87 citations · 349 across the 9 of their papers we have counts for
9 papers
Low mass variable stars in the globular cluster NGC 6397
E. Martinazzi, S. O. Kepler, J. E. S. Costa
We have conducted a photometric survey of the globular cluster NGC 6397 in a search for variable stars. We obtained ~11h of time-resolved photometric images with one ne European So…
A comparative analysis of the observed white dwarf cooling sequence from globular clusters
Fabíola Campos, P. Bergeron, A. D. Romero +8
We report our study of features at the observed red end of the white dwarf cooling sequences for three Galactic globular clusters: NGC\,6397, 47\,Tucanae and M\,4. We use deep colo…
Probing Mass Segregation in NGC 6397
E. Martinazzi, A. Pieres, S. O. Kepler +3
In this study, we present a detailed study of mass segregation in the globular clister NGC 6397. First, we carry out a photometric analysis of projected ESO-VLT data (between 1 and…
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…
The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035
J. E. S. Costa, S. O. Kepler
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 oscillat…
The pulsation modes of the pre-white dwarf PG 1159-035
J. E. S. Costa, S. O. Kepler, D. E. Winget +74
PG 1159-035, a pre-white dwarf with T_eff=140,000 K, is the prototype of both two classes: the PG1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-0…