Related papers: Photometric White Dwarf Rotation
Some of the white dwarfs exhibit among the strongest magnetic fields in the universe. Many of these degenerate magnetic stars are also rotating very slowly. Among these objects, Grw+70$^\circ$\,8247, with its century-long suspected rotation…
We present a comprehensive photometric, spectroscopic, and polarimetric study of the intermediate polar (IP) 1RXS J080114.6-462324, using observations from the South African Astronomical Observatory (SAAO) 1.0-m and 1.9-m telescopes and the…
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…
Over the past few years monitoring programs have shown ultra cool dwarfs (UCDs) to be photometrically variable. Of the 60 sources monitored in the field and some 120 monitored in clusters, about 40% show variability in both cases. For mid…
We present our findings on the spectral analysis of seven magnetic white dwarfs that were presumed to be double degenerates. We obtained time-resolved spectroscopy at the Gemini Observatory to look for evidence of binarity or fast rotation.…
The possible existence of warm ($T_{\rm eff}\sim19\,000$ K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti stars, was predicted in theoretical studies more than 30 yr ago. However, to date, no pulsating warm DA WD has been…
The TESS mission delivers time-series photometry for millions of stars across the sky, offering a probe into stellar astrophysics, including rotation, on a population scale. However, light curve systematics related to the satellite's…
White dwarfs, the final evolutionary stage of the vast majority of stars, serve as critical tools for cosmochronology, studies of planetary system evolution, and laboratories for non-standard physics, including exotic cooling channels and…
We present a preliminary analysis of the cool pulsating white dwarf GD 1212, enabled by more than 11.5 days of space-based photometry obtained during an engineering test of the two-reaction-wheel-controlled Kepler spacecraft. We detect at…
While brown dwarfs show similarities with stars in their early life, their spin evolution is much more akin to that of planets. We have used lightcurves from the K2 mission to measure new rotation periods for 18 young brown dwarfs in the…
We monitored the light variations of 22 weak-line T Tauri stars (WTTS) discovered among the X-ray sources in the field of the Taurus-Auriga cloud. The photometric variability of 12 out of these WTTS samples is confirmed. They are all proved…
Brown dwarfs were recently found to display rotational modulations, commonly attributed to cloud cover of varying thickness, possibly modulated by planetary-scale waves. However, the long-term, continuous, high-precision monitoring data to…
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…
Pulsation modes have recently been observed in a handful of white dwarf (WD) primaries of cataclysmic variables, allowing an interesting new probe into the structure of accreting WD's. We briefly discuss the seismology of these objects, how…
We present 13 years of pulsation timing measurements of the DBV white dwarf EC 2005-5234. Each of the four O-C diagrams mimic the sinusoidal behavior typically attributed to a planet + WD system. However, the amplitude and phase of the O-C…
Accreting magnetic white dwarfs offer an opportunity to understand the interplay between spin-up and spin-down torques in binary systems. Monitoring of the white dwarf spin may reveal whether the white dwarf spin is currently in a state of…
We report the discovery of pulsations in the extremely low mass (ELM), likely helium-core white dwarf GD 278 via ground- and space-based photometry. GD 278 was observed by the Transiting Exoplanet Survey Satellite (TESS) in Sector 18 at a…
The majority of stars both host planetary systems and evolve into a white dwarf (WD). To understand their post-main-sequence (PMS) planetary system evolution, we present a search for transiting/eclipsing planets and other Substellar Bodies…
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 present rotation periods for thousands of active stars in the Kepler field derived from Q3 data. In most cases a second period close to the rotation period was detected, which we interpreted as surface differential rotation (DR). Active…