The evolution of circumstellar discs in the galactic centre: an application to the G-clouds
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Published version
Author(s)
Owen, James E
Lin, Douglas NC
Type
Journal Article
Abstract
The Galactic Centre is known to have undergone a recent star formation episode a few Myr ago, which likely produced many T Tauri stars hosting circumstellar discs. It has been suggested that these discs may be the compact and dusty ionized sources identified as ‘G-clouds’. Given the Galactic Centre’s hostile environment, we study the possible evolutionary pathways these discs experience. We compute new external photoevaporation models applicable to discs in the Galactic Centre that account for the subsonic launching of the wind and absorption of UV photons by dust. Using evolutionary disc calculations, we find that photoevaporation’s rapid truncation of the disc causes them to accrete onto the central star rapidly. Ultimately, an accreting circumstellar disc has a lifetime ≲ 1 Myr, which would fail to live long enough to explain the G-clouds. However, we identify a new evolutionary pathway for circumstellar discs in the Galactic Centre. Removal of disc material by photoevaporation prevents the young star from spinning down due to magnetic braking, ultimately causing the rapidly spinning young star to torque the disc into a ‘decretion disc’ state which prevents accretion. At the same time, any planetary companion in the disc will trap dust outside its orbit, shutting down photoevaporation. The disc can survive for up to ∼10 Myr in this state. Encounters with other stars are likely to remove the planet on Myr time-scales, causing photoevaporation to restart, giving rise to a G-cloud signature. A giant planet fraction of ∼10 per cent
can explain the number of observed G-clouds.
can explain the number of observed G-clouds.
Date Issued
2023-02
Date Acceptance
2022-11-26
Citation
Monthly Notices of the Royal Astronomical Society, 2023, 519 (1), pp.397-417
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
397
End Page
417
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
519
Issue
1
Copyright Statement
© The Author(s) 2022.
Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.
Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.
License URL
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000913852500012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Subjects
accretion
accretion discs
Astronomy & Astrophysics
black hole physics
CENTRAL PARSEC
EXTERNAL PHOTOEVAPORATION
galaxy:centre
MAGNETIC NEUTRON-STARS
MASS-DISTRIBUTION
Physical Sciences
PROPELLER REGIME
protoplanetary discs
PROTOSTELLAR DISKS
Science & Technology
SGR A-ASTERISK
SPECTRAL ENERGY-DISTRIBUTIONS
stars-pre-main-sequence
SUPERMASSIVE BLACK-HOLE
YOUNG STARS
Publication Status
Published
Date Publish Online
2022-12-01