[vsnet-obs 42877] V1149 Ori

["Sebastian Otero" <varsao@fullzero.com.ar>]

> *  Eclipse I. Hipparcos' period (6.236 d.) can be confirmed and refined to
> 6.2369 d. This is a cromospherically active star, so EA/RS type.

Well, forget about that.
I shouldn't jump to conclusions that easily...
Tonight's observation was also 6.9, so the star is faint again when it
shouldn't be...
I had reported two eclipses this week based on this faint state.. Of course
they agreed in phase with the "eclipses" but any other observation in the
middle would have been "an eclipse" too.
I searched for photometric data on this star and I found:
UBV(RI)c photometry of active stars. IX (Cutispoto+, 2001)

With this in hand I could fold a rather complete lightcurve that shows a
marked periodicity.
There are 10 clear maxima and 7 minima. I found an average 27.15 days period
for the minima and 27.83 day period for the maxima. They give a mean period
of 27.49 d.

According to the reference this is a system made up of a K2/3III and a F8V
star.
The amplitude and mean magnitude of each cycle is variable.
Calibrating Hipparcos data with the simultaneous V photometry, gives a total
range for the period March 1990, february 1994 of V= 6.718 - 6.972.
There is also a fainter measurement in the GCPD so the total range measured
is 6.72-7.01V

The star is slightly redder at minimum but the color variation in B-V
doesn't exceed 0.05 mag. (1.12-1.17)

The clasification is not EA/RS then. I think that these are pulsations from
the orange giant.
Or could they be great spots in the giant? Isn't it a too late type for this
RS activity?

Regards,
Sebastian.



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