COMMUNICATIONS / MITTEILUNGEN

L.G. Balázs , M. Paparó, I. Tóth

Distribution of Stars of Spectral Types of F7 and Earlier in a Field around NGC 7686

No. 85
Budapest, 1985

Abstract

A statistical study was performed on 993 stars of spectral type F7 and earlier in 19.5 sq. deg. field centered on NGC 7686 down to limiting magnitude of 12.5. The observational material was obtained with Konkoly Observatory's 60/90/180 cm Schmidt telescope. The stars were classified utilizing small scale spectra (580 A/mm at H-gamma) and photographic UBV colours were measured. The interstellar absorption in this area was determined to be AV= 1.2 mag. and the space densities in the spectral groups of B8-A1, A2-A3, A4-A7, A8-F2 and F3-F7 were obtained using the matrix method of Dolan. Our empirical space distributions were compared with an exponential model, with Camm's models, with Bahcall's model and with that of Wolley and Stewart. The best fit was obtained by an isothermal model and this fitting enabled us to estimate the total mass density near the Sun resulting 0.104 M_sun/pc³ using the B8-A1 group and 0.159 M_sun/pc³using the A type stars. These figures do not differ from the observed total mass density on the one sigma significance level.

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