UBV photographic photometry and objective-prism spectral classifications have been used to study the distribution of stars and interstellar reddening in the direction l = 245(DEGREES), b = 0(DEGREES) in the constellation Puppis. Spectrophotometry of a sample of (TURN)3300 B5 to M5 stars in a 7.75 square degree region to V (TURN) 12.5 reveals that interstellar absorption in this direction sets in at r (TURN) 400 pc, and rises steadily to A(,v) (TURN) 1('('m))7 at r (TURN) 8.8 kpc. The spatial distributions of various spectral groups are consistent in number and structure with those in other Galactic plane fields; the A2-A5 stars exhibit a density maximum at r (TURN) 1.2 kpc which may be associated with the bridge between the local and Carina spiral features, and the G-K giants appear more populous in this direction than at other Galactic longitudes. UBV photographic photometry of CTIO 4-metre plates to V (TURN) 15 over a field of (TURN)0.4 square degrees, and to V (TURN) 20.5 over a field of (TURN)0.02 square degrees has yielded a list of over 500 candidate faint (15 (LESSTHEQ) V (LESSTHEQ) 21) blue stars (06 < Sp < B5). The distribution of these stars as determined from the Q-method suggests a constant density to Galactocentric radius 20 kpc.
- Pub Date:
- Physics: Astronomy and Astrophysics