ESO 40/08 - Press Photo

11 November 2008
For immediate release

APEX reveals glowing stellar nurseries

Illustrating the power of submillimetre-wavelength astronomy, an APEX image reveals how an expanding bubble of ionised gas about ten light-years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars. Submillimetre light is the key to revealing some of the coldest material in the Universe, such as these cold, dense clouds.

The region, called RCW120, is about 4200 light years from Earth, towards the constellation of Scorpius. A hot, massive star in its centre is emitting huge amounts of ultraviolet radiation, which ionises the surrounding gas, stripping the electrons from hydrogen atoms and producing the characteristic red glow of so-called H-alpha emission.

As this ionised region expands into space, the associated shock wave sweeps up a layer of the surrounding cold interstellar gas and cosmic dust. This layer becomes unstable and collapses under its own gravity into dense clumps, forming cold, dense clouds of hydrogen where new stars are born. However, as the clouds are still very cold, with temperatures of around -250˚ Celsius, their faint heat glow can only be seen at submillimetre wavelengths. Submillimetre light is therefore vital in studying the earliest stages of the birth and life of stars.

The submillimetre-wavelength data were taken with the LABOCA camera on the 12-m Atacama Pathfinder Experiment (APEX) telescope, located on the 5000 m high plateau of Chajnantor in the Chilean Atacama desert. Thanks to LABOCA's high sensitivity, astronomers were able to detect clumps of cold gas four times fainter than previously possible. Since the brightness of the clumps is a measure of their mass, this also means that astronomers can now study the formation of less massive stars than they could before.

The plateau of Chajnantor is also where ESO, together with international partners, is building a next generation submillimetre telescope, ALMA, the Atacama Large Millimeter/submillimeter Array. ALMA will use over sixty 12-m antennas, linked together over distances of more than 16 km, to form a single, giant telescope.

APEX is a collaboration between the Max-Planck-Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. The telescope is based on a prototype antenna constructed for the ALMA project. Operation of APEX at Chajnantor is entrusted to ESO.

Contact

Douglas Pierce-Price
ESO ALMA/APEX Public Information Officer
ESO, Garching, Germany
Phone: +49 89 3200 6759
E-mail: dpiercep (at) eso.org



ESO Press Officer in Chile: Valentina Rodriguez - +56 2 463 3123 - vrodrigu@eso.org

National contacts for the media: Belgium - Dr. Rodrigo Alvarez +32-2-474 70 50 rodrigo.alvarez@oma.be Czech Republic - Pavel Suchan +420 267 103 040 suchan@astro.cz Denmark - Dr. Michael Linden-Vørnle +45-33-18 19 97 mykal@tycho.dk Finland - Ms. Riitta Tirronen +358 9 7748 8369 riitta.tirronen@aka.fi France - Dr. Daniel Kunth +33-1-44 32 80 85 kunth@iap.fr Germany - Dr. Jakob Staude +49-6221-528229 staude@mpia.de Italy - Dr. Leopoldo Benacchio +39-347-230 26 51 benacchio@inaf.it

The Netherlands - Dr. Marieke Baan +31-20-525 74 80 mbaan@science.uva.nl Portugal - Prof. Teresa Lago +351-22-089 833 mtlago@astro.up.pt Spain - Dr. Miguel Mas-Hesse +34918131196 mm@laeff.inta.es Sweden - Dr. Jesper Sollerman +46-8-55 37 85 54 jesper@astro.su.se Switzerland - Dr. Martin Steinacher +41-31-324 23 82 martin.steinacher@sbf.admin.ch United Kingdom - Mr. Peter Barratt +44-1793-44 20 25 peter.barratt@stfc.ac.uk USA - Dr. Paola Rebusco +1-617-308-2397 prebusco@eso.org