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A&A Supplement Series, Vol. 126, December I 1997, 251-255

Received January 6; accepted February 27, 1997

The precision of spectroscopic luminosity in A-F type stars and the classification of Am stars

C. Jaschek and A. Valbousquet

Send offprint request: C. Jaschek, 37 Teso de la Feria 37008 Salamanca, Spain.
Observatoire de Strasbourg, URA 1280 CNRS, 11 rue de l'Université, 67000 Strasbourg, France


We analyze the work of three teams of classifiers providing spectral classifications in the range of late B-type to early F-type stars. With the help of a statistical model we derive an accuracy of tex2html_wrap_inline852 luminosity classes for the spectroscopic luminosity class provided by classifiers. This is sligthly better than one luminosity class, and corresponds, in the region of the A-type stars, to a precision of about tex2html_wrap_inline854 (absolute) magnitudes. We do not find differences in the precision of three series analyzed.

We analyze also the case of Am stars and conclude that the probability that two independent classifiers agree that a given object is Am, is of the order of 60%.

keywords: stars: distances -- stars: fundamental parameters -- stars: HR diagram

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