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

Circumstellar matter

Stars: early-type


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

KU Leuven

Vrije Universiteit Brüssel (VUB)

M. Cohen

University of California

W. R. F. Dent

Atacama Large Millimeter-submillimeter Array (ALMA)

C. Dominik

Anton Pannekoek Institute for Astronomy

Radboud Universiteit

J. Di Francesco

National Research Council Canada

Malcolm Fridlund

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

W. K. Gear

Cardiff University

A. M. Glauser

Eidgenössische Technische Hochschule Zürich (ETH)

Royal Observatory

J. S. Greaves

University of St Andrews

P. M. Harvey

The University of Texas at Austin

A. Heras

European Space Research and Technology Centre (ESA ESTEC)

M. R. Hogerheijde

Universiteit Leiden

W. S. Holland

Royal Observatory

R. Huygen

KU Leuven

R. J. Ivison

University of Edinburgh

European Southern Observatory (ESO)

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

European Space Research and Technology Centre (ESA ESTEC)

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- A27


Astronomi, astrofysik och kosmologi



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