arXiv subjects

B. Csák

Publications and source records attributed to B. Csák.

22 records · Page 2Linked to original sources

arXiv2007

Radial velocities of five globular clusters obtained with AAOmega

Using the recently commissioned multi-object spectrograph AAOmega on the 3.9m AAT we have obtained medium-resolution near-infrared spectra for 10,500 stars in and around five southern globular clusters. The targets were 47 Tuc, M12, M30, M55 and NGC 288. We have measured radial velocities to +/- 1 km/s with the cross correlation method and estimated metallicity, effective temperature, surface gra vity and rotational velocity for each star by fitting synthetic model spectra. An analysis of the velocity maps and velocity dispersion of member stars revealed systemic rotation in four of the target clusters.

astro-ph↗

arXiv2007

Pulsation and orbit of AU Pegasi

AU Pegasi is a pulsating star in a spectroscopic binary system with an orbital period of 53.26 days. Between 1960 and 1990 an extremely rapid period increase was observed in the value of the pulsation period, but in the last 15 years the observation show that the period set in 2.411 days. Fourier analysis of photometric data obtained during the ASAS project and those taken at the Piszkesteto Mountain Station of the Konkoly Observatory during 1994-2005 indicate that AU Pegasi is pulsating in two modes simultaneously, and the ratio of the frequencies of the two modes is 0.706, a value common for double-mode classical Cepheids. A careful analysis of other photometric observations obtained during the era of the strong period increase also revealed existence of a second mode. This may suggest that this star is not a Type II Cepheid, despite its galactic position.

astro-ph↗

arXiv2005

A comprehensive survey of variable stars in the globular cluster NGC 362

We present the first results of our variability survey for the globular cluster NGC 362. We found numerous variable stars in the field including 23 RR Lyr stars, 4 eclipsing binaries and 5 other pulsating stars. Four of the RR Lyr ae stars are located behind the cluster, possibly in the farthest extensions of the SMC.

astro-ph↗

arXiv2005

CCD photometry of 23 minor planets

We present CCD photometric observations of 23 main-belt asteroids, of which 8 have never been observed before thus the data of these objects are the first in the literature. The majority showed well detectable light variations, exceeding 0.1 mag. We have determined synodic periods for 756 Lilliana (9.36h), 1270 Datura (3.4h), 1400 Tirela (13.36h), 1503 Kuopio (9.98h), 3682 Welther (3.59h), 7505 Furushu (4.14h) and 11436 1969 QR (2.6h), while uncertain period estimates were possible for 469 Argentina (12.3h), 546 Herodias (10.4h) and 1026 Ingrid (5.3h). The shape of the lightcurves of 3682 Welther changed on a short time-scale and showed dimmings that might be attributed to eclipses in a binary system. For the remaining objects, only lower limits of the periods and amplitudes were concluded.

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