[vsnet-campaign-dn 4969] GW Lib: short-term modulations on 18 and 19 Apr.

[uemuram at hiroshima-u.ac.jp]

GW Lib: short-term modulations on 18 and 19 Apr.

  We observed GW Lib with TRISPEC/KANATA on 18 and 19 Apr., 
and obtained V-, J-, and Ks-band light curves.

  http://kanatatmp.blogspot.com/search/label/GW%20Lib

The object is gradually fading. The fading speed was initially about 
0.3 mag/day, but getting smaller on 18 and 19 Apr. The fading speed is 
now 0.15, 0.10, and 0.12 mag/day in the V-, J-, and Ks-bands, 
respectively. The change of the fadig speed may indicate the evolution 
of the effect of the tidal instability. Ordinary superhumps might 
be detected in the next couple of days.

On 18 Apr., characteristics of short-term modulations look different 
in V- , J-, and Ks-band light curves. The J-band light curve was, 
in particular, interesting in the point that it shows periodic 
modulations. Our preliminary period analysis yielded a period of 
0.0526(6) d, probably a period of early humps. The hump profiles 
are complicated, but sometimes have double-peak profile.

The light curves on 19 Apr., in contrast to those on 18 Apr., 
show similar short-term modulations in the V-, J-, and Ks-bands. 
The modulations are most prominent in the J-band. A weak periodicy 
around 0.05 d was found in our period analysis of the J-band light 
curve.

Follow-up observations are encouraged.

Regards,
Makoto Uemura and Akira Arai
on behalf of the KANATA team