Aungwerojwit, A. (Amornrat), Gänsicke, B. T. (Boris T.), Rodriguez-Gil, P., Hagen, H.-J., Giannakis, O., Papadimitriou, C., Prieto, C. Allende and Engels, D.. (2007) HS 1857+5144: a hot and young pre-catalysmic variable. Astronomy & Astrophysics, Vol.469 (No.1). pp. 297-305. ISSN 0004-6361

Full text not available from this repository.

Abstract

Aims. We report the discovery of a new white dwarf/M dwarf binary, HS 1857+5144, identified in the Hamburg Quasar Survey (HQS). Methods. Time-resolved optical spectroscopy and photometry were carried out to determine the properties of this new cataclysmic variable progenitor (pre-CV). Results. The light curves of HS 1857+5144 display a sinusoidal variation with a period of P-orb = 383.52 min and peak-to-peak amplitudes of 0.7 mag and 1.1 mag in the B-band and R-band, respectively. The large amplitude of the brightness variation results from a reflection effect on the heated inner hemisphere of the companion star, suggesting a very high temperature of the white dwarf. Our radial velocity study confirms the photometric period as the orbital period of the system. A model atmosphere fit to the spectrum of the white dwarf obtained at minimum light provides limits to its mass and temperature of M-wd similar or equal to 0.6-1.0 M-circle dot and T-wd similar or equal to 70 000-100 000 K, respectively. The detection of He II lambda.4686 absorption classifies the primary star of HS 1857+5144 as a DAO white dwarf. Combining the results from our spectroscopy and photometry, we estimate the mass of the companion star and the binary inclination to be M-sec similar or equal to 0.15-0.30 M-circle dot and i similar or equal to 45 degrees-55 degrees, respectively. Conclusions. We classify HS 1857+5144 as one of the youngest pre- CV known to date. The cooling age of the white dwarf suggests that the present system has just emerged from a common envelope phase similar to 10(5) yr ago. HS 1857+5144 will start mass transfer within or below the 2-3 h period gap.

Item Type:	Journal Article
Subjects:	Q Science > QB Astronomy
Divisions:	Faculty of Science > Physics
Journal or Publication Title:	Astronomy & Astrophysics
Publisher:	EDP Sciences
ISSN:	0004-6361
Date:	July 2007
Volume:	Vol.469
Number:	No.1
Number of Pages:	9
Page Range:	pp. 297-305
Identification Number:	10.1051/0004-6361:20077276
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
URI:	http://wrap.warwick.ac.uk/id/eprint/31821

Data sourced from Thomson Reuters' Web of Knowledge

Request changes to a record

Actions (login required)

View Item