Six detached white-dwarf close binaries

Abstract

We determine the orbits of four double degenerate systems (DDs), composed of two white dwarfs, and of two white dwarf -- M dwarf binaries. The four DDs, WD1022+050, WD1428+373, WD1824+040, and WD2032+188, show orbital periods of 1.157155(5) d, 1.15674(2) d, 6.26602(6) d and 5.0846(3) d respectively. These periods combined with estimates for the masses of the brighter component, based on their effective temperatures, allow us to constrain the masses of the unseen companions. We estimate that the upper limit for the contribution of the unseen companions to the total luminosity in the four DDs ranges between 10 and 20 per cent. In the case of the two white dwarf - M dwarf binaries, WD1042-690 and WD2009+622, we calculate the orbital parameters by fitting simultaneously the absorption line from the white dwarf and the emission core from the M-dwarf. Their orbital periods are 0.337083(1) d and 0.741226(2) d respectively. We find signatures of irradiation on the inner face of WD2009+622's companion. We calculate the masses of both components from the gravitational redshift and the mass-radius relationship for white dwarfs and find masses of 0.75 -- 0.78 Msun and 0.61 -- 0.64 Msun for WD1042-690 and WD2009+622 respectively. This indicates that the stars probably reached the asymptotic giant branch in their evolution before entering a common envelope phase. These two white dwarf - M dwarf binaries will become cataclysmic variables, although not within a Hubble time, with orbital periods below the period gap.

16 pages, 9 figures. Accepted for publication in MNRAS

References in corpus (36)

• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• Catalogue of cataclysmic binaries, low-mass X-ray binaries and related objects (Seventh edition)
• The Formation Rate, Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey
• Population synthesis for double white dwarfs I.Close detached systems
• The Lick Planet Search: Detectability and Mass Thresholds
• Short-period AM CVn systems as optical, X-ray and gravitational wave sources
• The age, life expectancy, and space density of Post Common Envelope Binaries
• Inward Propagation of Nuclear-Burning Shells in Merging C-O and He White Dwarfs
• Orbital periods of twenty two subdwarf B stars
• A Comparative Study of the Mass Distribution of Extreme Ultraviolet-Selected White Dwarfs
• Hubble Space Telescope Spectroscopy of V471 Tauri: Oversized K Star, Paradoxical White Dwarf
• Close Binary White Dwarf Systems: Numerous New Detections and Their Interpretation
• Carbon-Oxygen White Dwarfs Accreting CO-Rich Matter I: A Comparison Between Rotating and Non-Rotating Models
• HS 0705+6700: a new eclipsing sdB binary
• Radial velocity measurements of white dwarfs
• The environment of HII galaxies
• The DA+dMe eclipsing binary EC13471-1258: its cup runneth over...just
• Photometric Observations of the Type Ia SN 2002er in UGC 10743
• A First Look at White Dwarf - M Dwarf Pairs in the Sloan Digital Sky Survey (SDSS)
• A Systematic Study Of X-Ray Variability In The ROSAT All-Sky Survey
• A detached double degenerate with a 1.4 hr orbital period
• The triple degenerate star WD1704+481
• Binaries discovered by the SPY project I. HE 1047-0436: a subdwarf B + white dwarf system
• Binaries discovered by the SPY project. II. HE 1414-0848: a double degenerate with a mass close to the Chandrasekhar limit
• The mass ratio distribution of short period double degenerate stars
• HS2237+8154: On the onset of mass transfer or entering the period gap?
• Confirmation of Eclipses in KPD 0422+5421, A Binary Containing a White Dwarf and a Subdwarf B Star
• PG1115+166 - a long period DA+DB binary
• Detection of a companion to the pulsating sdB Feige 48
• Binaries discovered by the SPY project. III. HE2209-1444: a massive, short period double degenerate
• How old is the Universe ? Setting new constraints on the age of the Universe
• Criticism of recent calculations of common envelope ejection
• The Post-Common Envelope and Pre-Cataclysmic Binary PG 1224+309
• Forever Young: High Chromospheric Activity in M subdwarfs
• Orbital periods of the binary sdB stars PG0940+068 and PG1247+554
• The rotational velocity of the sdOB primary of the eclipsing binary system LB 3459 (AA Dor)

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