A photometric and spectroscopic comparison of the cataclysmic variables on the 2 sides of the period gap and at a specific orbital period

Abstract

New and previously existing photometric colors and spectroscopic H and He line strengths are used to compare CV disk systems below the period gap (P=80–130 min) with those directly above (P=190–240 min). Significant differences are found in the mean U-B, V-J colors and in the Hß equivalent widths on the 2 sides of the gap. A detailed comparison from UV-IR of 3 high inclination novalike systems with periods near 3.3 hr (PG1012-029, PG1030+590 and V1315 Aq1) shows similar continuum distributions (and implied mass accretion rates) but large differences in high excitation lines (HeII1640, 4686; CIV1550).