Related papers: Amplitude Modulation in the ZZ Ceti Star GD 244
We present the results of a comparative period search on different time-scales and modelling of the ZZ Ceti (DAV) star GD 154. We determined six frequencies as normal modes and four rotational doublets around the ones having the largest…
We observed the ZZ Ceti star GD 154 over a whole season at the mountain station of Konkoly Observatory. Our long time base allowed to detect the sign of rotational triplets around the independent modes. To check whether these can be real…
We present the analysis of one week of single-site high-speed CCD photometric observations of the cool ZZ Ceti star HS 0507+0434B. Ten independent frequencies are detected in the star's light variations: one singlet and three nearly-equally…
The internal structures of pulsating white dwarfs can be explored only with asteroseismology. Time series photometric observations were made for the pulsating DA white dwarf (ZZ Ceti star) WD~0246+326 during 9 nights in 2014 with a bi-site…
The ZZ Ceti star GD 1212 was detected to have 19 independent modes from the two-wheel-controlled Kepler Spacecraft in 2014. By asymptotic analysis, we identify most of pulsation modes. We find out two set of complete triplets, and four sets…
We summarize our findings on three cool ZZ Ceti type pulsating white dwarfs. We determined eight independent modes in HS 0733+4119, of which seven are new findings. For GD 154, we detected two new eigenmodes, and the recurrence of the…
With typical periods of order 10 minutes, the pulsation signatures of ZZ Ceti variables (pulsating hydrogen-atmosphere white dwarf stars) are severely undersampled by long-cadence (29.42 minutes per exposure) K2 observations. Nyquist…
G 207-9 and LP 133-144 are two rarely observed ZZ Ceti stars located in the middle and close to the blue edge of the ZZ Ceti instability domain, respectively. We aimed to observe them at least during one observing season at Konkoly…
The pulsating DA white dwarfs (ZZ Ceti stars) are $g$-mode non-radial pulsators. Asteroseismology provides strong constraints on their global parameters and internal structure. Since all the DA white dwarfs falling in the ZZ Ceti…
We present the results on period search and modeling of the cool DAV star KUV 02464+3239. Our observations resolved the multiperiodic pulsational behaviour of the star. In agreement with its position near the red edge of the DAV instability…
We present our preliminary results on the asteroseismological investigations of the ZZ Ceti star GD 244. We used literature values of the effective temperature and surface gravity and utilized the White Dwarf Evolution Code of Bischoff-Kim,…
The nature of period and amplitude changes in nonradial pulsators is presently unknown. It is therefore important to examine the correlations between these changes in stars with a large number of simultaneously excited pulsation modes.…
The nature of the observed amplitude variability of several modes in the Delta Scuti star FG Vir is examined. In this star, three frequencies show strong amplitude and phase variations. In the power spectrum, these frequencies also show up…
Pulsators on and near the main sequence show period and amplitude changes that are too large to be the product of stellar evolution. The multiperiodic Delta Scuti stars are well suited to study these changes. This requires a very large…
We present the Kepler light curve of KIC 4552982, the first ZZ Ceti (hydrogen-atmosphere pulsating white dwarf star) discovered in the Kepler field of view. Our data span more than 1.5 years with a 86% duty cycle, making it the longest…
We present the results of our detailed light curve analysis of the ZZ Ceti star HS 1625+1231. We collected photometric time series data at Konkoly Observatory on 14 nights, and performed Fourier analysis of these data sets. We detected 11…
KUV 11370+4222 is a ZZ Ceti star discovered in 1996, which has not been observed since then. We performed observations for KUV 11370+4222 in 2010 January. From the Fourier transform spectrum of the light curves, ten independent modes are…
We present the results of a search for amplitude modulation of pulsation mode frequencies in 983 $\delta$ Sct stars, which have effective temperatures between 6400 $\leq T_{\rm eff} \leq$ 10 000 K in the Kepler Input Catalogue and were…
Context. Knowing the rotation rates and masses of white dwarf stars is an important step towards characterising the angular momentum transport mechanism in their progenitors, and coupling the cores of red giants to their envelopes. However,…
In most Delta Scuti stars, the measured period changes are considerably larger than those expected from stellar evolution. In order to study these period and amplitude changes, a few selected stars are measured photometrically for hundreds…