■ [supernova] Type IIP SNe 2008ij and 2008in have just come in the rapidly decreasing luminosity phase
figure(a) : Light curve of SN 2008ij
figure(b) : Light curve of SN 2008in
We show the light curves of two Type IIP supernovae (SNe IIP) 2008ij and 2008in in figure(a) and figure(b), respectively. The "TRI" and "HOW" mean that the data was obtained using TRISPEC and HOWPol, respectively. The two SNe has begun to rapidly decrease the luminosity, and the color of two SNe rapidly become red. The outer hydrogen layer of SNe IIP expanded and became optically thin. The spectral might show that the Balmer series of hydrogen lines weaken.
■ [dwarf nova] J1028-08 : humps with a very short period, confirmed
Due to the detection of possible superhumps with a quite short period (0.0381~d), the object is suspected to be a rare object, such as V485 Cen and EI Psc, or AM CVn stars (double-white dwarf system) (vsnet-alert 11149).
We performed time-series photometric observations of J1028-08 with KANATA last night (2 Apr). We confirmed the humps whose period is roughly consistent with the reported one. We found that the V-J color is quite blue (V-J~-0.6). The V-J color is usually between -0.2 and 0.2 in normal dwarf novae in superoutburst. In our past observations, CR Boo, an AM CVn star, exhibited a similar color during its superoutburst.
Although the S/N of our J-band data is low, phase-averaged light curves suggest that the hump amplitude is larger in V-band than that in J-band. The temperature of the hump component is probably higher than that of an underlying stationary component.