A New Catalogue of Hα Emission Objects in the Southern Hemisphere.

Abstract

view Abstract Citations (4) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A New Catalogue of Hα Emission Objects in the Southern Hemisphere. Wray, James D. Abstract Henize at the Lamont Hussey Observatory have been searched for Ha emission objects, S stars, and carbon stars. A previous search by Henize of medium-exposure plates covering the entire southern hemisphere to +10.5 m~ at a dispersion of 450 A/mm at Ha has yielded 1100 stars tentatively classified as early-type Ha emission stars. The recent search by the author of long-exposure plates covering the southern Milky Way from 240~100 galactic longitude to + 13.0 m~ has revealed an additional 800 probable early-type emission stars, and a few new objects of type P, C, and S. Coordinates (a, ~) accurate to H*~1511 p.e. have been computed for all obj ects found on the long exposure plates by means of a 12 constant-plate reduction theory modified to account for tangential distortion introduced by the objective prism. All standard stars were of spectral type A0, providing a well-defined absorption line at Ha for measurement. Plate measures were obtained on a fully digitized Mann 621 comparator with punched card output. Use of a digital x,y plotter for identification of comparison stars, evaluation of plate reduction residuals, and measure data confirmation greatly facilitated the data reduction. A preliminary analysis of the surface distribution of southern hemisphere early-type emission stars reveals the strong concentration of the galactic plane and the irregular distribution in longitude similar in nature to that found in the northern hemisphere by Merrill. The relatively high surface concentration in the Carina-Crux region previously examined by Bok is fully confirmed by this survey. Publication: The Astronomical Journal Pub Date: 1966 DOI: 10.1086/110160 Bibcode: 1966AJ.....71S.403W full text sources ADS |