Spectropolarimetry of V1315 Aql

Abstract

Recent years have seen the emergence of a group of nova-like variables which exhibit remarkably similar behaviour. To date, there exist five such well-studied systems: V1315 Aql (Downes et al. 1986; Dhillon, Marsh and Jones 1991), SW Sex (Penning et al. 1984; Honeycutt, Schlegel and Kaitchuck 1986), DW UMa (Shafter, Hessman and Zhang 1988; Dhillon, Jones and Marsh 1994), BH Lyn (Thorstensen, Davis and Ringwald 1991; Dhillon et al. 1992) and PX And (Thorstensen et al. 1991; Still, Dhillon and Jones 1994). All five objects are eclipsing systems with orbital periods lying in the narrow range of 3.24 to 3.74 hr; all five objects exhibit single-peaked Balmer and HeI emission lines which remain largely unobscured during primary eclipse and which show strong absorption features around the inferior conjunction of the emission-line source; all five objects show single-peaked high-excitation emission lines which are eclipsed by the secondary; and all five objects show radial velocity curves with significant phase shifts relative to photometric conjunction. In addition, a number of systems are believed to be related to these five, exhibiting some, but not all, of the above features: WX Ari (Beuermann et al. 1992), UU Aqr (Diaz and Steiner 1991) and LB1800 (Buckley et al. 1990).