The analysis of thirty iced racing cars in the orbit of this nearby star, 63-light years from us, sheds light on the process of forming planetary systems.
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For several decades, the Beta Pictoris star – which, as its name Greco -Latin indicates, belongs to the southern constellation of the painter – is regularly found in the fires of scientific news. This is still the case with the publication, Thursday April 28, in Scientific Reports, of an international study led by a French team , which describes a sample of no less than 30 comets observed around this star located only 63 light years from us. A modest distance if we compare it to the 100,000 light years that should be traversed to go from one end to the other of our galaxy, the Milky Way.
If Beta Pictoris is one of the “darling” of astronomers, she owes it only to her proximity. Two other properties make it exceptional in their eyes, explains Alain Lecavelier des Etangs, CNRS research director at the Institut d’Astrophysiques de Paris (IAP) and first author of this new study: “It is a young star – 20 million years – which comes out of maternity with a very active planetary system: we know two planets, many small bodies and it especially has a disc of debris produced by collisions. Last asset, we see this disc By the edge, which means that, from our point of view, all the objects in orbit around the star pass in front of it. “
an improbable configuration
Proximity, tumultuous youth, good angle of view, each of these factors taken separately is not great in itself, “but the three together, it is completely improbable”, continues the researcher of the IAP. “If we had bet, no one would have bet on the existence of such an object. It is a real laboratory that allows us to do a lot of studies on what is happening in the final phase of the formation of a planetary system. “
This phase is the scene of a real cometary whirlwind. The discovery of comets around Beta Pictoris is not new, because we have known it since the 1980s. “We then detected them by spectroscopy, recalls Alain Lecavelier of the Etangs. We observed certain rays of the light spectrum of the star be temporarily absorbed, which indicated that a gas cloud appeared and then disappeared. “This fugitive appearance betrayed the passage of comets. As we regularly see by us, as the sun approaches, these large ice cream balls and dust degrees in space, which gives them well characteristic hair and tails.
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