G11.92-0.61 MM 1 : a fragmented Keplerian disk surrounding a proto-O star
Abstract
We present high-resolution (~300 au) Atacama Large Millimeter/submillimeter Array observations of the massive young stellar object G11.92–0.61 MM 1. We resolve the immediate circumstellar environment of MM 1 in 1.3 mm continuum emission and CH3CN emission for the first time. The object divides into two main sources—MM 1a, which is the source of a bipolar molecular outflow, and MM 1b, located 0."57 (1920 au) to the southeast. The main component of MM 1a is an elongated continuum structure, perpendicular to the bipolar outflow, with a size of 0."141 × 0."050 (480 × 170 au). The gas kinematics toward MM 1a probed via CH3CN trace a variety of scales. The lower energy J = 12–11 K = 3 line traces extended, rotating gas within the outflow cavity, while the v8 = 1 line shows a clearly resolved Keplerian rotation signature. Analysis of the gas kinematics and dust emission shows that the total enclosed mass in MM 1a is 40 ± 5 M ⊙ (where between 2.2 and 5.8 M ⊙ is attributed to the disk), while MM 1b is <0.6 M ⊙. The extreme mass ratio and orbital properties of MM 1a and MM 1b suggest that MM 1b is one of the first observed examples of the formation of a binary star via disk fragmentation around a massive young (proto)star.
Citation
Ilee , J D , Cyganowski , C J , Brogan , C L , Hunter , T R , Forgan , D H , Haworth , T J , Clarke , C J & Harries , T J 2018 , ' G11.92-0.61 MM 1 : a fragmented Keplerian disk surrounding a proto-O star ' , Astrophysical Journal Letters , vol. 869 , no. 2 , L24 . https://doi.org/10.3847/2041-8213/aaeffc
Publication
Astrophysical Journal Letters
Status
Peer reviewed
ISSN
2041-8205Type
Journal article
Description
J.D.I. is funded by the STFC (ST/R000549/1), and J.D.I. and C.J. Clarke are funded by the DISCSIM project, grant agreement 341137 (ERC-2013-ADG). C.J. Cyganowski is funded by the STFC (ST/M001296/1). D.H.F. is funded by the ECOGAL project, grant agreement 291227 (ERC-2011-ADG). T.J. Haworth is funded by an Imperial College Junior Research Fellowship. T.J. Harries is funded by the STFC (ST/M00127X/1).Collections
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