A Study of the Scale Height of the Thin Galactic Disk in the Solar Neighborhood

An attempt is made to determine the scale height of the thin Galactic disk in the solar neighborhood using various stellar samples from the accurate astrometric data of the Hipparcos satellite. Using the Tycho color indices and considering the completeness of the samples, several samples were selected from the main sequence and the horizontal branch. Based on two rather complete samples, it is found that the scale height of the Galactic disk defined by the O-B type main sequence stars is 103.1 ± 3.0 pc and the Sun is located at height of 15.2 ± 7.3 pc above its mean plane; while the scale height of the Galactic disk defined by the horizontal branch stars is 144.0 the ±10.0 pc and the Sun is located at height 3.5 ± 5.4 pc above the mean plane. Owing to the incompleteness of observational samples, it is not possible to use the main sequence stars of spectral types A, F, G, K and M to make a reliable determination of the scale height.