1H 0551-819 : discovery of a new cataclysmic variable from the HEAO-1 survey.
Abstract
We report the discovery of a cataclysmic variable that was detected as an X-ray source by the HEAO-1 modulation collimator. The spectrum is typical of a weaklined novalike system, with moderately strong He II 4686-A emission and a very blue continuum. Extensive photometric observations (about 94 h in total) from 1989 February to 1990 March reveal the presence of a 3.34-h quasi-sinusoidal, 5-percent modulation. We confirm with a radial velocity study that this variation occurs at, or very near to, the orbital period. Furthermore, the relative phasing of the photometry and emission-line velocities, and the light curve structure, points to a similar origin to that proposed for several other X-ray-selected CVs (e.g., AO Psc and FO Aqr), namely, an X-ray-illuminated disk bright-spot. This and other circumstantial evidence suggest that 1H0551-819 may be an intermediate polar. On suborbital time-scales, all of the light curves are dominated by incoherent flickering, with occasional enhancements of power at periods in the region of 600-2400 s. The short coherence, but with significant amplitude, points to a QPO-like interpretation. The usual optical signature of an intermediate polar, namely, a strong and coherent optical variation at the spin or sideband period, is lacking in 1H0551 - 819.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1993
- DOI:
- 10.1093/mnras/265.4.926
- Bibcode:
- 1993MNRAS.265..926B
- Keywords:
-
- Sky Surveys (Astronomy);
- Cataclysmic Variables;
- X Ray Sources;
- Stellar Spectra;
- Light Curve;
- Astronomical Photometry;
- Radial Velocity;
- Emission Spectra;
- Astrophysics