Open AccessNear‐infrared line spectropolarimetry of hot massive stars
Author(s) -
Oudmaijer René D.,
Drew Janet E.,
Vink Jorick S.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09598.x
Subject(s) - physics , astrophysics , position angle , t tauri star , young stellar object , polarization (electrochemistry) , stars , astronomy , wavelength , infrared , flattening , circumstellar dust , herbig ae/be star , star formation , optics , k type main sequence star , galaxy , chemistry
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 Paβ 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 ζ Tau, known to display line polarization changes at optical wavelengths, was observed as well. Three of our targets show a ‘line effect’ across Paβ. For ζ Tau and MWC 349A, this line effect is due to depolarization by a circumstellar electron‐scattering disc. In both cases, the position angle of the polarization is consistent with that of the larger scale discs 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 Paβ in the embedded massive young stellar object GL 490 suggests the presence of a small‐scale rotating accretion disc with an inner hole – similar to those recently discovered at optical wavelengths in Herbig Ae and T Tauri stars.