound to a proton; in an ionised gas, atoms are split into freely-moving electrons and positive ions — in this case the positive ions are just single protons.

[3] More details of his observations can be found at Martin Pugh’s information page on this object.

More information

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

• The VPHAS+ survey
• Photos of the VST
• Photos taken with the VST

Contacts

Richard Hook
ESO, La Silla, Paranal, E-ELT and Survey Telescopes Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org