Carnegie Institution for Science | 2016 May 17
[img3="Color-magnitude diagrams for all bright stars within 1,000 light-years of the Sun as determined by Mt. Wilson astronomers in 1935. (Left) Diagram without the subgiants, in which it is difficult to connect the two clear populations. (Right) Diagram with the subgiants discovered by Walter Adams et al. The subgiants form a connective tissue between the sequences that inspired Allan Sandage and his colleagues to advance the theory of stellar evolution by exploring the physical properties of these stars relative to the other sequences."]https://carnegiescience.edu/sites/carne ... 99x512.jpg[/img3][hr][/hr]Carnegie’s Allan Sandage, who died in 2010, was a tremendously influential figure in the field of astronomy. His final paper, published posthumously, focuses on unraveling a surprising historical mystery related to one of his own seminal discoveries.
While preparing a centennial history of the Carnegie Observatories in the early 2000s, Sandage came across an unpublished 1944 exchange between two prominent astronomers that piqued his interest. The conversation seemed to predate by a decade Sandage’s own work on stellar evolution in the mid-1950s. ...
it turns out that physicist and astronomer George Gamow and astronomer Walter Adams exchanged a letter that included a hand-drawn figure from Gamow that predated Sandage’s illustration of stellar evolution by 10 years.
This letter was influenced by a more-than-20-years-in-the-making catalog of more than 4,000 stellar classifications and distances produced at then-Carnegie’s Mount Wilson Observatory in 1935. (This catalog remained the largest in existence until the 1990s.) It turns out that the catalog identified 90 subgiants, although the classification was effectively ignored by scholarly circles, due to criticisms that the catalog was biased and the fear that any new findings it introduced were likely fictitious.
Sandage, Beaton, and Majewski pored through the records, comparing all 90 of the subgiant measurements from the 30s to modern measurements and finding them very accurate and precise. ...
Comparison of Hipparcos Trigonometric and Mount Wilson Spectroscopic Parallaxes for 90
Subgiants that Defined the Class in 1935 - Allan Sandage, Rachael L. Beaton, Steven R. Majewski
- Publications of the ASP 128(964):064202 (2016 June) DOI: 10.1088/1538-3873/128/964/064202
arXiv.org > astro-ph > arXiv:1511.05930 > 18 Nov 2015
