La croissance de grains de poussière cosmique dans le disque autour de la naine brune ISO-Oph 102
Les planètes rocheuses sont supposées se former lors des collisions aléatoires provoquant l'agglomération de ce qui était à l'origine des particules microscopiques dans le disque de matière entourant les étoiles. Ces minuscules grains, connus sous le non de poussière cosmique, ressemblent à de la suie très fine ou à du sable. Des astronomes observant avec le grand réseau d'antennes millimétrique / submillimétrique ALMA (Atacama Large Millimeter/submillimeter Array) ont découvert pour la première fois à la périphérie d'un disque de poussière encerclant une naine brune - un objet semblable à une étoile, mais trop petit pour briller comme une étoile - la présence de grains de poussière de la taille du millimètre comme ceux que l'on trouve dans les disques denses qui entourent les étoiles qui viennent de naître. Cette surprenante découverte défie les théories décrivant comment les planètes rocheuses de la taille de la Terre se forment et laisse supposer que les planètes telluriques doivent être bien plus communes dans l'Univers que ce nous ne pouvions l'imaginer.
Cette vidéo commence par un vaste panorama des spectaculaires régions centrales de la Voie Lactée en lumière visible. Nous zoomons ensuite dans la région de formation d'étoiles Rho Ophiuchi, vers la naine brune ISO-Oph 102, également appelée Rho-Oph 102. Puis, une vue d'artiste montre le disque de matière autour de la naine brune et zoome afin de montrer comment les petits grains s'entrechoquent et se collent les uns aux autres pour former de plus gros grains.
Crédit:ALMA (ESO/NAOJ/NRAO)/L. Calçada (ESO)/M. Kornmesser (ESO)/Nick Risinger (skysurvey.org)/Digitized Sky Survey 2 Music: movetwo
À propos de la vidéo
| Identification: | eso1248a |
| Langage: | fr |
| Date de publication: | 30 novembre 2012 12:00 |
| Communiqués de presse en rapport: | eso1248 |
| Durée: | 01 m 18 s |
| Frame rate: | 30 fps |
À propos de l'objet
| Nom: | ISO-Oph 102 |
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