CAOSP abstracts, Volume: 38, No.: 2, year: 2008

Abstract: A brief discussion of earlier determinations of effective temperatures of chemically peculiar stars is given. It is stressed that the effective temperature is a global parameter, important for stellar structure and evolution studies. It should, however, be used with caution in atmospheric investigations. New determinations of effective temperatures of 27 chemically peculiar stars with characteristics typical of magnetic variables were obtained from a root-mean-square fit of metal enhanced model atmospheres to the observed and de-reddened, when necessary, spectral energy distributions (SED) from UV to red. Metallicity and effective temperature were used as fitting parameters, assuming fixed values of gravity: log g = 4 for main sequence stars and log g = 3 for giants. Equal weights were given to the UV and visual part of SED. The quality of fit was checked for each star by determination of the temperature from the best fitting model atmosphere to the UV part and to the visual part of SED separately. Both temperatures should be close to one another if the global best fitting model satisfactorily describes the full observed SED. This is the case for about a half of the investigated stars but the difference exceeds 750 K for the remaining stars with the extreme values above 2000 K. Possible reasons for such discrepancies are discussed. New, revised calibrations of effective temperature and bolometric correction of magnetic stars in terms of reddening free Strömgren indices are given. It is shown that the investigated stars populate uniformly the main sequence.

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Last update: April 17, 2008