Classification of Late-Type Stars in the Near Ultraviolet from Objective Prism Spectra.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Classification of Late-Type Stars in the Near Ultraviolet from Objective Prism Spectra. McCarthy, Martin F. ; Rubin, Vera C. Abstract Examination of the first plates obtained with the Vatican 25"/38.5" Schmidt and its 40 objective prism (O'Connell, Mitt. Astron. Ges. 100,1955) revealed a richness of ultraviolet features in G and K type stars and prompted a study of classification criteria in the region from 3400 to 3900 A. The prism is made of flint and was not especially designed for ultraviolet transmission: its dispersion at H~ is 250 A/mm and at 3700 A is 150 A/mm. Many blends used by previous investigators are resolved into separate lines at our dispersion. In the present study both eye estimates and microdensitometer tracings have been made. The spectra of stars classified in the LF 2 (McCuskey and Seyfert, Astrophys. J. 112, 90,1950) and LF4 (McCuskey, Astrophys. J. Suppl. 2, 75,1955) regions have been chosen as secondary standards. Fourteen Vatican plates and four from the Case collection were examined. Thirty-nine stars of spectral types G2 and G5 and luminosity classes III, IV, and V were studied. Between the H and K lines and the CN blend at 3585 A are 13 features, each of which has been investigated for use as a possible luminosity criterion. The excellence of Lindblad's criterion at 3883 A for the separation of giants and dwarfs is indicated. Eight low E.P. lines of Fe show variations in strength and sharpness from star to star. A strong feature a 3660 A is noted in certain giant stars. No new luminosity discriminants have been outstanding. Further work will include multiple exposures on standard MK stars. Stars from the catalogues of Keenan and Keller and Nancy Roman will be observed and the research will be extended to later spectral types. Publication: The Astronomical Journal Pub Date: September 1963 DOI: 10.1086/109099 Bibcode: 1963AJ.....68R.285M full text sources ADS |