Forum Springer Astron. Astrophys.
Forum Whats New Search Orders

Astron. Astrophys. 346, 151-157 (1999)

Table of Contents
Available formats: HTML | PDF | (gzipped) PostScript

SW Ursae Majoris, CU Velorum and AH Mensae: three more accreting white dwarfs unveiled? *

B.T. Gänsicke 1 and D. Koester 2

1 Universitäts-Sternwarte, Geismarlandstr. 11, D-37083 Göttingen, Germany
2 Institut für Theoretische Physik und Astrophysik der Universität Kiel, D-24098 Kiel, Germany

Received 2 February 1999 / Accepted 12 March 1999


We present IUE spectroscopy of the three cataclysmic variables SW UMa, CU Vel, and AH Men. In all three systems, a broad [FORMULA] absorption profile is observed. In the two short-period dwarf novae SW UMa and CU Vel, the SWP flux is interpreted as photospheric emission from white dwarfs with effective temperatures of 16 000 K and 18 500 K, respectively, similar to the well-studied systems WZ Sge and VW Hyi. From the white dwarf temperatures derived in short period dwarf novae to date, there is no significant difference between the supposedly old, low-mass-transfer TOADs and the "normal" SU UMa dwarf novae.

In the case of the novalike variable AH Men, the interpretation of the IUE data is not unambiguous. The SWP spectrum closely resembles that of a [FORMULA] K white dwarf, but this interpretation is in conflict with the distance [FORMULA] pc which we derive from the published optical spectrum. The SWP spectrum can alternatively be explained by emission from an accretion disc with a moderate mass transfer rate ([FORMULA] [FORMULA] yr-1) seen at a low inclination ([FORMULA]). The possible contribution of the white dwarf to the observed UV flux cannot be determined quantitatively from the poor IUE spectrum, but may be as high as 50 %.

Key words: stars: novae, cataclysmic variables – stars: white dwarfs – stars: atmospheres – stars: individual: SW UMa – stars: individual: CU Vel – stars: individual: AH Men

* Based on observations made with the International Ultraviolet Explorer, retrieved from the IUE FA.

Send offprint requests to: B. Gänsicke (boris@uni-sw.gwdg.de)

© European Southern Observatory (ESO) 1999

Online publication: May 6, 1999