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 Hβ 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 Aql) shows similar continuum distributions (and implied mass accretion rates) but large differences in high excitation lines (HeII1640,4686;CIV1550).