V4641 Sgr: remarkable flaring state!!
We (SSO) have just sended to VSnet , time-series photometry on July 7 (UT)
Although the observation was slightly affect by the
clouds, V4641 Sgr shows *dramatic* repeated flare-like brightenings
by 0.5 mag. The typical e-folding decay time of the flares was only
a few minutes. The rise usually took 30 s to 2 min. A 0.3 mag fading
within 40 s(!) was also observed in one of these flares. Such a dramatic
activity reminds us of the repeated flaring state of the microquasar
GRS 1915+105 observed in X-rays.
Such dramatic variation of any variable star was totally
unprecedented and unexpected.
Run Time Serie 20020707
Run Time Serie 20020713
The data show a monotonic trend, and no
apparent short-term or flare-like
beightenings were recorded. The object may have calmed down,
Astrophysics abstract astro-ph/0208146