An investigation of galactic structure in a region of Cygnus.

Abstract

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An investigation of galactic structure in a region of Cygnus. Annear, Paul Abstract This investigation was carried out with the ~-inch Burrell Schmidt-type telescope at the Warner and Swasey Observatory. It is a part of a general program dealing with the luminosity function in the plane of the galaxy in process at that observatory. The field investigated has its center about three degrees south of P Cygni, and includes parts of the Cygnus Cloud, Great Rift, and a prominent parabolic area of obscuration. It also includes part of an area where a well-known clustering of B stars exists. The spectral types and photographic magnitudes of all (1281) stars to 12.0 photographic magnitude were obtained within an area of 12.5 square degrees. Photo-red magnitudes were obtained for all stars of spectral type Ao and earlier (6o8), and for I I I stars of later spectral types. Star-counts were made to photographic magnitude 17.6 as an aid in determining absorption features over the plate. In spite of the fact that the region involves absorption which is definitely non-uniform, it was divided into two areas approximately homogeneous in absorption. In one area, which includes part of the Great Rift, the absorption begins at about 500 parsecs and increases rapidly to about two and one-half magnitudes at 1500 parsecs. In the other area, it increases more slowly to about two magnitudes at 3000 parsecs. Using these absorptions, a density analysis was made for various spectral groups in each area. The B-type stars show clustering tendencies at various distances, whereas the other spectral groups in general show a rapid decrease in density with increasing distance from the sun. A comparison with the standard luminosity function reveals an excess of luminous stars (M between -4 and $1) in this region, and a deficiency of less luminous stars (M between I and Y4), a result in agreement with conclusions reached in two other fields included in this general program. B urrell Observatory, Baldwin- Wallace College, Berea, Ohio. Publication: The Astronomical Journal Pub Date: 1949 DOI: 10.1086/106298 Bibcode: 1949AJ.....54R.181A full text sources ADS |