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We present the analysis of time-resolved spectroscopy of the pulsating sdB star PG1605+072. From our main observing run of 16 nights we have detected velocity variations at 5 frequencies that correspond to those found in photometry. Based…

Astrophysics · Physics 2009-11-07 S. J. O'Toole , T. R. Bedding , H. Kjeldsen , T. H. Dall , D. Stello

Here, we present the 1UVA catalog of time variable ultraviolet (UV) sources. We describe a new analysis pipeline, the VAriable Source Clustering Analysis (VASCA). We apply the pipeline to 10 years of data from the GALaxy Evolution eXplorer…

Astrophysics of Galaxies · Physics 2024-07-31 Rolf Buehler , Julian Schliwinski

The Blue Large-Amplitude Pulsators (BLAPs) constitute a new class of pulsating stars. They are hot stars with effective temperatures of ~30 000 K and surface gravities of log g ~ 4.9, that pulsate with periods in the range 20-40 min. Until…

Solar and Stellar Astrophysics · Physics 2018-04-11 Alejandra D. Romero , A. H. Córsico , L. G. Althaus , I. Pelisoli , S. O. Kepler

We present for the first time phase-resolved UV spectroscopy of an Of?p star, namely, HD 191612. The observations were acquired with the Space Telescope Imaging Spectrograph (STIS) on-board the Hubble Space Telescope (HST). We report the…

Solar and Stellar Astrophysics · Physics 2015-06-15 W. L. F. Marcolino , J. -C. Bouret , J. O. Sundqvist , N. R. Walborn , A. W. Fullerton , I. D. Howarth , G. A. Wade , A. ud-Doula

The survey phase of the Kepler Mission includes a number of hot subdwarf B (sdB) stars to search for nonradial pulsations. We present our analysis of two sdB stars that are found to be g-mode pulsators of the V1093 Her class. These two…

We present an atmospheric retrieval analysis of HST/WFC3/G141 spectroscopic phase curve observations of two brown dwarfs, WD-0137B and EPIC-2122B, in ultra-short period orbits around white dwarf hosts. These systems are analogous to hot and…

Solar and Stellar Astrophysics · Physics 2024-04-26 Joshua D. Lothringer , Yifan Zhou , Daniel Apai , Xianyu Tan , Vivien Parmentier , Sarah L. Casewell

V391 Peg (HS2201+2610) is an extreme horizontal branch subdwarf B (sdB) star, it is an hybrid pulsator showing p- and g-mode oscillations, and hosts a 3.2/sini M_Jup planet at an orbital distance of about 1.7 AU. In order to improve the…

Solar and Stellar Astrophysics · Physics 2015-05-19 Roberto Silvotti , Suzanna Randall , Vik S. Dhillon , Tom R. Marsh , Chris D. Savoury , Sonja Schuh , Gilles Fontaine , Pierre Brassard

DBV stars are pulsating white dwarfs with atmospheres rich in He. Asteroseismology of DBV stars can provide valuable clues about the origin, structure and evolution of hydrogen-deficient white dwarfs, and may allow to study neutrino and…

Solar and Stellar Astrophysics · Physics 2015-06-03 Alejandro H. Córsico , Leandro G. Althaus , Marcelo M. Miller Bertolami , Agnès Bischoff-Kim

We combine photometric and spectroscopic data on twelve modes excited in FG Vir to determine their spherical harmonic degrees, $\ell$, and to obtain constraints on the star model. The effective temperature consistent with the mean colours…

MOST observations and model analysis of the Herbig Ae star HD 34282 (V1366 Ori) reveal {\delta}-Scuti pulsations. 22 frequencies are observed, 10 of which confirm those previously identified by Amado et al. (2006), and 12 of which are newly…

Brown dwarfs in close-in orbits around white dwarfs offer an excellent opportunity to investigate properties of fast-rotating, tidally-locked, and highly-irradiated atmospheres. We present Hubble Space Telescope Wide Field Camera 3 G141…

Observations of rotational modulations of brown dwarfs and giant exoplanets allow the characterization of condensate cloud properties. As of now rotational spectral modulations have only been seen in three L-type brown dwarfs. We report…

Multi-wavelength time-resolved observations of rotationally modulated variability from brown dwarfs and giant exoplanets are the most effective method for constraining their heterogeneous atmospheric structures. In a companion paper (Bowler…

Earth and Planetary Astrophysics · Physics 2022-01-14 Yifan Zhou , Brendan P. Bowler , Caroline V. Morley , Dániel Apai , Tiffany Kataria , Marta L. Bryan , Björn Benneke

We present results from high speed photometry of a further thirteen faint cataclysmic variables. V356 Aql (Nova Aql 1936) shows flare-like outbursts with recurrence time scales ~ 3000 s, but no coherent periodicities. Aqr1 is an…

Astrophysics · Physics 2009-11-10 Patrick A. Woudt , Brian Warner , Magaretha L. Pretorius

We present photometry and spectroscopy for 27 pulsating hydrogen-atmosphere white dwarfs (DAVs, a.k.a. ZZ Ceti stars) observed by the Kepler space telescope up to K2 Campaign 8, an extensive compilation of observations with unprecedented…

We explore changes in the adiabatic low-order g-mode pulsation periods of 0.526, 0.560, and 0.729 M$_\odot$ carbon-oxygen white dwarf models with helium-dominated envelopes due to the presence, absence, and enhancement of $^{22}$Ne in the…

Pulsating subdwarf B (sdB) stars oscillate in short-period p-modes or long-period g-modes. HS0702+6043 (DW Lyn) is one of a few objects to show characteristics of both types and is hence classified as hybrid pulsator. It is one of our…

Solar and Stellar Astrophysics · Physics 2015-05-13 R. Lutz , S. Schuh , R. Silvotti , R. Kruspe , S. Dreizler

We observed the young ($\sim 1700$ yrs) pulsar PSR B0540-69 in the near-ultraviolet (UV) for the first time with the Space Telescope Imaging Spectrograph (STIS) aboard the {\em Hubble Space Telescope}. Imaging observations with the NUV- and…

High Energy Astrophysical Phenomena · Physics 2019-02-13 R. P. Mignani , A. Shearer , A. de Luca , F. E. Marshall , L. Guillemot , D. A. Smith , B. Rudak , L. Zampieri , C. Barbieri , G. Naletto , C. Gouiffes , G. Kanbach

Many brown dwarfs are on ultra-short period and tidally-locked orbits around white dwarf hosts. Because of these small orbital separations, the brown dwarfs are irradiated at levels similar to hot Jupiters. Yet, they are easier to observe…

Solar and Stellar Astrophysics · Physics 2021-12-22 Ben W. P. Lew , Dániel Apai , Yifan Zhou , Mark Marley , L. C. Mayorga , Xianyu Tan , Vivien Parmentier , Sarah Casewell , Siyi Xu

To date, pulsational variability has been measured from nearly 70 DBVs and 500 DAVs, with only a fraction of these having been the subjects of asteroseismic analysis. One way to approach white dwarf asteroseismology is forward modeling,…

Solar and Stellar Astrophysics · Physics 2023-08-09 Agnes Bischoff-Kim
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