Paul W. Merrill

Paul W. Merrill
Born	Paul Willard Merrill August 15, 1887
Died	July 19, 1961 (1961-07-20) (aged 73)
Nationality	American
Occupation	astronomer
Years active	1913–1952
Known for	Studying unusual stars, particularly long-period variable stars, using spectroscopy

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

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.

Honors

Awards and honors

• Henry Draper Medal of the National Academy of Sciences (1945)
• Bruce Medal of the Astronomical Society of the Pacific (1946)
• Henry Norris Russell Lectureship of the American Astronomical Society (1955)
• Fellow of the American Academy of Arts and Sciences (1958)

Named after him

• Merrill (crater) on the Moon

External links

• Paul Willard Merrill — Biographical Memoirs of the National Academy of Sciences