The galactic unclassified B[e] star HD 50138 - I. A possible new shell phase

  title={The galactic unclassified B[e] star HD 50138 - I. A possible new shell phase},
  author={M. Fernandes and M. Kraus and O. Chesneau and A. D. D. Souza and F. X. Ara{\'u}jo and P. Stee and Anthony Meilland Fizeau and France. and A. Ondrejov and Czech Repubic and O. Nacional and Brazil. and Mpifr and H Germany},
  journal={Astronomy and Astrophysics},
Context. The observed spectral variation of HD 50138 has led different authors to classify it in a very wide range of spectral types and luminosity classes (from B5 to A0 and III to Ia) and at different evolutionary stages as either HAeBe star or classical Be. Aims. Based on new high-resolution optical spectroscopic data from 1999 and 2007 associated to a photometric analysis, the aim of this work is to provide a deep spectroscopic description and a new set of parameters for this unclassified… Expand
The Galactic unclassified B[e] star HD 50138 - III. The short-term line profile variability of its photospheric lines
Context. HD 50138 presents the B[e] phenomenon, but its nature is not clear yet. This star is known to present spectral variations, which have been associated with outbursts and shell phases. Aims.Expand
The galactic unclassified B(e) star HD 50138 ??? II. Interferometric constraints on the close circumstellar environment
Context. HD 50138 is a southern star that presents the B[e] phenomenon, but its evolutionary stage is still not well known. This object presents spectral variability, which can be explained byExpand
Dust evolution in the circumstellar disc of the unclassified B[e] star HD 50138
We studied the disc of the unclassified B[e] star HD 50138, in order to explore its structure, and to find indications for the evolutionary status of this system, whether it is a young Herbig Be or aExpand
A resolved, au-scale gas disk around the B[e] star HD 50138
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 theExpand
The circumstellar environment of HD50138 revealed by VLTI/AMBER at high angular resolution
HD50138 is a Herbig B[e] star with a circumstellar disc detected at IR and mm wavelength. Its brightness makes it a good candidate for NIR interferometry observations. We aim to resolve, spatiallyExpand
The study of unclassified B[e] stars and candidates in the Galaxy and Magellanic Clouds†
We investigated 12 unclassified B[e] stars or candidates, 8 from the Galaxy, 2 from the Large Magellanic Cloud (LMC) and 2 from the Small Magellanic Cloud (SMC). Based on the analysis ofExpand
Time-dependent spectral-feature variations of stars displaying the B[e] phenomenon - III. HD 50138
Context. B[e] stars are anomalous objects around which extended circumstellar matter is present. The observed properties of the central star are significantly affected by the surrounding material.Expand
An ultraviolet study of B[e] stars: evidence for pulsations, luminous blue variable type variations and processes in envelopes
Stars that exhibit a B[e] phenomenon comprise a very diverse group of objects in a different evolutionary status. These objects show common spectral characteristics, including the presence of BalmerExpand
A disk asymmetry in motion around the B[e] star MWC158
MWC158 is a star with the B[e] phenomenon that shows strong spectrophotometric variability (in lines and in UV and visible continuum) attributed to phases of shell ejection. The evolutionary stage ofExpand
On the Nature of the Herbig B[e] Star Binary System V921?Scorpii: Discovery of a Close Companion and Relation to the Large-scale Bipolar Nebula
Belonging to the group of B[e] stars, V921 Scorpii is associated with a strong infrared excess and permitted and forbidden line emission, indicating the presence of low- and high-densityExpand


On the evolutionary stage of the unclassified B[e] star CD-42°11721†
The star CD-42 ◦ 11721 is a curious B[e] star sometimes pointed as an evolved B[e] supergiant and sometimes as a young HAeBe star, due to very uncertain or even unknown stellar parameters, especiallyExpand
Hα spectropolarimetry of B[e] and Herbig Be stars
We present the results of medium resolution (�v� 60 km s 1 ) spectropolarimetric observations across Hof a sample of B(e) and Herbig Be objects. A change in linear polarization across His detected inExpand
BCD spectrophotometry of stars with the B[e] phenomenon. I. Fundamental parameters
Low resolution spectra in the $\lambda\lambda3500{-}4600$ Awavelength range of 23 stars with the B[e] phenomenon are presented. Spectral classification of 15 program stars was performed using the BCDExpand
Near-IR and visible interferometry of Be stars: Constraints from wind models
We report theoretical HI visible and near-IR line profiles, i.e. Hα (6562 A), Hβ (4861 A) and Brγ (21 656 A), and intensity maps for a large set of parameters (density, temperature, envelopeExpand
The First Ultraviolet and Optical Spectropolarimetry of the B[e] Star HD 50138
We report the first ultraviolet spectropolarimetry of the B[e] star HD 50138, obtained with the Wisconsin Ultraviolet Photo-Polarimeter Experiment aboard the Astro-2 Space Shuttle mission in 1995Expand
Be stars. V. HD 50138 = MWC 158
On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 3738-10232 A of theExpand
Parameters of galactic early B supergiants. The influence of the wind on the interstellar extinction
Context. The interstellar extinction, $E(B-V)$, of OB supergiants is usually derived from the observed color index, $(B-V)$, in comparison with the intrinsic one. This method works properly only ifExpand
The B[e] phenomenon is defined as the simultaneous presence of low-excitation forbidden line emission and strong infrared excess in the spectra of early-type stars. It was discovered in our Galaxy 30Expand
A photometric catalogue of southern emission-line stars ?;??
We present a catalogue of previously unpublished optical and infrared photometry for a sample of 162 emission-line objects and shell stars visible from the southern hemisphere. The data were obtainedExpand
Model atmospheres for G, F, A, B, and O stars
A grid of LTE model atmospheres is presented for effective temperatures ranging from 5500 to 50,000 K, for gravities from the main sequence down to the radiation pressure limit, for abundances solar,Expand