ALMA OBSERVATIONS of the LARGEST PROTO-PLANETARY DISK in the ORION NEBULA, 114-426: A CO SILHOUETTE

John Bally, Rita K. Mann, Josh Eisner, Sean M. Andrews, James Di Francesco, Meredith Hughes, Doug Johnstone, Brenda Matthews, Luca Ricci, Jonathan P. Williams

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

We present ALMA observations of the largest protoplanetary disk in the Orion Nebula, 114-426. Detectable 345 GHz (856 μm) dust continuum is produced only in the 350 AU central region of the ∼1000 AU diameter silhouette seen against the bright background in Hubble Space Telescope images. Assuming optically thin dust emission at 345 GHz, a gas-to-dust ratio of 100, and a grain temperature of 20 K, the disk gas-mass is estimated to be Jupiter masses. If most solids and ices have been incorporated into large grains, however, this value is a lower limit. The disk is not detected in dense-gas tracers such as HCO+ J = 4-3, HCN J = 4-3, or CS = 7-6. These results may indicate that the 114-426 disk is evolved and depleted in some light organic compounds found in molecular clouds. The CO J = 3-2 line is seen in absorption against the bright 50-80 K background of the Orion A molecular cloud over the full spatial extent and a little beyond the dust continuum emission. The CO absorption reaches a depth of 27 K below the background CO emission at VLSR 6.7 km s ∼ 0.″52 (210 AU) northeast and 12 K below the background CO emission at VLSR ≈ 9.7 km s ∼ 0.″34 (140 AU) southwest of the suspected location of the central star, implying that the embedded star has a mass less than 1 M.·

Original languageEnglish (US)
Article number69
JournalAstrophysical Journal
Volume808
Issue number1
DOIs
StatePublished - Jul 20 2015

Keywords

  • circumstellar matter
  • protoplanetary disks
  • stars: pre-main sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Bally, J., Mann, R. K., Eisner, J., Andrews, S. M., Francesco, J. D., Hughes, M., Johnstone, D., Matthews, B., Ricci, L., & Williams, J. P. (2015). ALMA OBSERVATIONS of the LARGEST PROTO-PLANETARY DISK in the ORION NEBULA, 114-426: A CO SILHOUETTE. Astrophysical Journal, 808(1), [69]. https://doi.org/10.1088/0004-637X/808/1/69