Dick Walker (astronomer)

American astronomer (1936–2005)

Dick Walker

Born| (1936-03-09)March 9, 1936

Hampton, Iowa

Died| March 30, 2005(2005-03-30) (aged 69)

Flagstaff, Arizona

Occupation| Astronomer
Academic background
Education|

* University of Northern Iowa
* University of Iowa (BS)
* Georgetown University

Richard Lee Walker Jr. (March 9, 1938 – March 30, 2005) was an American astronomer known for his observations of double stars and for discovering Epimetheus, an inner moon of Saturn. Interested in astronomy since his youth, he graduated from the University of Iowa in 1963 after studying physics and astronomy under James Van Allen and Satoshi Matsushima. He began work at the United States Naval Observatory (USNO) in Washington, D. C., in 1963, but transferred to the USNO Flagstaff Station in 1966. Shortly after his arrival in Flagstaff, he discovered a small inner moon of Saturn. Initially identified with Audouin Dollfus' newly-discovered Janus, it was identified as a separate moon twelve years later and named Epimetheus. He retired from the Naval Observatory in 1999, although continued to work as an astronomical consultant.

## Biography[edit]

On March 9, 1938, Richard Lee Walker Jr. was born in Hampton, Iowa, to Mary and Richard L. Walker. He spent most of his childhood in Waterloo, Iowa, where he attended school. He was fascinated by astronomy from an early age, building a homemade telescope and reading many astronomy texts. He began college at the University of Northern Iowa in 1957, before transferring to the State University of Iowa in 1959. He studied astronomy under James Van Allen and Satoshi Matsushima. He joined the American Astronomical Society in 1960, on the urging of Matsushima, and graduated with a BA in astronomy and physics in 1963.[1][2]

Epimentheus as imaged by Cassini in 2007

He began work for the Time Service of the United States Naval Observatory (USNO) later in 1963, working under William Markowitz in Washington, D.C. While with the Time Service, he wrote a Fortran program to model lunar libration. Unhappy with the work at the Time Service, he transferred to the USNO's Astrometry and Astrophysics Division the following year. He was assigned to the photographic double star program under Stewart Sharpless and Kaj Strand. While working for the observatory, he pursued some graduate training at the Georgetown Observatory, studying under Robert E. Wilson. However, he declined to finish a master's degree in order to focus on his career work.[1][2]

He transferred to the USNO Flagstaff Station in 1966, where he continued his observations of double and binary stars with the station's 40-inch and 61-inch reflectors. He frequently traveled to the Lick Observatory, near San Jose, California, in order to use its 36-inch Clark Refractor. On December 18, 1966, he discovered a small inner moon of Saturn, later named Epimetheus. However, this was initially identified with Audouin Dollfus' nearly simultaneous discovery of Janus. The two moons were though to be identical until October 1978, when astronomers Stephen M. Laerson and John W. Fountain identified them as two separate objects in similar orbits. This was confirmed three years later by Voyager 1's flyby of Saturn.[1][3]

During his period of work on double stars, he made over 8,000 measurements. This resulted in the discovery of 22 binary stars, usually from known systems.[4] He retired from the Naval Observatory in May 1999, although continued some work as a consultant for astronomical construction projects. On March 30, 2005, he died in Flagstaff after a long period of illness.[1]

## References[edit]

1. ^ a b c d Pier & Mason 2005, pp. 3–4.
2. ^ a b Walker, Richard; DeVorkin, David (January 13, 1997). "Oral History Interviews: Richard Walker".
3. ^ "Epimetheus". Cassini Solstice Mission. JPL/NASA. Archived from the original on 13 November 2016. Retrieved 17 December 2016.
4. ^ Evans et al. 2006, p. 1548.

### Bibliography[edit]

* Pier, Jeffery R.; Mason, Brian (2005). "Obituary: Richard L. (Dick) Walker, Jr., 1938-2005". Bulletin of the American Astronomical Society. 37 (4): 1558–1559.
* Evans, Nancy Remage; Franz, Otto; Massa, Dereck; Mason, Brian; Walker, Richard L.; Karovska, Margarita (2006). "Cepheids in Multiple Systems: ADS 14859". Publications of the Astronomical Society of the Pacific. 118 (849): 1545–1549. doi:10.1086/509791.