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(1992 Nov. 23)
I am at Ouda and observing the X-ray nova GRO J0422+32.
The two nights' observations have been sucessful. The resultant
light curve show clear superhump structure (characteristic steeper rise
and slower decline). Two distinct maxima have been obtained on
Nov. 22, at 22.472 and 22.730 UT. The amplitudes of the humps are
0.17 mag. in V. (The system is currently at about V = 14.0, 1.5 mag.
fainter then the optical maximum.) The light curve on the preceding
(Nov. 21) night is probably affected by a large flare ocurring
at 21.870 UT, but also show hump structures at 21.578 and 21.700 UT,
and suggestion of a bright maximum before 21.46 UT (start of the
observation). If the interval of two maxima on Nov. 22 is adopted,
the corresponding maximum is likely the one at 21.700 UT and the one
ocurring 21.578 UT seems to be a secondary maximum, just as observed in
SU UMa stars. The period obtained from these maxima is 0.257 days,
similar to that in V616 Mon (=A0620-00).
Because this value does not agree the periods suggested in IAU
circulars (4.96hr by C. Chevalier and S. A. Ilovaisky, IAUC 5644;
negative confirmation by T. Mazeh, E. M. Leibowitz, S. Hemar, and
H. Mendelson, IAUC 5650), I will continue the observation and confirm
the existence of the period.
Regards,
Taichi Kato
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
