[vsnet-campaign-polar 94] Two-Period Variability of the Intermediate Polar EX Hya

[Ivan Andronov]

Two-Period Variability of the Intermediate Polar EX Hya

The star was observed using the telescopes of the Tzec Maun observatory. 3 hourly runs were obtained in alternatively changing Bessel filters V and R.
Totally 72 points were obtaned. As the star exhibits two types of variability - orbital and spin one.

The most recent ephemeris for the spin is

T_E=2437699.89165+E*(0.046546484+E*(-7.34e-13+E*2.16e-19))
(Mauche et al., 2009, http://www.konkoly.hu/cgi-bin/IBVS?5876 ).
We have computed a "new" epoch for the cycle number 376913, which is closest to the sample mean of times of our observations   T_mean  =2455243.85646:

T_E=2455243.77387
and a new value of the period
0.046546484+376913*(-7.34e-13*2+376913*2.16e-19*3)=0.0465460227

The ephemeris for the orbital variations is

TDB(eclipse)=2437699.94179 + 0.068233846 E