Light Curve Morphology Study of UW CrB -- Evidence for a 5 d Superorbital Period

Abstract

Since its discovery in 1990, UW CrB (also known as MS1603+2600) has remained a peculiar source without firm classification. Our current understanding is that it is an Accretion Disc Corona (ADC) low mass X-ray binary. In this paper we present results from our photometric campaign dedicated to studying the changing morphology of the optical light curves. We find that the optical light curves show remarkable evidence for strongly evolving light curve shapes. In addition we find that these changes show a modulation at a period of $\sim$ 5 days. We interpret these changes as either due to strong periodic accretion disc warping or other geometrical changes due to disc precession at a period of 5 days. Finally, we have detected 11 new optical bursts, the phase distribution of which supports the idea of a vertically extended asymmetric accretion disc.

arXiv comment9 pages, 6 figures, accepted for publication in MNRAS

References in corpus (5)

• XMM-Newton observations of UW CrB -- detection of X-ray bursts and evidence for accretion disc evolution
• Discovery of Optical Bursts from MS1603.6+2600 = UW CrB
• 3D eclipse mapping in AM Herculis systems - `Genetically modified fireflies'
• ASCA Observation of MS 1603.6+2600 (=UW Coronae Borealis): a Dipping Low-Mass X-ray Binary in the Outer Halo?
• MS 1603.6+2600: an Accretion Disc Corona source?

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