Discovery of magnetic fields in hot subdwarfs

¹ Dr. Remeis-Sternwarte, Astronomisches Institut der Universität Erlangen-Nürnberg, Sternwartstr. 7, Bamberg 96049, Germany e-mail: otoole@sternwarte.uni-erlangen.de
² Astronomisches Rechen-Institut, Mönchhofstr. 12-14, 69221 Heidelberg, Germany
³ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr., 85748 Garching, Germany

Received: 16 December 2004
Accepted: 4 March 2005

Abstract

We present polarisation measurements of sdB and sdO stars using FORS1 on the VLT. The observations were made as part of a project to determine whether magnetic fields in two super-metal-rich stars can explain their extreme abundance peculiarities. Field strengths of up to ~1.5 kG range have been measured at varying levels of significance in each of our six targets, however no clear evidence was found between apparently normal subdwarfs and the metal-rich objects. The origin of the magnetic fields is unknown. We also discuss the implications of our measurements for magnetic flux conservation in late stages of stellar evolution.