Mark R. Showalter | |
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| Born | Mark Robert Showalter (1957-12-05)December 5, 1957 (age 67) Abington, Pennsylvania, U.S. |
| Nationality | American |
| Alma mater | Oberlin College (B.A.);Cornell University (M.Sc.), (Ph.D.) |
| Known for | Discoverer or co-discoverer of Jovian gossamer ring, Saturnian moonPan, Uranian moonsMab andCupid, Uranian rings μ and ν, Neptunian moonHippocamp, Plutonian moonsKerberos andStyx |
| Spouse | Frank Yellin |
| Scientific career | |
| Fields | Astronomy,astrophysics,space science,planetary science |
| Institutions | SETI Institute |
Mark Robert Showalter (born December 5, 1957) is an American senior research scientist at theSETI Institute.[1] He is the discoverer of six moons and three planetary rings. He is the Principal Investigator of NASA'sPlanetary Data System Rings Node, a co-investigator on theCassini–Huygens mission toSaturn, and works closely with theNew Horizons mission toPluto.[2]
Showalter was born inAbington, Pennsylvania. He enjoyed playing with science-themed toys while a child, and later mowed lawns as a teenager so that he might purchase atelescope in high school. He received aBachelor of Arts inphysics andmathematics fromOberlin College in 1979. He was initially undecided about pursuing a career inastronomy after his undergraduate education, but made up his mind after seeing the images of Jupiter sent back to Earth byVoyager 2.[3]
Showalter received hisMS inastronomy fromCornell University in 1982, and hisPhD from Cornell in 1985.[3][4] His thesis was onJupiter'sring system, in which he discoveredthe gossamer ring of Jupiter.[a][5]
In 1990, using ten-year-oldVoyager data, Showalter discoveredPan, the eighteenth and innermostmoon of Saturn. It orbits within and keeps open theEncke Gap in Saturn's rings via shepherding.[6][7]
In 2003, Showalter andJack J. Lissauer discovered two new moons ofUranus (Mab andCupid) inHubble Space Telescope images.[7][8] In 2006, they announced the discovery of two very faint rings, the μ and ν rings, within the same data.[9][10]
In 2010, Showalter discovered that spiral vertical corrugations in Jupiter's rings were caused by the impact ofComet Shoemaker–Levy 9 in July 1994. A second smaller set of corrugations appear to be consistent with an unknown impact in early 1990. He and co-researchers also found similar spiral patterns in Saturn's D Ring.[11][12][13][14]
Showalter has assisted the New Horizons team in determining what hazards the spacecraft would encounter as it flew close to Pluto. A search for faint dust rings of Pluto using the Hubble Space Telescope in 2011 led to the discovery of the fourth moonKerberos.[7][15] Working with the New Horizons team, Showalter found the fifth moonStyx in July 2012.[16][17]
On July 15, 2013, a team of astronomers led by Showalter discovered a previously unknown fourteenth moon of Neptune in images taken by the Hubble Space Telescope from 2004 to 2009. Unnamed at that time,Hippocamp is thought to measure around 34.8 km in diameter.[18]
Showalter was the 2021 recipient of theHarold Masursky Award for Meritorious Service to Planetary Science.[19]
TheMars-crossing asteroid18499 Showalter is named after Dr. Showalter.
Showalter is an avidscuba diver andphotographer. He is married to Frank Yellin; they live in California.[2][20]
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