Galactic Structure Toward the Carina Tangent

Abstract

ABSTRACTThis investigation presents a photometric study of the Galactic structure toward the Carina arm tangent. The field is located between 280° and 286° Galactic longitude and -4° to 4° Galactic latitude. All currently available uvbyβ data are used to obtain homogeneous color excesses and distances for more than 260 stars of spectral types O to G. We present revised distances and average extinction for the open clusters and cluster candidates NGC 3293, NGC 3114, Lodén 46, and Lodén 112. The cluster candidate Lodén 112 appears to be a very compact group at a true distance modulus of 11.06 ± 0.11(s.e.) (), which is significantly closer than previous estimates. We found other OB stars at that same distance and, based on their proper motions, suggest a new OB association at coordinates 282° < l < 285° and -2° < b < 2°. Utilizing BV photometry and spectral classification of the known O-type stars in the very young open cluster Wd 2, we provide a new distance estimate of 14.13 ± 0.16 (s.e.) (), in excellent agreement with recent distance determinations to the giant molecular structures in this direction. We also discuss a possible connection between the H ii region RCW 45 and the highly reddened B+ star CPD -553036 and provide a revised distance for the luminous blue variable HR Car.