Planeta nou nascuta din gaz…

VIDEO. Premieră pentru lumea ştiinţifică. Au fost capturate primele imagini cu naşterea unei planete

Observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope of the disc of gas and cosmic dust around the young star HD 142527, showing vast streams of gas flowing across the gap in the disc. Credit:  ALMA (ESO/NAOJ/NRAO), S. Casassus et al.

ESO / Planet-Forming Gas Streams HD 142527 | ESO / ALMA
{Artist’s impression} Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope have seen a key stage in the birth of giant planets for the first time. Vast streams of gas are flowing across a gap in the disc of gap in the disc around a young star. These are the first direct observations of such streams, which are expected to be created by giant planets guzzling gas as they grow. The result is published on 2 January 2013 in the journal Nature.
The international team of astronomers studied the young star HD 142527, over 450 light-years from Earth, which is surrounded by a disc of gas and cosmic dust — the remains of the cloud from which the star formed. The dusty disc is divided into an inner and an outer part by a gap, which is thought to have been carved by newly forming gas giant planets clearing out their orbits as they circle the star. The inner disc reaches from the star out to the equivalent of the orbit of Saturn in the Solar System, while the outer disc begins about 14 times further out. The outer disc does not surround the star uniformly; instead, it has a horseshoe shape, probably caused by the gravitational effect of the orbiting giant planets.

According to theory, the giant planets grow by capturing gas from the outer disc, in streams that form bridges across the gap in the disc.
The observations answer another question about the disc around HD 142527. As the central star is still forming, by capturing material from the inner disc, the inner disc would have already been devoured, if it was not somehow topped up. The team found that the rate at which leftover gas streams onto the inner disc is just right to keep the inner disc replenished, and to feed the growing star.

Aveti mai jos si alte link-uri

http://www.eso.org/public/news/eso1301/

http://astronomy.com/news/2013/01/alma-sheds-light-on-planet-forming-gas-streams

 

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