BZ Camelopardalis during its 1999/2000 optical low state

We report optical observations of the VY Scl star BZ Cam during its previous optical low state in 1999/2000. We nd drastic variations in the line proles. Narrow-band imaging observations show that its nebula extends farther than previously known and seems to be composed of two components. We determine the (O III) line intensity of BZ Cam's nebula to 4:8 10 13 erg/cm 2 /s. We discover a proper motion of BZ Cam of 25 2 mas/yr which together with the systemic radial velocity yields a space velocity of 125 km s 1 . We re-interpret the nebula as being photo-ionized by hypothesized transient, luminous, supersoft X-ray emission during optical low states, and shaped by the transverse motion of BZ Cam.

[1]  J. Greiner.  Catalog of supersoft X-ray sources , 2000, astro-ph/0005238.

[2]  G. L. Wycoff,et al.  The AC 2000: The Astrographic Catalogue on the System Defined by the Hipparcos Catalogue , 1998 .

[3]  T. Naylor,et al.  High-Speed Optical Spectroscopy of a Cataclysmic Variable Wind: BZ Camelopardalis , 1997, astro-ph/9710021.

[4]  Wolfgang Voges,et al.  Identification of a complete sample of northern ROSAT All-Sky Survey X-ray sources - II. The optical observations , 1997 .

[5]  S. Rappaport,et al.  Time-dependent Calculations of Ionization Nebulae Surrounding Supersoft X-Ray Sources , 1996 .

[6]  J. Thorstensen,et al.  Periods and Quasiperiods in the Cataclysmic Variable BZ Camelopardalis , 1996 .

[7]  M. Livio,et al.  The Nature of the Supersoft X-Ray Source RX J0513-69 , 1996, astro-ph/9605090.

[8]  L. Macri,et al.  Ionization Nebulae Surrounding CAL 83 and Other Supersoft X-ray Sources , 1995 .

[9]  R. Malina,et al.  Ionization nebulae surrounding supersoft X-ray sources , 1994 .

[10]  J. M. Hollis,et al.  The 0623 + 71 bow shock nebula , 1992 .

[11]  Manfred W. Pakull,et al.  Is N44C a fossil X-ray ionized nebula? , 1989, Nature.

[12]  P. Szkody,et al.  OBSERVED LOW STATES IN DQ HERCULIS SYSTEMS , 1988 .

[13]  J. Hutchings,et al.  THE ORBIT OF THE (OLD NOVA ?) CATACLYSMIC VARIABLE 0623+71. , 1985 .

[14]  H. Bond,et al.  A SEARCH FOR FAINT PLANETARY NEBULAE ON PALOMAR SKY SURVEY PRINTS. , 1984 .

[15]  Fionn Murtagh,et al.  1st ESO/ST-ECF Data Analysis Workshop, Garching, 17-19 April 1989 : proceedings , 1989 .