A frosty landmark for planet and comet formation
18 July 2013
Harvard-Smithsonian Center for Astrophysics
Cambridge, Mass., USA
Tel: +1 617 495 7087
Leiden, The Netherlands
Tel: +31 6 4308 3291
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
“A snow line has been imaged in a far-off infant planetary system for the very first time. The snow line, located in the disc around the Sun-like star TW Hydrae, promises to tell us more about the formation of planets and comets, the factors that decide their composition, and the history of the Solar System. The results are published today in Science Express.
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have taken the first ever image of the snow line in an infant planetary system. On Earth, snow lines form at high altitudes where falling temperatures turn the moisture in the air into snow. This line is clearly visible on a mountain, where the snow-capped summit ends and the rocky face begins.
The snow lines around young stars form in a similar way, in the distant, colder reaches of the dusty discs from which planetary systems form. Starting from the star and moving outwards, water (H2O) is the first to freeze, forming the first snow line. Further out from the star, as temperatures drop, more exotic molecules can freeze and turn to snow, such as carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO). These different snows give the dust grains a sticky outer coating and play an essential role in helping the grains to overcome their usual tendency to break up in collisions, allowing them to become the crucial building blocks of planets and comets. The snow also increases how much solid matter is available and may dramatically speed up the planetary formation process.
Each of these different snow lines — for water, carbon dioxide, methane and carbon monoxide — may be linked to the formation of particular kinds of planets. Around a Sun-like star in a planetary system like our own, the water snow line would correspond to a distance between the orbits of Mars and Jupiter, and the carbon monoxide snow line would correspond to the orbit of Neptune.
The snow line spotted by ALMA is the first glimpse of the carbon monoxide snow line, around TW Hydrae, a young star 175 light-years away from Earth. Astronomers believe this budding planetary system shares many of the same characteristics of the Solar System when it was just a few million years old.
The team is composed of C. Qi (Harvard-Smithsonian Center for Astrophysics, USA), K. I. Öberg (Departments of Chemistry and Astronomy, University of Virginia, USA), D. J. Wilner (Harvard-Smithsonian Center for Astrophysics, USA), P. d’Alessio (Centro de Radioastronomía y Astroﬁsica, Universidad Nacional Autónoma de Mexico, Mexico), E. Bergin (Department of Astronomy, University of Michigan, USA), S. M. Andrews (Harvard-Smithsonian Center for Astrophysics, USA), G. A. Blake (Division of Geological and Planetary Sciences, California Institute of Technology, USA), M. R. Hogerheijde (Leiden Observatory, Leiden University, Netherlands) and E. F. van Dishoeck (Max Planck Institute for Extraterrestrial Physics, Germany).
See the full article here, with notes.
NRAO news release
Qi and Öberg were joint lead authors of this work.
ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
Visit ESO in Social Media-
THE BASIC TOOLS OF E.S.O.
Paranal Platform The VLT
NTT – New Technology Telescope
ALMA Atacama Large Millimeter/submillimeter Array
The European Extremely Large Telescope
VISTA (the Visible and Infrared Survey Telescope for Astronomy)
Atacama Pathfinder Experiment telescope (APEX)
ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.
ScienceSprings is powered by MAINGEAR computers