Light element non-LTE abundances of λ Bootis stars. I. Carbon and oxygen

Autor(en)

Ernst Paunzen, Inga Kamp, I. Kh. Iliev, Ulrike Heiter, M Hempel, Werner Wolfgang Weiss, Ina S. Barzova, Florian Kerber, Peter Mittermayer

Abstrakt

Abundances for the light elements of {lambda Bootis} stars are a main
key to understand the astrophysical processes behind the so-called
{lambda Bootis} phenomenon. These stars are characterized by a typical
abundance pattern (strong underabundances of the Fe-peak elements
whereas the light elements have apparently solar abundances) which is
still based mainly on LTE-calculations. Therefore we started an
investigation to derive accurate abundances of the light elements (C, N,
O and S). For this purpose a new oxygen model atom was implemented in
the Kiel non-LTE code. High resolution and high signal-to-noise spectra
were used. For each element only a single wavelength region with lines
of the specific element was selected and observed in order to avoid
contamination from other elements. In the first paper we present
abundances for carbon and oxygen of a statistically significant number
of well established {lambda Bootis} stars. The second paper will deal
with nitrogen and sulphur. The most important result is that on average
carbon is less abundant than oxygen but still both elements are
significant more abundant than the Fe-peak elements. Furthermore the
anticorrelation of carbon and oxygen with the silicon abundance is
proven, which strongly supports the accretion/diffusion theory. Based on
observations obtained at ESO-La\,Silla and BNAO Rozhen

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Bulgarian Academy of Sciences (BAS), Leopold-Franzens-Universität Innsbruck, Christian-Albrechts-Universität zu Kiel

Journal

Astronomy & Astrophysics

Band

345

Seiten

597-604

Anzahl der Seiten

8

ISSN

0004-6361

Publikationsdatum

1999

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/light-element-nonlte-abundances-of--bootis-stars-i-carbon-and-oxygen(1a869aa8-855e-4e68-89cf-44f2dbb6cad5).html