167 citations · 691 across the 25 of their papers we have counts for
12 papers · 1 filter
Discovery of 74 new bright ZZ Ceti stars in the first three years of TESS
A. D. Romero, S. O. Kepler, J. J. Hermes +17
We report the discovery of 74 new pulsating DA white dwarf stars, or ZZ Cetis, from the data obtained by the Transiting Exoplanet Survey Satellite (TESS) mission, from Sectors 1 to…
VVV-WIT-08: the giant star that blinked
Leigh C. Smith, Sergey E. Koposov, Philip W. Lucas +11
We report the serendipitous discovery of a late-type giant star that exhibited a smooth, eclipse-like drop in flux to a depth of 97 per cent. Minimum flux occurred in April 2012 an…
Rotational modulation and single g-mode pulsation in the B9pSi star HD174356?
Z. Mikulasek, E. Paunzen, S. Huemmerich +19
Chemically peculiar (CP) stars of the upper main sequence are characterised by specific anomalies in the photospheric abundances of some chemical elements. The group of CP2 stars,…
Pulsation in the white dwarf HE 1017-1352: confirmation of the class of hot DAV stars
Alejandra D. Romero, L. Antunes Amaral, S. O. Kepler +3
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 s…
The sdA problem - II. Photometric and Spectroscopic Follow-up
Ingrid Pelisoli, S. O. Kepler, D. Koester +3
Subdwarf A star (sdA) is a spectral classification given to objects showing H-rich spectra and sub-main sequence surface gravities, but effective temperature lower than the zero-ag…
Orbital parameters and evolutionary status of the highly peculiar binary system HD 66051
E. Paunzen, M. Fedurco, K. G. Helminiak +8
The spectroscopic binary system HD 66051 (V414 Pup) consists of a highly peculiar CP3 (HgMn) star and an A-type component. It also shows out-of-eclipse variability that is due to c…
New SX Phe variables in the globular cluster NGC 288
E. Martinazzi, S. O. Kepler, J. E. S. Costa +4
We report the discovery of two new variable stars in the metal-poor globular cluster NGC 288, found by means of time-series CCD photometry. We classified the new variables as SX Ph…
Discovery of a new PG1159 (GW Vir) Pulsator
S. O. Kepler, Luciano Fraga, Don Earl Winget +3
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) indic…
Asteroseismological study of massive ZZ Ceti stars with fully evolutionary models
A. D. Romero, S. O. Kepler, A. H. Córsico +2
We present the first asteroseismological study for 42 massive ZZ Ceti stars based on a large set of fully evolutionary carbonoxygen core DA white dwarf models characterized by a…
Magnetic White Dwarf Stars in the Sloan Digital Sky Survey
S. O. Kepler, Ingrid Pelisoli, Stefan Jordan +10
To obtain a better statistics on the occurrence of magnetism among white dwarfs, we searched the spectra of the hydrogen atmosphere white dwarf stars (DAs) in the Data Release 7 of…
He II 4686 in eta Carinae: collapse of the wind-wind collision region during periastron passage
M. Teodoro, A. Damineli, J. I. Arias +23
The periodic spectroscopic events in eta Carinae are now well established and occur near the periastron passage of two massive stars in a very eccentric orbit. Several mechanisms h…
GALEX and Optical Observations of GW Librae During the Long Decline from Superoutburst
Eric Bullock, Paula Szkody, Anjum S. Mukadam +14
The prototype of accreting, pulsating white dwarfs (GW Lib) underwent a large amplitude dwarf nova outburst in 2007. We used ultraviolet data from GALEX and ground-based optical ph…