New Survey of the Variable Stars in the Small Magellanic Cloud

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS New Survey of the Variable Stars in the Small Magellanic Cloud Gaposchkin, Cecilia Payne Abstract Almost 1600 variable stars have been announced in the Small Magellanic Cloud, but although 969 of them were announced by Miss Leavitt over 50 years ago, they have never been systematically studied. We have begun the measurement of all these stars on all available Harvard plates, of which over 500 are generally available for each star. The measurements are being carried out by, or under the supervision of, Sergei Gaposchkin. Some of the measurements have been made by Kenneth Janes. The preliminary reductions are made by the writer, and Edward Gaposchkin, Chief of Computations at the Smithsonian Astrophysical Observatory, is programming the final reductions for the IBM 7090. The Small Cloud is being divided for study into about 80 regions of equal area. Results for six of these regions have been completed, as shown in the tabulation. Number of variable stars Number of Cepheids Known New Known New Total pedod period Total 73 10 83 24 40 64 In many cases the published periods have been improved. No special search for new variables was made; the new discoveries are stars that obtruded themselves on the observers. We may expect that the number of variables will be augmented by about 10% in this way during the investigation. The new periods are for stars that have hitherto been unstudied. In addition to the Cepheids, there are a number of eclipsing stars, both of known and new period, a few long-period and semiregular red variables, and a few stars that have hitherto defied analysis. However it is evident that the majority of the known variables are Cepheids. On the basis of the fact that 77 % of the stars studied at present are Cepheids, we may expect that there are about 1300 Cepheids in the Small Cloud twice the number now recognized. As the material accumulates, it will be applied to a redetermination of the period-luminosity curve, and to a study of the relationship between the brightness and other characteristics of the Cepheids in the Small Cloud. Publication: The Astronomical Journal Pub Date: June 1962 DOI: 10.1086/108718 Bibcode: 1962AJ.....67..279G full text sources ADS |