■ [Extragalactic nova] M33 2010-07a : rebrightening ?
We update the light curve of extragalactic nova M33 2010-07a. The light curves of I and R-bands show the sudden rebrightening. The rebrightening just after the maximum light is also seen in that of Galactic very fast nova V2498 Cyg. Such a phenomena may be caused by the strong magnetic filed of the surface of the white dwarf. We will continue the photometric observations of M33 2010-07a.
■ [Extragalactic nova] M33 2010-07a
We have started the photometric observations of extragalactic nova M33 2010-07a. This object was discovered of 17.1 mag in M33 on Jul. by K. Nishiyama and F. Kabashima (CBET 2374). The light curve exhibits the very fast decline, which indicates that the progenitor mass of this object is much higher than that of average classical novae.
■ [Symbiotic Nova] Spectroscopy of V407 Cyg : update
We newly obtained the low-resolution spectrum of V407 Cyg at Jul. 18 UT. The spectrum shows the strong red continuum at longer than 8000 A. The red component is contributed from the red companion star in the system of V407 Cyg. It suggests that the photosphere almost shrinkage and the binary component come to be seen. The emissions of Pachen series and OI 8446 are not seen. The emission of H-alpha also weakened.
We newly obtained the spectrum of the peculiar nova V1280 Sco on Jul. 18. The spectral profile of the spectrum is roughly consistent with those obtained on Mar. 12 and Apr. 17. We confirm that the H-alpha profile exhibits the slight growth of the blue-side component of emission line.
■ [dwarf nova] J2138+26: almost at quiescence
The WZ Sge-type dwarf nova, J2138+26, is now almost at quiescent level (CBET 2274). We found two noteworthy points in color variations: First, the V-J color remains constant in the last 10 days of the superoutburst. This suggests that the temperature of the outermost region of an accretion disk was almost constant at that period of time. Second, we could not see a very red phase just after the outburst, which was observed in GW Lib, a very similar source to J2138+26. In conjunction with the superhump evolution (e.g. vsnet-alert 11993), the lack of the very red phase implies that J2138+26 is not a very extreme WZ Sge-type object, but rather similar to ordinary SU UMa stars.