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A study of two post-common envelope binary systems
- Source :
- Monthly Notices of the Royal Astronomical Society. 359:315-327
- Publication Year :
- 2005
- Publisher :
- Oxford University Press (OUP), 2005.
-
Abstract
- We present intermediate-resolution, phase-resolved spectra of the close-binary systems EC 11575-1845 and V664 Cas, the central star of the planetary nebula HFG 1. Both systems have a very rich emission-line spectrum originating from the face of the cool star, which is irradiated by the hot subdwarf star. The H 1 emission lines are wide, consistent with Stark broadening. These have a complex shape due to strong absorption near the line centre. We report on new spectroscopic orbits for both subdwarf stars, based on radial velocity measurements of their He II lines. The orbits of the heated face of the cool companions were measured from narrow emission lines, and from the wide H I profiles; some differences were found between ions. At phases around 0, absorption lines from the photosphere of the secondary star of V664 Cas are seen. These are used to estimate a spectral type of mid-F to early K, and we report on their radial velocities. Synthetic spectra from the non-local thermodynamic equilibrium model atmospheres were used to fit features in the optical spectrum of the hot subdwarf star of EC 11575-1845, from which we estimate T eff = 105 000 ± 20000 K, logg = 6.7 ± 0.3, log n He /n H = -0.8 ± 0.1. Finally, we consider the most likely range of component masses for these two systems.
- Subjects :
- Physics
Photosphere
Astronomy
White dwarf
Astronomy and Astrophysics
Astrophysics
Subdwarf
Spectral line
Radial velocity
Common envelope
Space and Planetary Science
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Emission spectrum
Stellar evolution
Astrophysics::Galaxy Astrophysics
Subjects
Details
- ISSN :
- 13652966 and 00358711
- Volume :
- 359
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi...........a01816678354a801d8873ddcfe38b9e1