DOI: 10.1051/0004-6361:20053905
Abundance analysis of 5 early-type stars in the young open cluster IC 2391
Ch. Stütz1, 2, S. Bagnulo2, E. Jehin2, C. Ledoux2, R. Cabanac3, C. Melo2 and J. V. Smoker2, 41 Institute of Astronomy (IfA), University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
2 European Southern Observatory, Casilla 19001, Santiago 19, Chile
3 Canada-France-Hawaii Telescope Corporation, 65-1238 Mamalahoa Hwy. Kamuela, Hawaii 96743, USA
4 Astrophyisics & Planetary Science Research Division, Department of Physics and Astronomy, The Queen's University of Belfast, University Road, Belfast, BT7 1NN, UK
(Received 25 July 2005 / Accepted 23 January 2006)
Abstract
Aims.It is unclear whether chemically peculiar stars of the upper main
sequence represent a class completely distinct from normal A-type
stars, or whether there exists a continuous transition from the normal
to the most peculiar late F- to early B-type stars. A systematic
abundance analysis of open cluster early-type stars would help to
relate the observed differences of the chemical abundances of the
photospheres to other stellar characteristics, without being concerned
by possible different original chemical composition. Furthermore, if a
continuous transition region from the very peculiar to the so called
normal A-F stars exists, it should be possible to detect objects with
mild peculiarities.
Methods.As a first step of a larger project, an abundance analysis of 5 F-A
type stars in the young cluster IC 2391 was performed using high
resolution spectra obtained with the UVES instrument of the ESO VLT.
Results.Our targets seem to follow a general abundance pattern: close to
solar abundance of the light elements and iron peak elements, heavy
elements are slightly overabundant with respect to the sun, similar to
what was found in previous studies of normal field A-type stars of the
galactic plane. We detected a weakly chemically peculiar star,
HD 74044. Its element pattern contains characteristics of CP1 as well
as CP2 stars, enhanced abundances of iron peak elements and also
higher abundances of Sc, Y, Ba and Ce.
We did not detect a magnetic field in this star (detection limit was 2 kG).
We also studied the star SHJM 2, proposed as a pre-main sequence object in
previous works. Using spectroscopy we found a high surface gravity, which
suggests that the star is very close to the ZAMS.
Key words: Galaxy: open clusters and associations: individual: IC 2391 -- stars: abundances -- stars: evolution -- stars: chemically peculiar -- stars: pre-main sequence
SIMBAD Objects
© ESO 2006

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