MBCAA Observatory

RV Cet: a Blazhko pulsating starObserved: 26 sessions in 20092011Michel Bonnardeau

20092010 season 
18 Nov, BV 20 Nov, BV 26 Nov, BV 2 Jan, BV 11 Jan, BV 13 Jan, BV 17 Jan, BV 18 Jan, BV 21 Jan, BV 

Totals  9 sessions 284 V 214 B 

20102011 season 
31 Aug, BV 1 Sep, V 3 Sep, BV 11 Sep, V 28 Oct, V 5 Nov, V 13 Nov, BV(2x6 only) 5 Feb, V 7 Feb, B(a few)V 

Totals  9 sessions 738 V 57 B 

20112012 season 
29 Sep, BV 30 Sep, V 25 Nov, V 26 Nov, V 27 Nov, V 25 Dec, V 27 Dec, BV 28 Dec, V 

Totals  8 sessions 1342 V 37 B 

Totals  26 sessions 2364 V 308 B 
For the differential photometry, the comparison star is GSC 528100670
with the magnitudes V=11.991 and B=12.515 (these magnitudes are computed
from the CMC14 r' magnitude and the 2MASS magnitudes using the transformations
of Bilir et al (2008) and of Smith et al (2002)). The check star is GSC
528100661 and is observed as having V=12.484+/0.024+/0.034 and B=13.053+/0.024+/0.029,
where the first +/ is the average 1sigma statistical uncertainty and
the second one is the standard deviation.
Session 26 Nov 2011: the comparison star is GSC 528100386
with V=13.118 and B=14.156; this does not introduce any significant offset.
An example of light curves:
Green: with the V filter, Blue: with the B filter.
The error bars are the 1sigma statistical uncertainties.
The pulsation is analyzed the following way:
Maxima are observed at: 834.52, 892.475, 924.275, 443.608, 498.504 HJD
2,455,000. They are not separed by an exact multiple of P because the
maxima swing with the Blazhko phase: a maximum is a little early when
the amplitude is high, and a little late when the amplitude is low. For
the phase plots below I adopt the ephemeris t(n) = T+P*n with:
T = 2,455,924.275
The resulting phase plots for the V magnitudes:
The 5 different colors correspond to the 5 groups of data each with
the same Blazhko phase.
The Blazhko phase origin is arbitrary. One group with a small pulsation
phase range is not shown.
From these observations, the Blazhko period is:
P_{B} = 123 +/ 13 days.
A pulsation phase plot of the B magnitudes, along the V magnitudes measured
at the same time:
Blue: the B magnitudes, Green: the V ones. The effect of the Blazhko
modulation can be seen.
A pulsation phase plot of the BV color:
Bilir S., Ak S., Karaali S., CabreraLavers A., Chonis T.S., Gaskell C.M. (2008) MNRAS 384 1178.
Clube S.V.M., Evans D.S., Jones D.H.P. (1969) Mem RAS 72 101.
Smith J.A., Tucker D.L., Kent S. et al (2002) AJ 123 2121.
Wils P., Lloyd C., Bernhard K. (2006) MNRAS 368 175.
Telescope and camera configuration.
Computer and software configuration.
Pulsating stars and the links therein.









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