The pre-cataclysmic variable, LTT 560
Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica, Vicuña Mackenna 4860, 782-0436 Macul, Chile e-mail: firstname.lastname@example.org
2 Department of Physics, University of Warwick, Coventry CV4 7AL, UK e-mail: [Boris.Gaensicke;a.aungwerojwit]@warwick.ac.uk
3 European Southern Observatory, Casilla 19001, Santiago 19, Chile e-mail: email@example.com
4 Department of Physics, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand
5 Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción, Chile e-mail: firstname.lastname@example.org
6 Institut für Theoretische Physik und Astrophysik, University of Kiel, 24098 Kiel, Germany e-mail: email@example.com
Accepted: 11 August 2007
Aims. System parameters of the object LTT 560 are determined in order to clarify its nature and evolutionary status.
Methods. We apply time-series photometry to reveal orbital modulations of the light curve, time-series spectroscopy to measure radial velocities of features from both the primary and the secondary star, and flux-calibrated spectroscopy to derive temperatures of both components.
Results. We find that LTT 560 is composed of a low temperature (T ~ 7500 K) DA white dwarf as the primary and an M5.5±1 main-sequence star as the secondary component. The current orbital period is Porb = 3.54(07) h. We derive a mass ratio = 0.36(03) and estimate the distance to d = 25–40 pc. Long-term variation of the orbital light curve and an additional Hα emission component on the white dwarf indicate activity in the system, probably in the form of flaring and/or accretion events.
Key words: binaries: close / stars: late-type / white dwarfs / novae, cataclysmic variables
© ESO, 2007