Astronomy & Astrophysics

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Issue		A&A Volume 374, Number 3, August II 2001
Page(s)		957 - 967
Section		Formation, structure and evolution of stars
DOI		10.1051/0004-6361:20010645

A&A 374, 957-967 (2001)
DOI: 10.1051/0004-6361:20010645

Physical parameters of $\mathsf{\lambda}$ Bootis stars

E. Solano¹, E. Paunzen², O. I. Pintado³ and J. Varela⁴

¹ Laboratorio de Astrofísica Espacial y Física Fundamental (LAEFF), Apartado de Correos 50727, 28080 Madrid, Spain
    e-mail: esm@vilspa.esa.es
² Institut für Astronomie der Universität Wien, Türkenschanzstr. 17, 1180 Wien, Austria
    e-mail: Ernst.Paunzen@univie.ac.at
³ Departamento de Física, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán, Argentina -Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina
    e-mail: opintado@tucbbs.com.ar
⁴ IMAFF, Consejo Superior de Investigaciones Científicas, c/ Serrano 113, 28006 Madrid, Spain
    e-mail: jesusv@imaff.cfmac.csic.es

(Received 7 December 2000 / Accepted 26 April 2001 )

Abstract
This is the first of two papers whose main goal is to update and improve the information available on the physical properties of the $\lambda$ Bootis stars. The determination of the stellar parameters is of fundamental importance to shed light into the different theories proposed to explain the $\lambda$ Bootis phenomenon. With this aim, projected rotational velocities, effective temperatures, surface gravities and chemical abundances of a sample of suspected $\lambda$ Bootis stars have been calculated. Five objects showing composite spectra typical of binary systems were found in our analysis. The abundance distribution of the program stars does not resemble the chemical composition of the class prototype, $\lambda$ Boo, which poses some concerns regarding the idea of a well-defined, chemically homogeneous group of stars. A possible relation between rotational velocities and the $\lambda$ Bootis phenomenon has been found. This result would be in agreement with the accretion scenario proposed by Turcotte & Charbonneau (1993).

Key words: stars: chemically peculiar -- stars: abundances

Offprint request: E. Solano, esm@vilspa.esa.es

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Physical parameters of Bootis stars

Physical parameters of $\mathsf{\lambda}$ Bootis stars