Distribution of early type stars and dusty matter in the direction of the star cluster NGC 2175

Abstract

The distribution of 120 O-B9-A2 stars and of the interstellar dust in the direction of the star clusters NGC 2175 and NGC 2175s (the complex S252) is studied in terms of V, (B-V), and (U-B) data. Ten star groups (associations) are found at distances of 410, 720, 1000, 1500, 2200, 3100, 4000, 5200, 7000, and 8100 pc. Three of these, at distances of 410, 720, and 1000 pc, are type B associations. The remaining seven are OB associations. They are designated as Gem B 0.41, Gem B 0.72, Gem B 1.0, Gem OB 1.5, Gem OB 2.2, Gem OB 3.1, Gem OB 4.0, Gem OB 5.2, Gem OB 7.0, and Gem OB 8.1. The V absorption (A_V) for stars No.2, 18, 20, 23, 24, 26, 40, 41, 47, 69, 87, 88, 90, 95, 100 and 109 is estimated to be 2^m.78,4^m.72, 2^m.69, 3^m.33, 2^m.61, 2^m.86, 4^m.67, 6^m.21, 3^m.14, 3^m.92, 2^m.69, 3^m.04, 5^m.95, 5^m.95, 3^m.20 and 5^m.66, respectively. For most of these stars the absorption lies between 0^m.5 and 2^m.5. This large absorption may be caused by circumstellar absorption. The dust in the associations Gem B 0.41 and Gem B 0.72 is distributed nonuniformly. There is no dust in the space between the associations. Essentially there is no dust inside those groups (associations) which lie at distances greater than 1 kpc.