Herschel detects oxygen in the ? Pictoris debris disk
Artikel i vetenskaplig tidskrift, 2016
The young star β Pictoris is well known for its dusty debris disk produced through collisional grinding of planetesimals, kilometre-sized bodies in orbit around the star. In addition to dust, small amounts of gas are also known to orbit the star; this gas is likely the result of vaporisation of violently colliding dust grains. The disk is seen edge on and from previous absorption spectroscopy we know that the gas is very rich in carbon relative to other elements. The oxygen content has been more difficult to assess, however, with early estimates finding very little oxygen in the gas at a C/O ratio that is 20× higher than the cosmic value. A C/O ratio that high is difficult to explain and would have far-reaching consequences for planet formation. Here we report on observations by the far-infrared space telescope Herschel, using PACS, of emission lines from ionised carbon and neutral oxygen. The detected emission from C+ is consistent withthat previously reported observed by the HIFI instrument on Herschel, while the emission from O is hard to explain without assuming a higher density region in the disk, perhaps in the shape of a clump or a dense torus required to sufficiently excite the O atoms. A possible scenario is that the C/O gas is produced by the same process responsible for the CO clump recently observed by the Atacama Large Millimeter/submillimeter Array in the disk and that the redistribution of the gas takes longer than previously assumed. A more detailed estimate of the C/O ratio and the mass of O will have to await better constraints on the C/O gas spatial distribution.
Stars: individual: beta Pictoris
Stars: early-type
Circumstellar matter
Författare
A. Brandeker
Stockholms universitet
G. Cataldi
Stockholms universitet
G. Olofsson
Stockholms universitet
B. Vandenbussche
KU Leuven
B. Acke
KU Leuven
M. J. Barlow
University College London (UCL)
Jadl Blommaert
Vrije Universiteit Brüssel (VUB)
KU Leuven
M. Cohen
University of California
W. R. F. Dent
Atacama Large Millimeter-submillimeter Array (ALMA)
C. Dominik
Radboud Universiteit
Anton Pannekoek Institute for Astronomy
J. Di Francesco
National Research Council Canada
Malcolm Fridlund
Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik
W. K. Gear
Cardiff University
A. M. Glauser
Royal Observatory
Eidgenössische Technische Hochschule Zürich (ETH)
J. S. Greaves
University of St Andrews
P. M. Harvey
University of Texas
A. Heras
Europeiska rymdorganisationen (ESA)
M. R. Hogerheijde
Universiteit Leiden
W. S. Holland
Royal Observatory
R. Huygen
KU Leuven
R. J. Ivison
European Southern Observatory (ESO)
University of Edinburgh
S. J. Leeks
STFC Rutherford Appleton Laboratory
T. L. Lim
STFC Rutherford Appleton Laboratory
René Liseau
Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik
B. C. Matthews
National Research Council Canada
E. Pantin
Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)
G.L. Pilbratt
Europeiska rymdorganisationen (ESA)
P. Royer
KU Leuven
B. Sibthorpe
Netherlands Institute for Space Research (SRON)
C. Waelkens
KU Leuven
H. Walker
STFC Rutherford Appleton Laboratory
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 591 Art. no. A27- A27Ämneskategorier (SSIF 2011)
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/201628395