EDP Sciences
Free access
Volume 392, Number 2, September III 2002
Page(s) 529 - 533
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20020962

A&A 392, 529-533 (2002)
DOI: 10.1051/0004-6361:20020962

A calibration of the 85 Peg binary system

J. Fernandes1, P. Morel2 and Y. Lebreton3

1  Observatório Astronómico da Universidade de Coimbra, Santa Clara, 3040 Coimbra, Portugal and Departamento de Matemática da Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Portugal
2  Département Cassini, UMR CNRS 6529, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
3  GEPI, Observatoire de Paris Meudon, 92195 Meudon, France

(Received 28 September 2001 / Accepted 11 June 2002)

We have calibrated the initial abundances, age and mixing-length parameters of the visual binary system 85 Pegasi. We obtain an age $t_{\rm 85\,Peg}=9\,345\pm500$ Myr, masses $m_{\rm A}=0.88\pm0.01\,M_\odot$ and $m_{\rm B}=0.55\pm0.02\,M_\odot$, an initial helium mass fraction $Y_{\rm i}=0.25\pm0.01$, an initial metallicity $\rm [\frac{Fe}H]_i=-0.185\pm0.054$ and mixing-length parameters $\Lambda_{\rm A}=1.80\pm0.05$ and $\Lambda_{\rm B}=2.14\pm0.10$. We find that, as already proposed, 85 Peg B is itself a binary. The mass of the unseen companion is $m_{\rm b}\approx 0.11\,M_\odot$.

Key words: stars: binaries: visual -- stars: evolution -- stars: fundamental parameters -- stars: individual: 85 Peg

Offprint request: J. Fernandes, jmfernan@mat.uc.pt

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