Related papers: The Everchanging Pulsating White Dwarf GD358
Pulsation frequencies reveal the interior structures of white dwarf stars, shedding light on the properties of these compact objects that represent the final evolutionary stage of most stars. Two-minute cadence photometry from TESS will…
We report on analysis of 308.3 hrs of high speed photometry targeting the pulsating DA white dwarf EC14012-1446. The data were acquired with the Whole Earth Telescope (WET) during the 2008 international observing run XCOV26. The Fourier…
We present analysis of a new pulsating helium-atmosphere (DB) white dwarf, EPIC~228782059, discovered from 55.1~days of {\em K2} photometry. The long duration, high quality light curves reveal 11 independent dipole and quadruple modes, from…
We report the discovery of the second and third pulsating extremely low mass white dwarfs (WDs), SDSS J111215.82+111745.0 (hereafter J1112) and SDSS J151826.68+065813.2 (hereafter J1518). Both have masses < 0.25 Msun and effective…
We present follow-up time-series photometric observations that confirm and extend the results of the significant discovery made by Barlow et al.(2008) that the Hot DQ white dwarfs SDSS J220029.08-074121.5 and SDSS J234843.30-094245.3 are…
The pulsating DA white dwarfs are the coolest degenerate stars that undergo self-driven oscillations. Understanding their interior structure will help to understand the previous evolution of the star. To this end, we report the analysis of…
PG 1159-035, a pre-white dwarf with T=140000 K, is the prototype of the PG1159 spectroscopic class and the DOV pulsating class. Changes in the star cause variations in its oscillation periods. The measurement of temporal change in the…
Nonradial pulsations in the primary white dwarfs of cataclysmic variables can now potentially allow us to explore the stellar interior of these accretors using stellar seismology. In this context, we conducted a multi-site campaign on the…
Since pulsating subdwarf B (sdBV or EC14026) stars were first discovered (Kilkenny et al, 1997), observational efforts have tried to realize their potential for constraining the interior physics of extreme horizontal branch (EHB) stars.…
GD356 is a magnetic white dwarf (B = 13MG) that uniquely displays weak resolved Zeeman triplets of Halpha and Hbeta in emission. As such, GD356 may be the only known white dwarf with some kind of chromosphere, although accretion from the…
The Kepler spacecraft provides new opportunities to search for long term frequency and amplitude modulations of oscillation modes in pulsating stars. We ana- lyzed nearly two years of uninterrupted data obtained with this instrument on the…
Photometric variability in massive, magnetic white dwarfs (WDs) on the timescales of less than a few hours is oft interpreted as being due to magnetic spots on the surface of a rotating star. Increasingly, numbers of these short period…
Since pulsating subdwarf B (sdBV or EC14026) stars were first discovered (Kilkenny et al, 1997), observational efforts have tried to realize their potential for constraining the interior physics of extreme horizontal branch (EHB) stars.…
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.…
We aimed at collecting all known white dwarf pulsators with hydrogen-dominated atmospheres and list their main photometric and atmospheric parameters together with their pulsation periods and amplitudes observed at different epochs. For…
We present a preliminary analysis of time series photometry on the pulsating subdwarf B star PG1336-018 acquired as part of two Whole Earth Telescope runs. PG1336-018 is a multi-mode pulsator with at least 15 periods centered around 175…
Extensive photometric multisite campaigns of the Delta Scuti variable FG Vir are presented. For the years 2003 and 2004, 926 hours of photometry at the millimag precision level were obtained. The combinations with earlier campaigns lead to…
Time-resolved observations of brown dwarfs' rotational modulations provide powerful insights into the properties of condensate clouds in ultra-cool atmospheres. Multi-wavelength light curves reveal cloud vertical structures, condensate…
Previous studies of GD 244 revealed seven pulsation frequencies (two doublets and three single periods) in the light variations of the star. The data obtained at McDonald Observatory between 2003 and 2006, and our additional measurements in…
We present a follow-up analysis of the unique magnetic luminosity-variable carbon-atmosphere white dwarf SDSS J142625.71+575218.3. This includes the results of some 106.4 h of integrated light photometry which have revealed, among other…