I pianeti si formano in dischi di gas e polveri che circondano le giovani stelle. Gli astronomi sono stati in grado di ottenere, per la prima volta, immagini dettagliate di tali dischi protoplanetari attorno a due stelle, grazie al telescopio Subaru delle Hawaii. Le immagini rivelano con chiarezza caratteristiche come gli anelli e le lacune presenti che sono associate con la formazione di pianeti giganti.
Le osservazioni fanno parte di una indagine sistematica per la ricerca di pianeti attorno a stelle con dischi di formazione planetaria, condotta grazie ad una telecamera ad elevato contrasto progettata specificamente per questo scopo.
I sistemi planetari come il nostro formed by the force of gravity which collects the gas and dust made by the advanced star formation in a dense, flattened disk of material orbiting the star. The same force of gravity of the denser material around nuclei to form heavier compression of dense bodies, called planets. Recent years have seen substantial progress in both observations (mostly indirect) and in the development of theoretical models on the disks "protoplanetary". The two intriguing new observations have added new details to reveal some structures that had never been seen directly.
The first of the two stars is observed LkCa 15, which is located about 450 light years from Earth in the constellation Taurus. With a few million years of age, LkCa 15 is a young star from the Sun is a thousand times older. From previous observations of its infrared spectrum and analysis of its emissions, scientists have inferred the presence of a large gap in the center of its protoplanetary disk. The new images show the starlight shining off the disk surface, which outline clearly for the first time the cutting edge. Even more interesting is the elliptical shape of the gap that is not centered on the star, but it is lopsided.
"The most likely explanation for the gap LkCa disk 15 and in particular its asymmetry, is that one or more planets, newborn from the material of the disc, have swept away the gas and dust along their orbits, "says Christian Thalmann, who led the study at the Max Planck Institute for Astronomy (MPIA). Interestingly, the gap in the disk is large enough to accommodate all the orbits of the planets in our Solar System. LkCa It is assumed therefore that 15 might be about to form a whole planetary system similar to ours. "We have not yet found the same kinds of planets," said Thalmann, "but this may change soon."
The second observation stellar, led by Jun Hashimoto (National Observatory of Japan), focused on AB Aur in constellation, at a distance of 470 light years from Earth. This star is even younger, with an age of only one million years. Even the earliest observations showed length scales comparable to the size of our solar system, with a ring of material inclined with respect to the equatorial plane of the disk, curiously, is not distributed symmetrically around the star, with irregular features that indicate the presence of at least one planet very solid.
The observations made with the instrument HiCIAO installed on the 8.2-meter Subaru Telescope corrects distortion of Earth's atmosphere and physically block most of the light from the star, allowing you to see which ones that exist around it.
The observations are part of SEEDS project, an acronym for Strategic Explorations of Exoplanets and Disks with Subaru.
Photo above: L 'image above, taken with the camera installed on HiCIAO Subaru Telescope shows a bright arc of diffuse light (white) from the protoplanetary disk around the young star LkCa 15 ( the center, masked with a dark circle). E ' an arc cutting the edge of the internal shape with a large gap in the disk. The gap is very unbalanced and is much wider on the left side, and was probably dug by one or more planets orbiting the star babies. (Credit: Copyright MPIA (Christian Thalmann) & NAOJ) .
Translation by Arthur McPaul
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