AMBER/VLTI and MIDI/VLTI spectro-interferometric observations
 of the B[e] supergiant CPD$-57\mathrm{^\circ}\,2874$

Souza, A. Domiciano de; Driebe, T.; Chesneau, O.; Hofmann, K.-H.; Kraus, Stefan; Мирошниченко, А. С.; Ohnaka, K.; Petrov, R.; Preibisch, Thomas; Stee, Philippe; Weigelt, G.; Lisi, F.; Malbet, Fabien; Richichi, A.

doi:10.1051/0004-6361:20054134

Cited by 48 publications

(36 citation statements)

References 22 publications

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“…The ejected material of B[e]SGs shows two different regions: a fast polar wind structure and either a Keplerian or slow expanding equatorial disc or ring. The disc configuration has been confirmed by polarimetric and interferometric observations (Magalhaes 1992;Oudmaijer & Drew 1999;Melgarejo et al 2001;Magalhães et al 2006;Domiciano de Souza et al 2007;Millour et al 2011;Cidale et al 2012). These discs provide ideal conditions for molecule formation and dust condensation (Kraus et al 2000;Stahl 2001).…”

Section: Introductionmentioning

confidence: 71%

Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

Torres

Cidale

Kraus

et al. 2018

A&A

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Context. B[e] supergiants are massive post-main-sequence stars, surrounded by a complex circumstellar environment where molecules and dust can survive. The shape in which the material is distributed around these objects and its dynamics as well as the mechanisms that give rise to these structures are not well understood. Aims. The aim of this work is to deepen our knowledge of the structure and kinematics of the circumstellar disc of the B[e] supergiant LHA 120-S 35. Methods. High-resolution optical spectra were obtained in three different years. Forbidden emission lines, that contribute to trace the disc at different distances from the star, are modelled in order to determine the kinematical properties of their line-forming regions, assuming Keplerian rotation. In addition, we used low-resolution near-infrared spectra to explore the variability of molecular emission. Results. LHA 120-S 35 displays an evident spectral variability in both optical and infrared regions. The P-Cygni line profiles of H i, as well as those of Fe ii and O i, suggest the presence of a strong bipolar clumped wind. We distinguish density enhancements in the P-Cygni absorption component of the first Balmer lines, which show variations in both velocity and strength. The P-Cygni profile emission component is double-peaked, indicating the presence of a rotating circumstellar disc surrounding the star. We also observe line-profile variations in the permitted and forbidden features of Fe ii and O i. In the infrared, we detect variations in the intensity of the H i emission lines as well as in the emission of the CO band-heads. Moreover, we find that the profiles of each [Ca ii] and [O i] emission lines contain contributions from spatially different (complete or partial) rings. Globally, we find evidence of detached multiring structures, revealing density variations along the disc. We identify an inner ring, with sharp edge, where [Ca ii] and [O i] lines share their forming region with the CO molecular bands. The outermost regions show a complex structure, outlined by fragmented clumps or partial-ring features of Ca ii and O i. Additionally, we observe variations in the profiles of the only visible absorption features, the He i lines. Conclusions. We suggest that LHA 120-S 35 has passed through the red-supergiant (RSG) phase and evolves back bluewards in the Hertzsprung-Russell diagram. In this scenario, the formation of the complex circumstellar structure could be the result of the windwind interactions of the post-RSG wind with the previously ejected material from the RSG. The accumulation of material in the circumstellar environment could be attributed to enhanced mass-loss, probably triggered by stellar pulsations. However, the presence of a binary companion can not be excluded. Finally, we find that LHA 120-S 35 is the third B[e] supergiant belonging to a young stellar cluster.

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Section: Introductionmentioning

confidence: 71%

Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

Torres

Cidale

Kraus

et al. 2018

A&A

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“…With these, circumstellar gas dynamics can be mapped with unprecedented spatial (milli-to micro-arcsecond) and spectral (∆ ∼ 25 km s −1 ) resolution. This has been a successful method of resolving some of the most intensely debated B[e] systems ; Domiciano de Souza et al 2007;Millour et al 2009;Weigelt et al 2011;Kraus et al 2008Kraus et al , 2012Wang et al 2012;Wheelwright et al 2012bWheelwright et al ,c, 2013. In most of these cases, binary interaction is the most probable cause of the complex circumstellar environment.…”

Section: Introductionmentioning

confidence: 99%

A resolved, au-scale gas disk around the B[e] star HD 50138

Ellerbroek

Benisty

Kraus

et al. 2014

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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.

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“…Recently, the advent of the optical long baseline interferometry using large telescopes, especially the VLT 8-m and the Keck 10-m telescopes, has made it possible to resolve, and consequently describe, the gaseous and dusty circumstellar environment of the brightest stars with the B[e] phenomenon (Domiciano de Souza et al 2007;Monnier et al 2009;Millour et al 2009;Meilland et al 2010). The high spatial resolution acquired, associated to the spectral dispersion provided by instruments like VLTI/MIDI and VLTI/AMBER makes it possible to obtain sizes, shapes, and orientations of the circumstellar material, as a function of wavelength in the near and mid-IR ranges.…”

Section: Introductionmentioning

confidence: 99%

The Galactic unclassified B[e] star HD 50138

Fernandes

Meilland

Bendjoya

et al. 2011

A&A

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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 by outbursts or shell phases. Spectropolarimetric observations have shown the presence of a non-spherically symmetric circumstellar environment that is responsible for the B[e] phenomenon. However, up to now, the structure of the circumstellar medium of this object has not been studied deeply. Aims. Based on recent optical long baseline interferometric observations from the VLTI/MIDI and VLTI/AMBER, and also from the Keck segment-tilting experiment, we study the structure of the circumstellar environment of HD 50138. Methods. The analysis of our data is based on geometrical analytical modeling, also using the recent LITpro software and considering a large space of parameters, which allows us to obtain a good estimate of the geometry of the circumstellar medium of HD 50138, responsible for the emission in the H, K, and N-bands. Results. We resolve the circumstellar environment of HD 50138 and describe its geometry for the first time in detail. Through analysis of multiwavelength data, the presence of a dusty circumstellar disk with an orientation onto the sky-plane of 71 ± 7 • , which is perpendicular to the polarimetric measurements from the literature, was derived. We also derived that HD 50138 is seen under an intermediate angle related to the line of sight, 56 ± 4 • . In addition, the structure of the disk and the flux contributions of the gas and dust components is discussed. Conclusions. Based on analysis of different sets of interferometric data, we describe the circumstellar disk whose geometric parameters were determined, allowing us to understand the geometry of the circumstellar material of this bright star with the B[e] phenomenon.

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AMBER/VLTI and MIDI/VLTI spectro-interferometric observations of the B[e] supergiant CPD$-57\mathrm{^\circ}\,2874$

Cited by 48 publications

References 22 publications

Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

Resolving the clumpy circumstellar environment of the B[e] supergiant LHA 120-S 35

A resolved, au-scale gas disk around the B[e] star HD 50138

The Galactic unclassified B[e] star HD 50138

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