High-precision Dynamical Masses of Pre-main-sequence Stars with ALMA and Gaia

Patrick D. Sheehan, Ya Lin Wu, Josh A. Eisner, John J. Tobin

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


The Keplerian rotation in protoplanetary disks can be used to robustly measure stellar masses at very high precision if the source distance is known. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of spatially and spectrally resolved 12 CO (2-1) emission toward the disks around 2MASS J16262774-2527247 (the tertiary companion to ROXs 12 at 5100 au), CT Cha, and DH Tau. We employ detailed modeling of the Keplerian rotation profile, coupled with accurate distances from Gaia, to directly measure the stellar masses with ∼2% precision. We also compare these direct mass measurements with the masses inferred from evolutionary models, determined in a statistically rigorous way. We find that 2MASS J16262774-2527247 has a mass of and CT Cha has a mass of , broadly consistent with evolutionary models, although potentially significant differences remain. DH Tau has a mass of , but it suffers from strong foreground absorption that may affect our mass estimate. The combination of ALMA, Gaia, and codes like pdspy, presented here, can be used to infer the dynamical masses for large samples of young stars and substellar objects, and place constraints on evolutionary models.

Original languageEnglish
Article number136
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 2019 Apr 1
Externally publishedYes


  • parallaxes
  • protoplanetary disks
  • radio lines: stars
  • stars: fundamental parameters
  • stars: pre-main sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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