Post-Common-Envelope Binary Stars and the Precataclysmic Binary PG 1114+187

We present orbit-resolved spectroscopy and orbit-sampled photometry of the binary system PG 1114+187. Both photometry and radial velocity studies reveal a period P = 1.75992 days, which is taken to be the orbital period of the binary. Strong modulation of emission-line strength with the same period is also present. A preliminary mass ratio, M2/M1 ≈ 0.7, is found from primary- and secondary-star radial velocity amplitudes. No evidence is seen for either an accretion disk or mass transfer, leading to the conclusion that PG 1114+187 is not a cataclysmic variable (CV) but is in a pre-CV state, before the initiation of mass transfer. The short orbital period also leads to the conclusion that the system passed through a common-envelope phase at some time in the past. The current list of known post–common-envelope and precataclysmic binary stars is also reviewed and the general properties of this class of star are discussed.

[1]  J. Wood,et al.  Spectroscopic observations of post-common envelope binaries , 1999 .

[2]  Martin A. Barstow,et al.  The mass, temperature and distance of the white dwarf in V471 Tauri , 1997 .

[3]  Tim Naylor,et al.  Photometry of the post-common-envelope binary PG 0308 + 096 , 1996 .

[4]  J. Scargle.  Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced data , 1982 .

[5]  M. Livio,et al.  The orbital parameters of three new subdwarf B binaries , 1999 .

[6]  D. Pollacco,et al.  A preliminary analysis of the planetary nebula central star V477 Lyrae , 1994 .

[7]  S. Baliunas,et al.  A Prescription for period analysis of unevenly sampled time series , 1986 .

[8]  J. Thorstensen,et al.  The Post-Common Envelope and Pre-Cataclysmic Binary PG 1224+309 , 1998, astro-ph/9811372.

[9]  D. Ferguson,et al.  The spectacular emission-line reflection effect of BE Ursae Majoris , 1994 .

[10]  R. Taam,et al.  The Disrupted Magnetic Braking Hypothesis and the Period Gap of Cataclysmic Variables , 1989 .

[11]  Mario Livio,et al.  Close Binary White Dwarf Systems: Numerous New Detections and Their Interpretation , 1998, astro-ph/9802356.

[12]  J. Wood,et al.  Spectroscopy of the post-common envelope binary HW Virginis , 1999 .

[13]  T. Marsh,et al.  IUE spectra of the eclipsing binary NN Serpentis , 1991 .

[14]  John R. Thorstensen,et al.  Stellar Masses, Kinematics, and White Dwarf Composition for Three Close DA+dMe Binaries , 1999 .

[15]  A. Henden,et al.  SECONDARY PHOTOMETRIC STANDARDS FOR NORTHERN CATACLYSMIC VARIABLES AND RELATED OBJECTS , 1997 .

[16]  R. Hilditch,et al.  Direct optical observations of the secondary component of UU Sagittae. , 1994 .

[17]  J. Liebert,et al.  Masses and Other Parameters of the Post-Common Envelope Binary BE Ursae Majoris , 1999 .

[18]  James Liebert,et al.  Spectroscopic observations of the detached binary PG 1413 + 015 , 1993 .

[19]  J. Liebert,et al.  The close binary central star of the planetary nebula Abell 41: a helium-rich subdwarf primary , 1984 .

[20]  A. Tokovinin.  Orbits of new spectroscopic components in 7 multiple systems , 1997 .

[21]  J. Liebert,et al.  The Palomar-Green Catalog of Ultraviolet-Excess Stellar Objects , 1986 .

[22]  T. Marsh,et al.  A DETACHED WHITE DWARF/M DWARF BINARY WITH AN ORBITAL PERIOD OF 2.47 H , 1996 .

[23]  M. Livio,et al.  Binary system parameters and the hibernation model of cataclysmic variables , 1987 .

[24]  H. Bond,et al.  The precataclysmic nucleus of Abell 41 , 1983 .

[25]  M. Livio,et al.  Morphologies of Planetary Nebulae Ejected by Close-Binary Nuclei , 1990 .

[26]  A. Bruch.  The Precataclysmic Binary RR Caeli Revisited: Spectroscopy and Light-Curve Synthesis , 1999 .

[27]  R. Wade,et al.  PG 0308+096 and PG 1026+002: two new short period binary stars resulting from common-envelope evolution , 1993 .

[28]  A. Shafter,et al.  Time-resolved CCD photometry of a sample of Palomar-green cataclysmic variable candidates , 1995 .

[29]  Martin A. Barstow,et al.  RE 0720-318: a pre-cataclysmic binary system with a DAO white dwarf primary , 1995 .

[30]  Ronald A. Downes,et al.  A CATALOG AND ATLAS OF CATACLYSMIC VARIABLES-SECOND EDITION , 1997 .

[31]  J. Thorstensen,et al.  Spectroscopic, orbital, and physical properties of the binary Feige 24 and detection of transient He II absorption in the system , 1994 .

[32]  P. Giommi,et al.  The Discovery of 13 second X-Ray Pulsations from the Hydrogen-depleted Subdwarf O6 Star Binary HD 49798 , 1996, astro-ph/9610139.

[33]  Martin A. Barstow,et al.  The orbital period of the pre-cataclysmic binary RE 2013+400 and a study of the atmosphere of the DAO white dwarf primary , 1995 .

[34]  B. Warner.  Cataclysmic Variable Stars by Brian Warner , 1995 .

[35]  R. K. Honeycutt,et al.  CCD ENSEMBLE PHOTOMETRY ON AN INHOMOGENEOUS SET OF EXPOSURES , 1992 .

[36]  M. Shara,et al.  A CATALOG OF CATACLYSMIC VARIABLES , 1993 .