Spectra and Colors of Early-Type Stars Near the North Galactic Pole.

Abstract

view Abstract Citations (74) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectra and Colors of Early-Type Stars Near the North Galactic Pole. Slettebak, Arne ; Bahner, Klaus ; Stock, Jürgen Abstract Slit spectrograms of 84 stars to a limiting magnitude of about 12 and of type F2 and earlier in a north galactic pole zone were taken with the Mount Wilson 60-inch and 100-inch telescopes in order to obtain spectral types, radial velocities, and axial-rotation velocity estimates. U, B, V observations of most of these stars were made with the McDonald 36-inch and 82-inch telescopes. The principal results are the following: (1) The majority of stars considered belong to the "older population I." The percentage of halo population II stars to the limiting magnitude of this study is small. (2) Sixteen new metallic-line stars were found. The relationship between the spectral classification parameters and the colors of these stars is discussed. (3) Considering only the normal population I stars, the estimated rotational velocities suggest that axial rotation may be less at high galactic latitudes than for stars of similar spectral type in the neighborhood of the sun. (4) The spectra of 10 of the stars considered show decided population II characteristics. These include hot subdwarfs, F- and G-type subdwarfs and horizontal-branch stars. Some of these have large radial velocities, but none shows azial rotational line broadening. The position of these and other stars on the two-color diagram is discussed. Publication: The Astrophysical Journal Pub Date: July 1961 DOI: 10.1086/147139 Bibcode: 1961ApJ...134..195S full text sources ADS | data products SIMBAD (116) GCPD (1)