[vsnet-alert 14351] (fwd) TOCP J08461690+3115554, 21 Mar 2012 (de Miguel)

[Taichi Kato]

TOCP J08461690+3115554, 21 Mar 2012 (de Miguel)

   Forwarded message:

  3 orbital eclipses on top of a noisy light curve (my estimate is  
that the mean magnitude of this target is 18.6 ! which is 1 mag
fainter than Masi's estimate yesterday).  Porb=2.1950(8) hr

Regards,
Enrique

===

Comments:      Faintest target I've ever followed along a time series.
               The light curve is much noisier than the one G. Masi
               obtained yesterday, even though the observing conditions
               have been exceptionally good. The reason is that the
               target is about mag 18.6 ! This is estimated by comparing
               my comp (C) and check (K) stars with respect to 
               GSC 2484-01575, which is reported as 13.72 V (of course,
               a value not to be taken too literally). 
               With respect to this star, C is estimated as 15.4 and
               K as 15.6 (these two stars are just flanking the target
               star, about 30-45 arcsec from the target). The mean
               out-of-eclipse magnitude relative to C is 3.2, and
               3.0 relative to K, which gives an estimate of 18.6 ....
               Real V mag (considering my transformation equations)
               must be ~18.4-18.5 V. This is too faint for me ....

                Despite the above, I've been able to capture 3 eclipses.
               Timing these 3 along with the one from Masi's light curve,
 
                HJD_min = 2456007.3383(2) + 0.09146(3) E

                and therefore an orbital period of 2.1950(8) hr.
                The corresponding errors are just those arising from
                the linear regression, but should be larger considering
                the noise when determining the minima.

                There are clear signs of relatively large amplitude
                superhumps. Psh is estimated (ANOVA) as 0.0959(19) d,
                which gives eps = 0.049.