Probing discs around massive young stellar objects with CO first overtone emission

作者：Wheelwright H E^*; Oudmaijer R D; de Wit W J; Hoare M G; Lumsden S L; Urquhart J S

来源：Monthly Notices of the Royal Astronomical Society, 2010, 408(3): 1840-1850.

DOI：10.1111/j.1365-2966.2010.17250.x

• accretion
• accretion discs
• line: profiles
• techniques: high angular resolution
• circumstellar matter
• stars: formation
• stars: massive

We present high-resolution (R similar to 50 000) spectroastrometry over the CO first overtone bandhead of a sample of seven intermediate/massive young stellar objects. These are primarily drawn from the Red MSX source (RMS) survey, a systematic search for young massive stars which has returned a large, well selected sample of such objects. The mean luminosity of the sample is approximately 5 x 104 L(circle dot), indicating the objects typically have a mass of similar to 15 M(circle dot). We fit the observed bandhead profiles with a model of a circumstellar disc, and find good agreement between the models and observations for all but one object. We compare the high angular precision (0.2-0.8 x 10-3 arcsec) spectroastrometric data to the spatial distribution of the emitting material in the best-fitting models. No spatial signatures of discs are detected, which is entirely consistent with the properties of the best-fitting models. Therefore, the observations suggest that the CO bandhead emission of massive young stellar objects originates in small-scale discs, in agreement with previous work. This provides further evidence that massive stars form via disc accretion, as suggested by recent simulations.

• 出版日期2010-11-1
• 单位CSIRO