Spectral line profiles changed by dust scattering in heavily obscured young stellar objects

¹ Pulkovo Astronomical Observatory of the Russian Academy of Sciences, Pulkovskoe shosse 65, 196140 St. Petersburg, Russia
e-mail: grinin@gao.spb.ru; lvtamb@mail.ru
² The V.V. Sobolev Astronomical Institute of the St. Petersburg University, Petrodvorets, 198904 St. Petersburg, Russia
³ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
e-mail: weigelt@mpifr-bonn.mpg.de

Received: 6 June 2012
Accepted: 2 July 2012

Abstract

It is known that scattering of radiation by circumstellar dust can strongly change the line profiles in stellar spectra. This hampers the analysis of spectral lines originating in the emitting regions of heavily obscured young stars. To calculate the line profile of the scattered radiation, we suggest to use the approximation of remote scattering particles. This approximation assumes that the scattering dust grains are at a distance from the star that is much larger than the characteristic size of the emitting region. Using this method, we calculated the line profiles of several simple models. They show the Hα line profiles of Herbig AeBe stars in the presence and absence of motionless or moving dust.