X-ray Pulsations in the Supersoft X-ray Binary CAL 83

Abstract

X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4 minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations the white dwarf. This is the first detection of pulsations in a classical supersoft X-ray binary.Comment: revised text; 11 pages and 3 figures; accepted for publication in the Astronomical Journa