Effective temperature vs. line-depth ratio for ELODIE spectra: Gravity and rotational velocity effects

The dependence on the temperature of photospheric line-depth ratios (LDRs) in the spectral range 6190-6280 angstrom is investigated by using a sample of 174 ELODIE Archive stellar spectra of luminosity class from V to III. The rotational broadening effect on LDRs is also studied. We provide useful calibrations of effective temperature versus LDRs for giant and main sequence stars with 3800 less than or similar to T-eff less than or similar to 6000 K and v sin i in the range 0-30 km s(-1). We found that, with the exception of very few line pairs, LDRs, measured at a spectral resolution as high as 42 000, depend on v sin i and that, by neglecting the rotational broadening effect, the T-eff determination can be wrong by similar to 100 K in the worst cases. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim.