ALMA Resolves C i Emission from the β Pictoris Debris Disk
Journal article, 2018
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 ×10-4and 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 MMoon.
stars: individual (beta Pictoris)
radiative transfer
techniques: interferometric
methods: observational
circumstellar matter
submillimeter: planetary systems
Author
Gianni Cataldi
Hungarian Academy of Sciences
National Astronomical Observatory of Japan
Stockholm University
AlbaNova University Center
A. Brandeker
AlbaNova University Center
Stockholm University
Y. Wu
University of Toronto
C. H. Chen
Space Telescope Science Institute (STScI)
Johns Hopkins University
W. R. F. Dent
European Southern Observatory Santiago
B. L. D. Vries
AlbaNova University Center
European Space Research and Technology Centre (ESA ESTEC)
Stockholm University
I. Kamp
University of Groningen
René Liseau
Chalmers, Space, Earth and Environment, Onsala Space Observatory
G. Olofsson
AlbaNova University Center
Stockholm University
E. Pantin
Centre national de la recherche scientifique (CNRS)
A. Roberge
National Aeronautics and Space Administration (NASA)
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 861 1 72Subject Categories (SSIF 2011)
Subatomic Physics
Astronomy, Astrophysics and Cosmology
DOI
10.3847/1538-4357/aac5f3