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Spectral atlas of massive stars around He I 10830 Angstrom

Groh, J. H., Damineli, A., Jablonski, F. 2007, A&A, 465, 993

Based on observations made at Observatorio do Pico dos Dias/LNA (Brazil), we constructed a digital atlas of peculiar, high-luminosity massive stars in the near-infrared region (10470-11 000 Å) at medium resolution (R≃7000). The atlas displays the spectra of massive stars organized in four categories, namely Be stars, OBA Iape (or luminous blue variables, LBV candidates and ex/dormant LBVs), OB supergiants and Wolf-Rayet stars. The spectra are centered around He I 10 830 Å, which is formed in the wind of those stars, and is a crucial line to obtain their physical parameters. The instrumental configuration also sampled a rich variety of emission lines of Fe II, Mg II, C I, N I, and Pa γ. We propose that two unidentified absorption features have interstellar and/or circumstellar origin. For the strongest one (10780 Å) an empirical calibration between E(B-V) and equivalent width was derived. Selected LBVs were observed in different epochs from 2001 to 2004, and their spectral variability reveals that some stars, such as η Car, AG Car and HR Car, suffered dramatic spectroscopic changes during this time interval.