Portrait of a Dramatic Stellar Crib: ESO Releases 256 Million PixelImage of Immense Stellar Factory (Forwarded)

ESO Education and Public Relations Dept.

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For Immediate Release: 21 December 2006

ESO Press Photo 50/06

Portrait of a Dramatic Stellar Crib

ESO Releases 256 Million Pixel Image of Immense Stellar Factory

A new, stunning image of the cosmic spider, the Tarantula Nebula and its
surroundings, finally pays tribute to this amazing, vast and intricately
sculpted web of stars and gas. The newly released image, made with ESO's
Wide Field Imager on the 2.2-m ESO/MPG Telescope at La Silla, covers 1
square degree on the sky and could therefore contain four times the full
Moon.

Known as the Tarantula Nebula for its spidery appearance, the 30 Doradus
complex is a monstrous stellar factory. It is the largest emission nebula
in the sky, and can be seen far down in the southern sky at a distance of
about 170,000 light-years, in the southern constellation Dorado (The
Swordfish or the Goldfish). It is part of one of the Milky Way's
neighbouring galaxies, the Large Magellanic Cloud.

The Tarantula Nebula is thought to contain more than half a million times
the mass of the Sun in gas and this vast, blazing labyrinth hosts some of
the most massive stars known. The nebula owes its name to the arrangement
of its brightest patches of nebulosity, that somewhat resemble the legs of
a spider. They extend from a central 'body' where a cluster of hot stars
(designated 'R136') illuminates and shapes the nebula. This name, of the
biggest spiders on the Earth, is also very fitting in view of the gigantic
proportions of the celestial nebula -- it measures nearly 1,000
light-years across and extends over more than one third of a degree:
almost, but not quite, the size of the full Moon. If it were in our own
Galaxy, at the distance of another stellar nursery, the Orion Nebula
(1,500 light-years away), it would cover one quarter of the sky and even
be visible in daylight.

Because astronomers believe that most of the stars in the Universe were
formed in large and hectic nurseries such as the 30 Doradus region, its
study is fundamental. Early this year, astronomers took a new, wide look
at the spider and its web of filaments, using the Wide Field Imager on the
2.2-m MPG/ESO telescope located at La Silla, Chile, while studying the
dark clouds in the region. Dark clouds are enormous clouds of gas and
dust, with a mass surpassing a million times that of the Sun. They are
very cold, with temperatures about -260 degrees Celsius, and are difficult
to study because of the heavy walls of dust behind which they hide. Their
study is however essential, as it is in their freezing wombs that stars
are born.

Observing in four different bands, the astronomers made a mosaic of the
half-degree field of view of the instrument to obtain an image covering
one square degree. With each individual image containing 64 million
pixels, the resultant mosaic thus contained 4 times as many, or 256
million pixels! The observations were made in very good image quality, the
'seeing' being typically below 1 arcsecond.

The image is based on data collected through four filters, including two
narrow-band filters that trace hydrogen (red) and oxygen (green). The
predominance of green in the Tarantula is a result of the younger, hotter
stars in this region of the complex.

It would be easy to get lost in the meanderings of the filamentary
structures or get stuck in the web of the giant arachnid, as is easily
experienced with the zoom-in feature provided on the associated photo
page, and it is therefore difficult to mention all the unique objects to
be discovered. Deserving closer attention perhaps is the area at the
right-hand border of the Tarantula. It contains the remains of a star that
exploded and was seen with the unaided eye in February 1987, i.e. almost
20 years ago. Supernova SN 1987A, as it is known, is the brightest
supernova since the one observed by the German astronomer Kepler in 1604.
The supernova is known to be surrounded by a ring, which can be
distinguished in the image.

A little to the left of SN 1987A, another distinctive feature is apparent:
the Honeycomb Nebula. This characteristic bubble-like structure results
apparently from the interaction of a supernova explosion with an existing
giant shell, which was itself generated by the combined action of strong
winds from young, massive stars and supernova explosions.

The image is based on observations carried out by João Alves (Calar Alto,
Spain), Benoit Vandame and Yuri Bialetski (ESO) with the Wide Field Imager
(WFI) at the 2.2-m telescope on La Silla. The colour composite was made by
Bob Fosbury (ST-EcF).

The reduced data used to make this image are released as Advanced Data
Products (ADP) by the Virtual Observatory Systems Department of ESO. More
detail on how to access the data are available from the 30 Doradus ADP
page.

National contacts for the media:

Belgium: Dr. Rodrigo Alvarez, +32-2-474 70 50
Finland: Ms. Riitta Tirronen, +358 9 7748 8369
Denmark: Dr. Michael Linden-Vørnle, +45-33-18 19 97
France: Dr. Daniel Kunth, +33-1-44 32 80 85
Germany: Dr. Jakob Staude, +49-6221-528229
Italy: Dr. Leopoldo Benacchio, +39-347-230 26 51
The Netherlands: Ms. Marieke Baan, +31-20-525 74 80
Portugal: Prof. Teresa Lago, +351-22-089 833
Sweden: Dr. Jesper Sollerman, +46-8-55 37 85 54
Switzerland: Dr. Martin Steinacher, +41-31-324 23 82
United Kingdom: Mr. Peter Barratt, +44-1793-44 20 25

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