Year: 2014
Type: article
Abstract: HD 50138 is a B[e] star surrounded by a large amount of circumstellar gas and dust. Its spectrum shows characteristics which may indicate either a pre- or a post-main-sequence system. Mapping the kinematics of the gas in the inner few au of the system contributes to a better understanding of its physical nature. We present the first high spatial and spectral resolution interferometric observations of the Brγ line of HD 50138, obtained with VLTI/AMBER. The line emission originates in a region more compact (up to 3 au) than the continuum-emitting region. Blue- and red-shifted emission originates from the two different hemispheres of an elongated structure perpendicular to the polarization angle. The velocity of the emitting medium decreases radially. An overall offset along the NW direction between the line- and continuum-emitting regions is observed. We compare the data with a geometric model of a thin Keplerian disk and a spherical halo on top of a Gaussian continuum. Most of the data are well reproduced by this model, except for the variability, the global offset and the visibility at the systemic velocity. The evolutionary state of the system is discussed; most diagnostics are ambiguous and may point either to a post-main-sequence or a pre-main-sequence nature.
Source: Astronomy and Astrophysics
Authors: L. E. Ellerbroek, M. Benisty, S. Kraus, K. Perraut, J. Kluska, J. B. le Bouquin, M. Borges Fernandes, A. Domiciano de Souza, K. M. Maaskant, L. Kaper, F. Tramper, D. Mourard, I. Tallon-Bosc, T. ten Brummelaar, M. L. Sitko, D. K. Lynch, R. W. Russell
Institutions: University of Amsterdam, Centre National de la Recherche Scientifique, Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes, University of Exeter, National Observatory, Lagrange Laboratory, Observatoire de la Côte d’Azur, Leiden University, Leiden Observatory, Lyon 1 Université, École Normale Supérieure de Lyon, Université de Lyon, Observatoire de Lyon, Centre de Recherche Astrophysique de Lyon, Georgia State University, Mount Wilson Observatory, Space Science Institute, University of Cincinnati, The Aerospace Corporation
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2060508703