Herschel detects oxygen in the ? Pictoris debris disk
Journal article, 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


A. Brandeker

Stockholm University

G. Cataldi

Stockholm University

G. Olofsson

Stockholm University

B. Vandenbussche

KU Leuven

B. Acke

KU Leuven

M. J. Barlow

University College London (UCL)

Jadl Blommaert

KU Leuven

Vrije Universiteit Brussel (VUB)

M. Cohen

University of California

W. R. F. Dent

Atacama Large Millimeter-submillimeter Array (ALMA)

C. Dominik

Radboud University

Anton Pannekoek Institute for Astronomy

J. Di Francesco

National Research Council Canada

Malcolm Fridlund

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

W. K. Gear

Cardiff University

A. M. Glauser

Swiss Federal Institute of Technology in 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

Leiden University

W. S. Holland

Royal Observatory

R. Huygen

KU Leuven

R. J. Ivison

European Southern Observatory (ESO)

University of Edinburgh

S. J. Leeks

Rutherford Appleton Laboratory

T. L. Lim

Rutherford Appleton Laboratory

René Liseau

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

B. C. Matthews

National Research Council Canada

E. Pantin

The French Alternative Energies and Atomic Energy Commission (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

Rutherford Appleton Laboratory

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 591 Art. no. A27- A27

Subject Categories

Astronomy, Astrophysics and Cosmology



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