Astronomers in 1944 he developed a classification of stars-subgiants.
Scientists Allan Sandidge, Steven Majewski, Rachael Beaton from the USA solved a century of astronomical mystery. They showed that their colleague George Gamow and Walter Adams in 1944 he developed a classification of stars-subgiants that Sandidge first introduced in the mid 1950-ies. Devoted to this work published in the journal Publications of the Astronomical Society of the Pacific, briefly about it it is reported on the website of the Carnegie institution in Washington (USA).
Gamow and Adams were in correspondence in 1944. In one of the letters was given the diagram of Hertzsprung — Russell disposed thereon subgiants. It allows you to classify stars according to their physical characteristics and to predict their evolution over time. Gamow and Adams was first depicted on it subgiant — group of stars, which are slightly heavier than the Sun and which ended hydrogen fuel.
As shown by studies of Sandidge and his colleagues, Gamow and Adams correctly pointed out the place of subgiants in the diagram. To do this, astronomers used data directory of the Observatory of mount Wilson, which by 1935 there were about 90 subgiants.
Earlier it was believed that the first position of these stars on the diagram indicated Sandigi, and the fact that other scientists have done it before him for 10 years, awakened his interest in archival investigation, begun in 2000-ies.
According to Sandidge, conclusions, Gamow and Adams were not seen because the position of subgiants on the main sequence (where the stars are, the fuel for thermonuclear reactions in which hydrogen is) diagram the Hertzsprung — Russell then was unable to describe with current models of stellar evolution. Work Sandidge and his colleagues in the mid 1950-ies has allowed to show that subgiant are a natural stage of evolution of main sequence stars.
