We present results of new photometric observations of the contact binary system astrobj{HI Pup} as well as the radial velocity curve of the system. Time series multicolour photometry was obtained at the South African Astronomical Observatory (SAAO) u
sing the 1-m Cassegrain Telescope. We applied a simultaneous solution to the $BVRI$ light and radial velocity curves in order to determine the physical parameters of the system. From an analysis of the new multicolour data, the physical parameters were found to be $M_1=1.22M_{odot}$, $M_2=0.23M_{odot}$, $R_1=1.44R_{odot}$, $R_2=0.67R_{odot}$, $L_1=3.3L_{odot}$, $L_2=0.7L_{odot}$. Our solution confirms that HI Pup has a typical A--type W UMa binary system characteristics.
We present results of an asteroseismic study on the $gamma$ Dor type {it Kepler} target KIC,6462033. {it Kepler} photometry is used to derive the frequency content and principal modes. High-dispersion ground-based spectroscopy is also carried out in
order to determine the atmospheric parameters and projected rotational velocity. From an analysis of the {it Kepler} long cadence time series, we find that the light curve of KIC,6462033 is dominated by three modes with frequencies $f_{1}$=0.92527, $f_{2}$=2.03656 and $f_{3}$=1.42972 d$^{-1}$ as well as we detect more than a few hundreds of combination terms. However, two other independent frequencies appear to have lower amplitudes in addition to these three dominant terms. No significant peaks are detected in the region $>$ 5 d$^{-1}$. We therefore confirm that KIC,6462033 pulsates in the frequency range of $gamma$ Dor type variables, and a future study will allow us to investigate modal behaviour in this star.
We present new photometric observations of eclipsing binary systems V1241 Tau and GQ Dra. We use the following methodology: Initially, WD code is applied to the light curves, in order to determine the photometric elements of the systems. Then the res
iduals are analysed using Fourier Transformation techniques. The results show that one frequency can be barely attributed to the residual light variation of V1241 Tau, while there is no evidence of pulsation on the light curve of GQ Dra.
We present the first preliminary results on the analysis of ground-based time series of the {gamma} Dor star KIC 6462033 (TYC 3144-646-1, V = 10.83, P = 0.69686 d) as well as Kepler photometry in order to study pulsational behaviour in this star.{gam
ma} Dor variables, which exhibit g-mode pulsations, are promising asteroseismic targets to understand their rich complexity of pulsational characteristics in detail. In order to achieve this goal, intensive and numerous multicolour and high resolution spectroscopic observations are also required, to complete space-based data aimed at the determination of their physical parameters.
We present results of a multi-site photometric campaign on the high-amplitude $delta$,Scuti star KIC,6382916 in the {it Kepler} field. The star was observed over a 85-d interval at five different sites in North America and Europe during 2011. {it Kep
ler} photometry and ground-based multicolour light curves of KIC,6382916 are used to investigate the pulsational content and to identify the principal modes. High-dispersion spectroscopy was also obtained in order to derive the stellar parameters and projected rotational velocity. From an analysis of the {it Kepler} time series, three independent frequencies and a few hundred combination frequencies are found. The light curve is dominated by two modes with frequencies $f_{1}$= 4.9107 and $f_{2}$= 6.4314,d$^{-1}$. The third mode with $f_{3}$= 8.0350,d$^{-1}$ has a much lower amplitude. We attempt mode identification by examining the amplitude ratios and phase differences in different wavebands from multicolour photometry and comparing them to calculations for different spherical harmonic degree, $l$. We find that the theoretical models for $f_1$ and $f_2$ are in a best agreement with the observations and lead to value of l = 1 modes, but the mode identification of $f_3$ is uncertain due to its low amplitude. Non-adiabatic pulsation models show that frequencies below 6,d$^{-1}$ are stable, which means that the low frequency of $f_1$ cannot be reproduced. This is further confirmation that current models predict a narrower pulsation frequency range than actually observed.
We report on a multi-site photometric campaign on the high-amplitude $delta$ Scuti star V2367 Cyg in order to determine the pulsation modes. We also used high-dispersion spectroscopy to estimate the stellar parameters and projected rotational velocit
y. Time series multicolour photometry was obtained during a 98-d interval from five different sites. These data were used together with model atmospheres and non-adiabatic pulsation models to identify the spherical harmonic degree of the three independent frequencies of highest amplitude as well as the first two harmonics of the dominant mode. This was accomplished by matching the observed relative light amplitudes and phases in different wavebands with those computed by the models. In general, our results support the assumed mode identifications in a previous analysis of Kepler data.
