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We present high speed photometric observations of 20 faint cataclysmic variables, selected from the Sloan Digital Sky Survey and Catalina catalogues. Measurements are given of 15 new directly measured orbital periods, including four…

Solar and Stellar Astrophysics · Physics 2015-06-03 Patrick A. Woudt , Brian Warner , Deanne de Bude , Sally Macfarlane , Matthew P. E. Schurch , Ewald Zietsman

We report the discovery of five very cool white dwarfs in the Sloan Digital Sky Survey (SDSS). Four are ultracool, exhibiting strong collision induced absorption (CIA) from molecular hydrogen and are similar in color to the three previously…

Ultraviolet observations using the Solar Blind Channel on the Hubble Space Telescope provide light curves and low resolution spectra of three pulsating white dwarfs in the cataclysmic variables SDSS013132.39-090122.3,…

We present two new GW Vir-type pulsating white dwarf stars, TIC\,0403800675 (WD\,J115727.68-280349.64) and TIC\,1989122424 (WD J211738.38-552801.18) discovered in the Transiting Exoplanet Survey Satellite (TESS) photometric data. For both…

Solar and Stellar Astrophysics · Physics 2022-04-20 Murat Uzundag , Alejandro H. Corsico , S. O. Kepler , Leandro G. Althaus , Klaus Werner , Nicole Reindl , Maja Vuckovic

Carbon stars and DZ white dwarfs are two types of rare objects in the Galaxy. In this paper, we have applied the label propagation algorithm to search for these two types of stars from Data Release Eight (DR8) of the Sloan Digital Sky…

Instrumentation and Methods for Astrophysics · Physics 2013-12-25 Jianmin Si , Ali Luo , Yinbi Li , Jiannan Zhang , Peng Wei , Yihong Wu , Fuchao Wu , Yongheng Zhao

We report the serendipitous discovery of the Sloan Digital Sky Survey star, SDSS J160043.6+074802.9 to be a very rapid pulsator. The variation is dominated by a frequency near 8380 microHz (period = 119.33 s) with a large amplitude (0.04…

We report the detection of periodic variations on the T_eff ~32 000 K DA white dwarf star HE 1017-1352. We obtained time series photometry using the 4.1 m SOAR telescope on three separate nights for a total of 16.8 h. From the frequency…

Solar and Stellar Astrophysics · Physics 2020-06-10 Alejandra D. Romero , L. Antunes Amaral , S. O. Kepler , L. Fraga , D. Kurtz , H. Shibahashi

We report on the identification of 22 new cool DO-type white dwarfs (WD) detected in Data Release 10 (DR10) of the Sloan Digital Sky Survey (SDSS). Among them, we found one more member of the so-called hot-wind DO WDs, which show ultrahigh…

Solar and Stellar Astrophysics · Physics 2014-12-10 N. Reindl , T. Rauch , K. Werner , S. O. Kepler , B. T. Gänsicke , N. P. Gentile Fusillo

We present the identification of 13 DB + dM binaries and 2 DC + dM binaries from the Sloan Digital Sky Survey (SDSS). Before the SDSS only 2 DB + dM binaries and 1 DC + dM binary were known. At least three, possibly 8, of the new DB + dM…

Beyond its goals related to the extragalactic universe, the Sloan Digital Sky Survey (SDSS) is an effective tool for identifying stellar objects with unusual spectral energy distributions. Here we report on the 53 new magnetic white dwarfs…

Astrophysics · Physics 2009-11-10 Gary D. Schmidt

We discovered two bright DO-type white dwarfs, GALEXJ053628.3+544854 (J0536+5448) and GALEX231128.0+292935(J2311+2929), which rank among the eight brightest DO-type white dwarfs known. Our non-LTE model atmosphere analysis reveals effective…

Solar and Stellar Astrophysics · Physics 2018-07-18 Nicole Reindl , Stephan Geier , Roy H. Østensen

We present photometry of nine cataclysmic variable stars identified by the Sloan Digital Sky Survey, aimed at measuring the orbital periods of these systems. Four of these objects show deep eclipses, from which we measure their orbital…

Solar and Stellar Astrophysics · Physics 2015-05-14 John Southworth , C. M. Copperwheat , B T Gansicke , S Pyrzas

We report the discovery of pulsations in the spectroscopic PG 1159 type pre-white dwarf SDSS J075415.12+085232.18. Analysis of the spectrum by Werner, Rauch and Kepler (2014) indicated Teff=120 000+/-10 000 K, log g=7.0+/-0.3, mass…

Solar and Stellar Astrophysics · Physics 2015-06-19 S. O. Kepler , Luciano Fraga , Don Earl Winget , Keaton Bell , Alejandro H. Corsico , Klaus Werner

During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low amplitude, multimode sdB pulsators with periods of the order…

SDSS J111215.82+111745.0 is the second pulsating extremely low-mass white dwarf discovered. Two short-period pulsations, 107.56 and 134.275 s, were detected on this star, which would be the first observed pressure mode ($p$-mode) pulsations…

Solar and Stellar Astrophysics · Physics 2023-02-08 Jie Su , Yan Li

We report the discovery of rapid periodic signals in the light curves of two cataclysmic variables with prominent white-dwarf components in their spectra, SDSS J1457+51 and BW Sculptoris. These stars therefore appear to be new members of…

We report the discovery of two new hot, hydrogen-rich subdwarfs (sdB) in close binary systems. The hot subdwarfs, GALEX J0321+4727 and GALEX J2349+3844, were selected from a joint optical-ultraviolet catalogue of hot sub-luminous stars…

Solar and Stellar Astrophysics · Physics 2015-05-19 A. Kawka , S. Vennes , P. Nemeth , M. Kraus , J. Kubat

We present a model atmosphere analysis of ten new DO white dwarfs and five new PG 1159 stars discovered in the Sloan Digital Sky Survey DR1, DR2 and DR3. This is a significant increase in the number of known DOs and PG 1159 stars. DO white…

Astrophysics · Physics 2007-05-23 S. D. Huegelmeyer , S. Dreizler , K. Werner , J. Krzesinski , A. Nitta , S. J. Kleinman

Periodically variable quasars have been suggested as close binary supermassive black holes. We present a systematic search for periodic light curves in 625 spectroscopically confirmed quasars with a median redshift of 1.8 in a 4.6 deg$^2$…

This paper completes the series of cataclysmic variables (CVs) identified from the Sloan Digital Sky Survey I/II. The coordinates, magnitudes and spectra of 33 CVs are presented. Among the 33 are eight systems known previous to SDSS (CT…