The galactic distribution of interstellar absorption as determined from the Celescope catalog of ultraviolet stellar observations and a new catalog of UBV, H-beta photoelectric observations.
Abstract
New UBV data for 2846 stars and Hfl photometry for 2099 stars are presented; all stars had previously been observed in the rocket ultraviolet in project Celescope, and ultraviolet magnitudes for them at U2 or U3 are available. The data are combined in an investigation of the ultraviolet interstellar extinction law, with emphasis placed on finding systematic variations in that law as functions of galactic longitude and distance. Our data confirm the previous finding that the ultraviolet extinction law is more variable in U3 (Ae = 1590 A) than in U2 (Ae = 2180 A), and that the U3 extinction is greatest for directions of view along spiral arms. In addition, the interstellar medium appears to be more homogeneous in some directions (e.g., toward Crux) and relatively inhomogeneous in others (Cygnus, Puppis). While our data show little evidence for a distance dependence of extinction in most directions, we do find a significant decrease in ultraviolet extinction at U2 and U3 relative to longer wavelengths over the galactic longitude interval 270 < 1 < 3600. Subject headings: interstellar: matter - photometry - ultraviolet: general
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- February 1976
- DOI:
- 10.1086/190359
- Bibcode:
- 1976ApJS...30...97D
- Keywords:
-
- Galactic Structure;
- H Beta Line;
- Interstellar Extinction;
- Star Distribution;
- Ubv Spectra;
- Ultraviolet Absorption;
- Astronomical Catalogs;
- Astronomical Photometry;
- Celescopes;
- Electrophotometry;
- Milky Way Galaxy;
- Stellar Spectrophotometry;
- Astronomy