Variations in UV extinction in galactic associations and perpendicular to the galactic plane.
Abstract
For about 1200 O - B4 stars observed by ANS, normalized UV extinction parameters, E(bump)/E(B-V) and E(1550 - 1800)/E(B-V), have been calculated together with the distance from the galactic plane, z. A slight correlation of UV extinction parameters with |z| appears: at high |z| low values of E(bump)/E(B-V) and high values of E(1550 - 1800)/E(B-V) are more frequent. Shock waves and/or radiation fields may be responsible for this effect. The same parameters have been studied in 30 OB associations. Association-to-association variations of UV extinction are confirmed, which are not well correlated with galactic longitude. The open cluster Tr 37 is found to exhibit an exceptional behaviour.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 1987
- Bibcode:
- 1987A&A...185..291K
- Keywords:
-
- B Stars;
- Interstellar Extinction;
- Milky Way Galaxy;
- O Stars;
- Star Clusters;
- Ultraviolet Spectra;
- Data Bases;
- Open Clusters;
- Periodic Variations;
- Radiation Distribution;
- Astrophysics