X-ray and optical spectra of the unusual cataclysmic variables LS Pegasi and T Leonis.
SZKODY P., NISHIKIDA K., LONG K.S. and FRIED R.
Abstract (from CDS):
We obtained ASCA observations of the cataclysmic variables LS Peg and T Leo in order to refine the X-ray characteristics of these two systems with unusual stream behaviors and to search for orbital features that might signify the presence of material above the orbital plane. Simultaneous (LS Peg) and contemporaneous (T Leo) optical observations showed the systems undergoing their typical stream behaviors (absorption, high-velocity component, and quasi-periodic oscillations in LS Peg; stream flow to the far side of the disk in T Leo). The X-ray light curve of LS Peg shows a low but constant count rate throughout its orbit. To fit the spectrum with a reasonable temperature requires a 7 keV partial-absorber model with high column (6x1022 cm–2). This may be evidence for material thrown high above the disk by the disk-stream interaction or a magnetic accretion funnel sometimes suggested to explain other SW Sex stars. The spectrum of T Leo is consistent with a simple 4-6 keV thermal model with lower column (3-5x1020 cm–2) and a small contribution from a cooler 1 keV component. Its light curve shows enhanced flux between phases 0.8 and 1.0, which is not due to a change in temperature or column. The difference in behavior of this light curve from that of U Gem may be due to the lower accretion in this shorter period system.
Stars: Novae, Cataclysmic Variables - Stars: Individual: Constellation Name: LS Pegasi - Stars: Individual: Constellation Name: T Leonis - X-Rays