Near-infrared line spectropolarimetry of hot massive stars
In order to study the inner parts of the circumstellar material around optically faint, infrared bright objects, we present the first medium-resolution spectropolarimetric data taken in the near-infrared. In this paper we discuss Pa line data of GL 490, a well-known embedded massive young stellar object, and of MWC 349A and MWC 342, two optically faint stars that are proposed to be in the pre-main sequence phase of evolution. As a check on the method, the classical Be star Tau, known to display line polarization changes at optical wavelengths, was observed as well. Three of our targets show a “line effect” across Pa . For Tau and MWC 349A this line effect is due to depolarisation by a circumstellar electron-scattering disk. In both cases, the position angle of the polarisation is consistent with that of the larger scale disks imaged at other wavelengths, validating infrared spectropolarimetry as a means to detect flattening on small scales. The tentative detection of a rotation in the polarization position angle at Pa in the embedded massive young stellar object GL 490 suggests the presence of a small scale rotating accretion disk with an inner hole – similar to those recently discovered at optical wavelengths in Herbig Ae and T Tauri stars.
Item Type | Article |
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Additional information | The definitive version is available at www.blackwell-synergy.com. Copyright Blackwell Publishing --DOI : 10.1111/j.1365-2966.2005.09598.x |
Date Deposited | 15 May 2025 11:50 |
Last Modified | 30 May 2025 23:38 |
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