Suppression of X-rays during an optical outburst of the helium dwarf nova KL Dra

Abstract

KL Dra is a helium accreting AM CVn binary system with an orbital period close to 25 mins. Approximately every 60 days there is a 4 mag optical outburst lasting ~10 days. We present the most sensitive X-ray observations made of an AM CVn system during an outburst cycle. A series of eight observations were made using XMM-Newton which started shortly after the onset of an optical outburst. We find that X-rays are suppressed during the optical outburst. There is some evidence for a spectral evolution of the X-ray spectrum during the course of the outburst. A periodic modulation is seen in the UV data at three epochs -- this is a signature of the binary orbital or the super-hump period. The temperature of the X-ray emitting plasma is cooler compared to dwarf novae, which may suggest a wind is the origin of a significant fraction of the X-ray flux.

Accepted by MNRAS

References in corpus (5)

• V344 Lyrae: A Touchstone SU UMa Cataclysmic Variable in the Kepler Field
• Models of AM CVn star outbursts
• The long term optical behaviour of helium accreting AM CVn binaries
• Serendipitous Kepler observations of a background dwarf nova of SU UMa type
• Spectral Mapping of the Intermediate Polar DQ Herculis

Cited by in corpus (7)

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• Swift X-ray and UV Observations of SDSS J141118.31+481257.6 During its First Ever Recorded Superoutburst
• The Fast Evolving, Tremendous and Blue Superoutburst in ASASSN-21au Reveals a Dichotomy in the Outbursts of Long-period AM CVns
• Broad Observational Perspectives Achieved by the Accreting White Dwarf Sciences in the XMM-Newton and Chandra Eras
• Peculiarities of the Accretion Flow in the System HL CMa
• TCP J07222683$+$6220548: a new AM CVn type system with infrequent outbursts