High resolution optical spectroscopy of an LBV-candidate inside the CygOB2 association

Abstract

For the first time, we obtained the high-resolution (R=15000 and 60000) optical spectra for the extremely luminous star No.12, associated with the IR-source IRAS20308+4104, a member of the CygOB2 association. We have found about 200 spectral features in range 4552-7939AA, including the interstellar NaI, KI lines and numerous DIBs, which are the strongest absorption lines in the spectrum, along with the HeI, CII, and SiII lines. A two-dimensional spectral classification indicates that the spectral type is B5+/-0.5 Ia+. Our analysis of the Vr data shows the presence of a Vr gradient in the stellar atmosphere, caused by the infall of matter onto the star. The strong Halpha emission displays broad Thompson wings and time-variable core absorption, providing evidence that the stellar wind is inhomogeneous, and a slightly blue-shifted PCyg type absorption profile. We concluded that the wind is variable in time.

arXiv comment20 pages, 5 figures, 2 tables

References in corpus (4)

• The Milky Way in Molecular Clouds: A New Complete CO Survey
• The Progenitor Masses of Wolf-Rayet Stars and Luminous Blue Variables Determined from Cluster Turn-offs. II. Results from 12 Galactic Clusters and OB Associations
• Observations of H3+ in the Diffuse Interstellar Medium
• Long-term spectroscopic monitoring of the Luminous Blue Variable HD160529

Cited by in corpus (12)

• On the nature of the galactic early-B hypergiants
• Unveiling the Cygnus OB2 stellar population with Chandra
• Detection of PAH Absorption and Determination of the Mid-Infrared Diffuse Interstellar Extinction Curve from the Sightline Toward Cyg OB2-12
• The first X-ray survey of Galactic Luminous Blue Variables
• A multi-epoch XMM-Newton campaign on the core of the massive Cyg OB2 association
• On the nature of high reddening of Cygnus OB2 #12 hypergiant
• A High-Resolution Study of Near-Infrared Diffuse Interstellar Bands
• On the binary nature of massive blue hypergiants: high-resolution X-ray spectroscopy suggests that Cyg OB2 12 is a colliding wind binary
• Variations on a theme -- the puzzling behaviour of Schulte 12
• To the problem of spectral mimicry of supergiants
• Medium resolution spectroscopy of the supergiant O3If* Cyg OB2 No7
• The Inhomogeneous Wind of the LBV Candidate CygOB2-No.12