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A gap in HD 92945’s broad planetesimal disc revealed by ALMA
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Marino, S., Yelverton, B., Booth, M., Faramaz, V., Kennedy, Grant M., Matrà, L. and Wyatt, M. C. (2019) A gap in HD 92945’s broad planetesimal disc revealed by ALMA. Monthly Notices of the Royal Astronomical Society, 484 (1). pp. 1257-1269. doi:10.1093/mnras/stz049 ISSN 1745-3933.
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Official URL: http://dx.doi.org/10.1093/mnras/stz049
Abstract
In the last few years, multiwavelength observations have revealed the ubiquity of gaps/rings in circumstellar discs. Here we report the first ALMA observations of HD 92945 at 0.86 mm, which reveal a gap at about 73 ± 3 au within a broad disc of planetesimals that extends from 50 to 140 au. We find that the gap is 20^{+10}_{-8} au wide. If cleared by a planet in situ, this planet must be less massive than 0.6 MJup, or even lower if the gap was cleared by a planet that formed early in the protoplanetary disc and prevented planetesimal formation at that radius. By comparing opposite sides of the disc, we also find that the disc could be asymmetric. Motivated by the asymmetry and the fact that planets might be more frequent closer to the star in exoplanetary systems, we show that the gap and asymmetry could be produced by two planets interior to the disc through secular resonances. These planets excite the eccentricity of bodies at specific disc locations, opening radial gaps in the planetesimal distribution. New observations are necessary to confirm if the disc is truly asymmetric, thus favouring the secular resonance model, or if the apparent asymmetry is due to a background galaxy, favouring the in situ planet scenario. Finally, we also report the non-detection of CO and HCN gas, confirming that no primordial gas is present. The CO and HCN non-detections are consistent with the destruction of volatile-rich Solar system-like comets.
Item Type: | Journal Article | |||||||||||||||
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Subjects: | Q Science > QD Chemistry | |||||||||||||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | |||||||||||||||
Library of Congress Subject Headings (LCSH): | Circumstellar matter, Planetary systems | |||||||||||||||
Journal or Publication Title: | Monthly Notices of the Royal Astronomical Society | |||||||||||||||
Publisher: | Oxford University Press | |||||||||||||||
ISSN: | 1745-3933 | |||||||||||||||
Official Date: | 21 March 2019 | |||||||||||||||
Dates: |
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Volume: | 484 | |||||||||||||||
Number: | 1 | |||||||||||||||
Page Range: | pp. 1257-1269 | |||||||||||||||
DOI: | 10.1093/mnras/stz049 | |||||||||||||||
Status: | Peer Reviewed | |||||||||||||||
Publication Status: | Published | |||||||||||||||
Reuse Statement (publisher, data, author rights): | This is a pre-copyedited, author-produced version of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record S Marino, B Yelverton, M Booth, V Faramaz, G M Kennedy, L Matrà, M C Wyatt; A gap in HD 92945’s broad planetesimal disc revealed by ALMA, Monthly Notices of the Royal Astronomical Society, Volume 484, Issue 1, 21 March 2019, Pages 1257–1269, https://doi.org/10.1093/mnras/stz049 is available online at: https://doi.org/10.1093/mnras/stz049 | |||||||||||||||
Access rights to Published version: | Restricted or Subscription Access | |||||||||||||||
Date of first compliant deposit: | 4 February 2019 | |||||||||||||||
Date of first compliant Open Access: | 4 February 2019 | |||||||||||||||
RIOXX Funder/Project Grant: |
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Open Access Version: |
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