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Mass constraints for 15 protoplanetary discs from HD 1-0

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Kama, M 
Trapman, L 
Fedele, D 
Bruderer, S 
Hogerheijde, MR 


jats:pjats:italicContext.</jats:italic> Hydrogen deuteride (HD) rotational line emission can provide reliable protoplanetary disc gas mass measurements, but this molecule is difficult to observe and detections have been limited to three T Tauri discs. No new data have been available since the jats:italicHerschel</jats:italic> Space Observatory mission ended in 2013.</jats:p> jats:pjats:italicAims.</jats:italic> We set out to obtain new disc gas mass constraints by analysing upper limits on HD 1–0 emission in jats:italicHerschel</jats:italic>/PACS archival data from the DIGIT key programme.</jats:p> jats:pjats:italicMethods.</jats:italic> With a focus on the Herbig Ae/Be discs, whose stars are more luminous than T Tauris, we determined upper limits for HD in data previously analysed for its line detections. We studied the significance of these limits with a grid of models run with the DALI physical-chemical code, customised to include deuterium chemistry.</jats:p> jats:pjats:italicResults.</jats:italic> Nearly all the discs are constrained to jats:italicM</jats:italic>jats:subgas</jats:sub> ≤ 0.1 jats:italicM</jats:italic>jats:sub⊙</jats:sub>, ruling out global gravitational instability. A strong constraint is obtained for the HD 163296 disc mass, jats:italicM</jats:italic>jats:subgas</jats:sub> ≤ 0.067 jats:italicM</jats:italic>jats:sub⊙</jats:sub>, implying Δjats:subg/d</jats:sub> ≤ 100. This HD-based mass limit is towards the low end of CO-based mass estimates for the disc, highlighting the large uncertainty in using only CO and suggesting that gas-phase CO depletion in HD 163296 is at most a factor of a few. The jats:italicM</jats:italic>jats:subgas</jats:sub> limits for HD 163296 and HD 100546, both bright discs with massive candidate protoplanetary systems, suggest disc-to-planet mass conversion efficiencies of jats:italicM</jats:italic>jats:subp</jats:sub>/(jats:italicM</jats:italic>jats:subgas</jats:sub> + jats:italicM</jats:italic>jats:subp</jats:sub>) ≈ 10–40% for present-day values. Near-future observations with SOFIA/HIRMES will be able to detect HD in the brightest Herbig Ae/Be discs within 150 pc with ≈ 10 h integration time.</jats:p>



planets and satellites, formation, protoplanetary discs, circumstellar matter, planets and satellites, gaseous planets

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Astronomy and Astrophysics

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EDP Sciences


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European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (823823)
European Research Council (341137)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (753799)
Science and Technology Facilities Council (ST/N000927/1)
Science and Technology Facilities Council (ST/S000623/1)