EDP Sciences
Free access
Volume 387, Number 1, May III 2002
Page(s) 151 - 161
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20020295

A&A 387, 151-161 (2002)
DOI: 10.1051/0004-6361:20020295

HR Carinae: New spectroscopic data and physical parameters

M. A. D. Machado, F. X. de Araújo, C. B. Pereira and M. B. Fernandes

Observatório Nacional-MCT, Rua José Cristino, 77, CEP 20921-400, São Cristóvão, Rio de Janeiro-RJ, Brazil

(Received 13 November 2001 / Accepted 29 January 2002 )

We present new high-resolution observations of the LBV (or S Dor variable) HR Carinae, taken with the FEROS spectrograph in the wavelength range $\lambda$ 3900-8200. The H I and Fe II lines show P Cygni profiles while the He I lines are all in absorption. Emission lines due to [N II], [O I], Na II, Mg II, Ca II and [Fe II] were also identified. Complex structures in the absorption profiles of H $\alpha$, H $\beta$ and in most of the iron lines suggest the presence of two distinct absorption regions with expansion velocities of 30 km s -1 and 100 km s -1. From a spectral analysis of the Balmer lines with a non-LTE expanding atmosphere code, we derive for HR Carinae the following parameters: $T_\star=10\,000$ K, $R_\star=350$ $R_\odot$, $\dot M=6.8$ $\times 10^{-5}$ $M_\odot$ yr -1 and He/H = 0.4. The comparison of the temperature obtained in this work with the values estimated by Nota et al. (1997) indicates that HR Carinae is moving redward across the H-R diagram on a short timescale, due to a new S Dor-phase.

Key words: stars: emission-line, Be -- stars: variables: general -- stars: individual: HR Car

Offprint request: M. A. D. Machado, dora@dage0.on.br

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