Identification of two southern X-ray emitting cataclysmic variables

Journal Article · Mon Dec 01 04:00:00 EST 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164770· OSTI ID:6483995

Tuohy, I R; Buckley, D A.H.; Remillard, R A; Bradt, H V; Schwartz, D A

The optical identification of two faint HEAO 1 X-ray sources with previously uncataloged cataclysmic variables is reported. The two cataclysmic variables, 1H 0542 - 407 and H0534 - 581, have average V magnitudes of about 15.7 and about 14.9, and have similar high excitation spectra with moderate to strong He II 4686 A emission. X-ray measurements and multicolor optical photometry for both objects establish 1H 0542 - 407 as a new DQ Herculis magnetic variable having a white dwarf rotation period of about 1920 s and an orbital period near 6.2 hr. 1H 0542 - 407 is unusual among DQ Her systems in having a large soft X-ray pulse fraction of about 70 percent semiamplitude below 1 keV. No definitive X-ray or optical periodicities were detected from H0534 - 581, but it appears to be either a nova-like variable or a DQ Her system. Both cataclysmic variables have very hard X-ray spectra, with evidence for iron line emission at about 6.7 keV from 1H 0542 - 407. 42 references.

• Research Organization: Mount Stromlo and Siding Spring Observatories, Canberra, Australia; MIT, Cambridge, MA; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA
• OSTI ID: 6483995
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 311; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
ERUPTIVE VARIABLE STARS
IONIZING RADIATIONS
MATHEMATICS
PHOTOMETRY
RADIATIONS
SPECTROSCOPY
STARS
STELLAR RADIATION
TIME-SERIES ANALYSIS
VARIABLE STARS
X RADIATION