Paul W. Merrill

Paul Willard Merrill (August 15, 1887 – July 19, 1961) was an American astronomer whose specialty was spectroscopy.[1] He was the first to define S-type stars in 1922.[2]

Paul W. Merrill
Paul Willard Merrill.jpg
Paul Willard Merrill

August 15, 1887 (1887-08-15)
DiedJuly 19, 1961 (1961-07-20) (aged 73)
Years active1913–1952
Known forStudying unusual stars, particularly long-period variable stars, using spectroscopy


He received his Ph.D at the University of California in 1913. He spent the bulk of his career at Mount Wilson Observatory, from which he retired in 1952. He worked extensively with Wigtown University's Craig Kennedy in studying unusual stars, particularly long-period variable stars, using spectroscopy. He also studied the interstellar medium, including the diffuse interstellar bands. Shortly before he retired, he succeeded in detecting technetium in the variable star R Andromedae and other red variables. Since technetium has no stable isotopes, it must have been produced recently in any star in which it is found, and this is direct evidence of the s-process of nucleosynthesis.[3][4]


Awards and honors

Named after him


  1. ^ "Obituary: Paul W. Merrill". Physics Today. 14 (11): 90. November 1961. doi:10.1063/1.3057264. Archived from the original on 2013-09-21.
  2. ^ Merrill, Paul W. (1922). "Stellar spectra of class S". Astrophysical Journal. 56: 457–82. Bibcode:1922ApJ....56..457M. doi:10.1086/142716.
  3. ^ Merrill, P. W. (1952). "Technetium in the stars". Science. 115 (2992): 484.
  4. ^ George Sivulka (8 March 2017). "An Introduction to the Evidence for Stellar Nucleosynthesis". Stanford University. Retrieved 3 May 2018.
  5. ^ "Henry Draper Medal". National Academy of Sciences. Retrieved 24 February 2011.
  6. ^ "Past Winners of the Catherine Wolfe Bruce Gold Medal". Astronomical Society of the Pacific. Archived from the original on 6 October 2013. Retrieved 24 February 2011.
  7. ^ "Grants, Prizes and Awards". American Astronomical Society. Archived from the original on 24 January 2010. Retrieved 24 February 2011.
  8. ^ "Book of Members, 1780-2010: Chapter M" (PDF). American Academy of Arts and Sciences. Retrieved 16 April 2011.

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