Year: 2018
Type: article
Abstract: The debris disk around β Pictoris is known to contain gas. Previous ALMA observations revealed a CO belt at ∼85 au with a distinct clump, interpreted as a location of enhanced gas production. Photodissociation converts CO into C and O within ∼50 a. We resolve C i emission at 492 GHz using ALMA and study its spatial distribution. C i shows the same clump as seen for CO. This is surprising, as C is expected to quickly spread in azimuth. We derive a low C mass (between 5 × 10−4 and 3.1 × 10−3 ), indicating that gas production started only recently (within ∼5000 a). No evidence is seen for an atomic accretion disk inward of the CO belt, perhaps because the gas did not yet have time to spread radially. The fact that C and CO share the same asymmetry argues against a previously proposed scenario where the clump is due to an outward-migrating planet trapping planetesimals in a resonance, nor can the observations be explained by an eccentric planetesimal belt secularly forced by a planet. Instead, we suggest that the dust and gas disks should be eccentric. Such a configuration, we further speculate, might be produced by a recent tidal disruption event. Assuming that the disrupted body has had a CO mass fraction of 10%, its total mass would be ≳3 M Moon.
Source: The Astrophysical Journal
Authors: Gianni Cataldi, Alexis Brandeker, Yanqin Wu, Christine Chen, William Dent, Bernard L. de Vries, Inga Kamp, René Liseau, Göran Olofsson, Eric Pantin, Aki Roberge
Institutions: Stockholm University, Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, AlbaNova, National Astronomical Observatory of Japan, Hungarian Academy of Sciences, University of Toronto, Space Telescope Science Institute, Johns Hopkins University, Atacama Large Millimeter Submillimeter Array, European Space Research and Technology Centre, University of Groningen, Chalmers University of Technology, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Astrophysique, Instrumentation et Modélisation, Université Paris Diderot, Goddard Space Flight Center
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Award: 惑星系形成の理解へ向けて―星周円盤の研究
OpenAlex ID: W2797405913