Galactic structure towards the North Galactic Pole based on an analysis of UBV star-count data

Abstract

view Abstract Citations (87) References (65) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Galactic Structure Towards the North Galactic Pole Based on an Analysis of UBV Star-Count Data Yoshii, Y. ; Ishida, K. ; Stobie, R. S. Abstract The UBV star-count data for a sample of about 18,000 stars brighter than V = 19 mag over 21.46 square degrees towards the North Galactic Pole are presented. The star-count data are distributed in the two-dimensional planes of apparent V magnitude to B - V and to U - B color. A Galaxy model which imposes the most stringent constraints on a possible intermediate component between disk and spheroid is constructed. In view of the coupling among the model parameters, a least-squares method is adopted to obtain the best Galaxy model in which the model distributions of number density and metallicity reproduce the observed star counts. An intermediate component is identified of which the local normalization factor is 2 percent of the disk stars and the scale height is 1.0 kpc. This component contributes about 20 percent of the observed number of stars for V = 15-17. The metallicity gradient is found to be d(Fe/H)/dz = -0.5 + or 0.1/kpc for z of 2 kpc or less in logarithmic scale by assuming the solar abundance in the Galactic plane. Publication: The Astronomical Journal Pub Date: February 1987 DOI: 10.1086/114317 Bibcode: 1987AJ.....93..323Y Keywords: Astronomical Models; Galactic Structure; Milky Way Galaxy; Star Distribution; Ubv Spectra; Color-Magnitude Diagram; Metallicity; Stellar Luminosity; Stellar Spectrophotometry; Astrophysics; GALAXIES: STRUCTURE; STARS: STELLAR STATISTICS full text sources ADS | data products SIMBAD (5) NED (1)