[vsnet-campaign-v4641sgr 164] V4641 Sgr: Minor outburst

[Makoto Uemura <uemura@kusastro.kyoto-u.ac.jp>]

V4641 Sgr: Minor outburst

    We have detected a minor outburst of V4641 Sgr on August 5.  
During our ~6 hours time-series observation, the object was 
brightening with a rate of 1.2 mag/d, reached the maximum at 
about Rc~13.1mag, and then, rapidly fading with a rate of 4.8 mag/d.  
These brightening and fading rates are too large to be explained 
by ordinary ellipoidal modulations.  

    No large second-order flare was detected within a time 
resolution of 12-13s (exposure time = 10s).  But, we can see 
some hints of short-term (a few minutes) modulations with amplitudes 
of 0.1-0.2 mag.  

    The activity of V4641 Sgr is still unpredictable, and long 
monitoring is encouraged.

Regards,
Makoto Uemura

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp