Fundamental parameters and new variables of the galactic open cluster NGC 7128

Citation
Z. Balog et al., Fundamental parameters and new variables of the galactic open cluster NGC 7128, M NOT R AST, 323(4), 2001, pp. 872-886
Citations number
49
Categorie Soggetti
Space Sciences
Journal title
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
ISSN journal
00358711 → ACNP
Volume
323
Issue
4
Year of publication
2001
Pages
872 - 886
Database
ISI
SICI code
0035-8711(20010601)323:4<872:FPANVO>2.0.ZU;2-K
Abstract
CCD photometry in Johnson UBV and Stromgren uvby systems and medium-resolut ion spectroscopy of the galactic open cluster NGC 7128 are presented. Spect ral types of the brightest 12 stars in the cluster field were determined ba sed on equivalent widths of the Hac and the HeI 6678-Angstrom line. The spe ctroscopic observations also revealed two obvious and one probable Be-type stars showing H alpha emission. The analysis of the photometric diagrams ga ve a colour excess of E(B - V) = 1.03 +/- 0.06 mag, a distance modulus DM = 13.0 +/- 0.2 mag and an age above 10 Myr. Time-resolved photometric observ ations obtained on one night resulted in the detection of short time-scale light variations of seven new and three already known variable stars in the cluster field.