Accretion Disc Evolution in DW Ursae Majoris: A Photometric Study ⋆

摘要: Received ;accepted Abstract. We present an analysis of CCD photometric observations the eclipsing novalike cataclysmic variable DW UMa obtained in two different luminosity states: high and intermediate. The star pr esents eclipses with very depth:∼ 1.2 mag and∼ 3.4 intermediate state. Eclipse mapping reveals that this difference is almost entirely due to changes accretion disc radius: from∼ 0.5RL1 state to∼ 0.75RL1 (RL1 distance from white dwarf first Lagrangian point). In state, entire eclipsed while its outer part remains visible. also find ce ntral intensity nearly same states it increase radius re sponsible for final rise 1999 /2000 low profile rather flat sugges t a possible explanation. discuss effect using more realistic limb-darkening law on temperatures inferred eclipse experiments. Periodogram data "positive superhumps" period 0. d 1455 2002 1461 2003, accord results Patterson et al. However, we cannot confirm quasi-peri odic oscillations reported by these authors. obtain updated orbital ephemeris UMa: Tmin(HJD) = 2446229.00687(9) + 136606527(3)E.