6 papers
Two new ZZ Ceti pulsators from the HS and HE surveys
R. Silvotti, B. Voss, I. Bruni +4
We report the detection of nonradial g-mode oscillations in the DA white dwarfs HS1039+4112 (B=15.9) and HE1429-0343 (B=15.8) from time-series photometry made at the Loiano 1.5 m t…
BeppoSAX observations of AM Herculis in intermediate and high states
G. Matt, D. de Martino, B. T. Gaensicke +5
Temporal and spectral analyses from BeppoSAX observations of AM Her performed during both an intermediate and a high state are presented and discussed. Optical observations taken a…
Time-resolved HST and IUE UV spectroscopy of the Intermediate Polar FO Aqr
D. de Martino, R. Silvotti, D. A. H Buckley +4
Time resolved spectroscopy of the Intermediate Polar FO Aqr reveals the presence of multiple periodicities in the UV range. A strong orbital modulation dominates both continuum and…
The photometric behaviour of the peculiar PG1159 star HS2324+3944 at high frequency resolution
R. Silvotti, S. Dreizler, G. Handler +1
We present the results from 135 hours of nearly continuous time series photometry on the ``hybrid'' (H-rich) PG1159 variable star HS2324+3944, obtained in August-September 1997. Th…
HS2324+3944: discovery of non-radial pulsations in a hydrogen-rich PG1159 star
R. Silvotti
HS\,2324+3944 is a peculiar PG\,1159 star, with a high amount of H in its atmosphere (Dreizler et al. 1995). Its location in the -- plane is well inside…
Search for new pulsating O VI central stars of planetary nebulae
R. Silvotti, C. Bartolini, L. Stanghellini
A photoelectric monitoring program has been applied, during the last four years, to five central stars of planetary nebulae (PNNs) with strong O\,VI 3811--34 Å\hspace{0.1mm} em…