KZ Hya time keeping
Observations: 25, 27 April, 18, 19 May 2004
28 June 2005
Three pulses are observed for this SX Phe pulsating star. They
are 29 mn late from the 29 yr old GCVS ephemeris.
KZ Hya is a pulsating star of the SX Phe type with a period of 85 mn.
According to the GCVS one has the ephemeris for the pulses:
T0 = 2442516.15836 (13 April 1975)
P0 = 0.0595104212
KZ Hya was observed with a 203 mm f/6.3 SC telescope, a SBIG ST7-E camera
(KAF401E CCD) and a Rc filter. 170 images were obtained. The comparison star
is Tycho 6638-00764 with an assumed Rc magnitude of 9.8. The check star is
Tycho 6638-00842 with a measured Rc magnitude of 9.63 and a standard deviation
An example of a light curve:
Red: KZ Hya, green: the check star shifted by +1 mag. The error bars
are the +/- 1 sigma statistical uncertainty. KZ Hya was very low over
the horizon and the atmosphere unsteady.
All the light curves are here.
When folded with the period P0, the observations give the phase plot:
Comparison with the ephemeris
Three pulses are observed at: 121.412, 123.376, 144.382 (HJD - 2453000).
The uncertainty is about +/-0.0015. They are 29 mn late from the 29-yr old GCVS ephemeris.
It would be interesting to know if the star is slowing down or if it experienced
some "glitch" in a recent past. More observations would tell.
Telescope and camera configuration.
Software and computer configuration.