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Dorothy N. Davis Locanthi (1913–1999)

Published onDec 01, 2000
Dorothy N. Davis Locanthi (1913–1999)

Dorothy Davis Locanthi, a long-time AAS member, died in Glendale, California on September 27, 1999. An only child, she was born Dorothy N. Davis on April 19, 1913 in East St. Louis, IL, where she attended public schools and graduated from high school in three years. After one year at Ferry Hall, a college preparatory school in Lake Forest, IL, she entered Vassar College in 1929. There she majored in physics and took all the astronomy courses she could under Caroline Furness and Maud Makemson. By the time Dorothy graduated in 1933, she had decided there could be no more rewarding career for her than astrophysical research.

She wanted to enter the University of California (UC), where she was accepted, but its funds were limited because of the Great Depression. Her father, a small businessman, was also hit hard by the Depression so Dorothy had to depend on scholarships and her earnings from campus jobs to finance her education. Luckily she received a one-year teaching fellowship at Mills College in Oakland, close to Berkeley and Lick Observatory. At Mills Dorothy wrote an excellent master's thesis on the spectra of S stars, based on spectrograms taken by Paul Merrill at Mount Wilson Observatory. C. Donald Shane of the Berkeley Astronomical Department was her mentor. That Christmas she spent her "vacation" at Mount Hamilton working on her thesis, reading in the library and hoping for a clear night.

In 1934 Dorothy finally received a small assistantship and entered UC. In her third year she was awarded a Lick Observatory Fellowship. Most of the astronomy graduate students divided their time between the two locations. She wrote an outstanding thesis on the spectrum of Antares, based again on high-dispersion spectrograms from Mount Wilson, photographed primarily by Walter S. Adams and Theodore Dunham. Her principal advisers were Shane and the physicist, F.A. Jenkins. Dorothy became an expert on molecular spectra and in identifying many atomic lines of rare elements in this cool supergiant. She completed her PhD in 1937, and then accepted two successive one-year temporary teaching positions at Vassar and Smith. But what she really wanted was to continue research.

Dorothy then received an AAUW postdoctoral fellowship which enabled her to begin work on the spectrum of β Pegasi, an M giant with essentially the same effective temperature as Antares, but a higher density. She did this research at Mount Wilson Observatory, using spectrograms taken there. In 1940 she went to Princeton University as an assistant to Henry Norris Russell. She helped analyze the laboratory spectrum of Eu II. In 1942 Dorothy returned to Mount Wilson as an assistant to Adams and continued her own analysis of β Pegasi. By then America was at war and Mount Wilson was involved in several weapons development programs. She worked on them for a time, and then transferred to Caltech's rocket project. In 1943 she married Bart N. Locanthi, a Caltech student and electronics expert who also worked on this project.

In 1945 Dorothy was at Ray Control Company in Pasadena for a time under Pol Swings, the Belgian astrophysicist who was designing spectrographs for wartime industries. When the war ended she took a well-paying job in the nascent Beckman Laboratory to support her husband until he finished his degree at Caltech. Their first daughter was born in 1948, and Dorothy could not get back to work for two years. In 1950 she started at a half-time job with Franklin E. Roach, the former astronomer who had switched to night-sky research at the Naval Ordnance Test Station, Inyokern, California with an office in Pasadena. But in 1952 the Locanthis' second daughter was born, and Dorothy went back to full-time motherhood until 1962, seven years after their only son, Bart, Jr., was born. Then she was able to get a half-time job at Caltech under Jesse Greenstein, measuring and analyzing his spectrograms of S stars, especially R Andromedae. However, that job ended in 1969 as a result of cuts of government funding of scientific research. But in 1972 Dorothy succeeded in getting another half-time job, this one at JPL. By then her husband was a highly successful engineer, but she lived for science and continued at JPL well into the 1980's, though at reduced hours.

Dorothy loved scientific research, especially measuring and analyzing the spectra of late-type stars, at which she was a master. Mathematically highly gifted, she was an excellent numerical computer, but in the wartime and government projects she was generally assigned to supervise numbers of less adept women, a duty she did not relish. Her published papers on Antares, β Pegasi, S stars, and molecules in cool stars are her great monuments. She enjoyed travel and attending meetings, and presented papers at numerous AAS, ASP, and IAU sessions.

In the early 1990's Dorothy began suffering short-term memory problems. After that she lived with one or the other of her two daughters, Jeanne McLaughlin and Carol Ann Wainwright. Dorothy never had the permanent, full-time research position in astrophysics for which her training, experience, and published papers clearly qualified her, but she certainly made the most of the opportunities she did have.

There are a number of letters to, from, and about Dorothy in the Mary Lea Shane Archives of the Lick Observatory, University of California, Santa Cruz and in the Mount Wilson Observatory Collection, Huntington Library, San Marino. An obituary article for her was published in Physics Today, 53, April issue, p. 88, 2000.

Photo courtesy of the Mary Lea Shane Archives, Lick Observatory, UCSC

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