The white dwarf revealed in the intermediate polar V709 Cassiopeiae

Abstract

Results are presented from the first detailed spectroscopic observations of the recently identified intermediate polar RXJ0028.8+5917/V709 Cas. The study of the emission line radial velocities allows us to remove the uncertainties on the different aliases of the orbital period and a best value is found at (0.2225 +/- 0.0002) day. It is also found that the system shows significant EW~ (2-4)A, broad absorptions affecting the Balmer lines from Hdelta to Hbeta. These broad absorptions are interpreted as the contribution of an underlying white dwarf atmosphere. The characteristics of the absorptions are found to be consistent with a DA log(g) = 8 white dwarf at a temperature of ~ 23 000 K, contributing ~ 17 % (at 4500 A) to the overall flux. This is the first direct detection of a white dwarf in an intermediate polar system. The absence of significant Zeeman splitting indicates a magnetic field lower than 10 MG, confirming that, at least in some cases, intermediate polars have weaker fields than polars. Different possibilities are discussed to explain the substantial contribution of the white dwarf to the overall flux.

6 pages, 4 figures, 3 tables. accepted in Astronomy & Astrophysics

Cited by in corpus (14)

• 20-100 keV properties of cataclysmic variables detected in the INTEGRAL/IBIS survey
• INTEGRAL survey of the Cassiopeia region in hard X rays
• Magnetic Field Evolution in Accreting White Dwarfs
• Properties of the Galactic population of cataclysmic variables in hard X-rays
• Hard X-ray properties of magnetic cataclysmic variables
• X-ray and optical observations of 1RXS J154814.5-452845: a new intermediate polar with soft X-ray emission
• The X-ray emission of the Intermediate Polar V709 Cas
• X-ray Orbital Modulations in Intermediate Polars
• The long period Intermediate Polar 1RXSJ154814.5-452845
• INTEGRAL Broadband X-ray spectrum of the intermediate polar V709 Cas
• Influence of Compton scattering on the broad-band X-ray spectra of intermediate polars
• An extensive photometric study of the recently discovered intermediate polar V515 And (XSS J00564+4548)
• Analysis of the white--light flickering of the Intermediate Polar V709 Cas with wavelets and Hurst analysis
• Extensive photometry of the intermediate polar V1033 Cas (IGR J00234+6141)