The field of Lacerta OB1

Abstract

AbstractWe present a new analysis of the Galactic structure in the field of Lacerta. The investigation uses precise uvbyβ photometry and the recalculated Hipparcos parallaxes to provide an improved homogeneous distance scale to the main stellar groups in the field. The OB association Lac OB1 (Lac OB1b) is reliably identified as a very compact young group at an average distance of 520 ± 80 pc. The characteristics of the older Lac OB1a group and the open cluster NGC 7243 are extensively studied based on photometric diagrams and the inferred distances. A good agreement between the photometry-derived distances and the recalculated Hipparcos parallaxes is found for the Lac OB1 group, but in general discrepancies still exist for this particular field.