Volume 378, Number 1, October IV 2001
|Page(s)||L17 - L20|
|Published online||15 October 2001|
Binaries discovered by the SPY project
I. HE 1047-0436: A subdwarf B + white dwarf system
Dr. Remeis-Sternwarte, Astronomisches Institut der Universität Erlangen-Nürnberg, Sternwartstr. 7, 96049 Bamberg, Germany
2 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
Corresponding author: R. Napiwotzki, email@example.com
Accepted: 31 August 2001
In the course of our search for double degenerate binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY -SPY) we discovered that the sdB star HE 1047-0436 is radial velocity variable. The orbital period of 1.213253 d, a semi-amplitude of 94 km s-1, and a minimum mass of the invisible companion of are derived from the analysis of the radial velocity curve. We use an upper limit on the projected rotational velocity of the sdB star to constrain the system inclination and the companion mass to , bringing the total mass of the system closer to the Chandrasekhar limit. However, the system will merge due to loss of angular momentum via gravitational wave radiation only after several Hubble times. Atmospheric parameters and metal abundances are also derived. The resulting values are typical for sdB stars.
Key words: stars: early-type / binaries: spectroscopic / stars: fundamental parameters / white dwarfs
© ESO, 2001
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