Multi element Doppler imaging of Ap stars: I. He, Mg, Si, Cr and Fe surface distribution for CU Virginis

Author(s)
Rainer Kuschnig, Tanya A. Ryabchikova, Nikolai E. Piskunov, Werner Wolfgang Weiss, Michael Gelbmann
Abstract

We present the distribution of helium, magnesium, silicon, chromium and iron on the surface of the fast rotating magnetic B9p Si star CU Virginis, obtained with a Doppler Imaging inversion code. A clearly defined helium spot coincides with the position of one magnetic pole whereas silicon, chromium and iron accumulate in regions where the magnetic field lines are dominantly horizontal in the stellar atmosphere. The distribution of magnesium is significantly different compared to the other elements. The Hd line varies in phase with the helium spot and the magnetic pole and the line profiles can be fitted within the observational errors with model atmospheres of constant Teff of 12500 K, but different surface gravity. We compare our observations with current concepts for diffusion in magnetic chemically peculiar stars and find good agreement.

Organisation(s)
Department of Astrophysics
External organisation(s)
Russian Academy of Sciences, Uppsala University
Journal
Astronomy & Astrophysics
Volume
348
Pages
924-932
No. of pages
9
ISSN
0004-6361
Publication date
1999
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy
Portal url
https://ucrisportal.univie.ac.at/en/publications/multi-element-doppler-imaging-of-ap-stars-i-he-mg-si-cr-and-fe-surface-distribution-for-cu-virginis(ce18c813-6728-4b7d-8ae2-66e10874547a).html