Mark R. Showalter
| Mark R. Showalter | |
|---|---|
| File:MarkRShowalter.jpg | |
| Born | Mark Robert Showalter December 5, 1957 Abington, Pennsylvania, U.S. |
| Residence | California, U.S. |
| Nationality | American |
| Fields | Astronomy, astrophysics, space science, planetary science |
| Institutions | SETI Institute |
| Alma mater | Oberlin College (B.A.); Cornell University (M.Sc.), (Ph.D.) |
| Known for | Discoverer or co-discoverer of Jovian gossamer ring, Saturnian moon Pan, Uranian moons Mab and Cupid, Uranian rings μ and ν, Neptunian moon S/2004 N 1, Plutonian moons Kerberos and Styx |
| Spouse | Frank Yellin |
Mark Robert Showalter (born December 5, 1957) is a Senior Research Scientist at the SETI Institute.[1] He is the discoverer of six moons and three planetary rings. He is the Principal Investigator of NASA's Planetary Data System Rings Node, a co-investigator on the Cassini–Huygens mission to Saturn, and works closely with the New Horizons mission to Pluto.[2]
Biography
Showalter was born in Abington, Pennsylvania. He enjoyed playing with science-themed toys while a child, and later mowed lawns as a teenager so that he might purchase a telescope in high school. He received a Bachelor of Arts in physics and mathematics from Oberlin College in 1979. He was initially undecided about pursuing a career in astronomy after his undergraduate education, but made up his mind after seeing the images of Jupiter sent back to Earth by Voyager 2.[3]
Showalter received his MS in astronomy from Cornell University in 1982, and his PhD from Cornell in 1985.[3][4] His thesis was on Jupiter's ring system, in which he discovered the gossamer ring of Jupiter.[lower-alpha 1][5]
In 1990, using ten-year-old Voyager data, Showalter discovered Pan, the eighteenth and innermost moon of Saturn. It orbits within and keeps open the Encke Gap in Saturn's rings via shepherding.[6][7]
In 2003, Showalter and Jack J. Lissauer discovered two new moons of Uranus (Mab and Cupid) in Hubble 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 of Comet 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 moon Kerberos.[7][15] Working with the New Horizons team, Showalter found the fifth moon Styx in July 2012.[16][17]
On July 15, 2013, a team of astronomers led by Mark Showalter of the SETI Institute discovered a previously unknown fourteenth moon in images taken by the Hubble Space Telescope from 2004 to 2009. The as yet unnamed fourteenth moon of Neptune, currently known as S/2004 N 1, is thought to measure no more than 20 km in diameter.[18]
The Mars-crossing asteroid 18499 Showalter is named after Dr. Showalter.
Personal life
Showalter is an avid scuba diver and photographer. He is married to Frank Yellin; they live in California.[2][19]
Notes
- ↑ At the time of discovery, the gossamer ring was thought to be a single ring. Later observations have resolved the gossamer ring into two separate, overlapping rings: the Thebe gossamer ring and the Amalthea gossamer ring.
References
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- ↑ Beatty, Kelly. "Neptune's Newest Moon." Sky and Telescope. July 15, 2013. Accessed 2013-07-17.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
External links
- Mark Showalter's SETI Institute home page
- Planetary Data System rings node home page
- Silicon Valley Astronomy Lectures, November 12, 2008 on YouTube Saturn's Restless Rings: Results from the Cassini Mission
- Silicon Valley Astronomy Lectures, Jan. 28, 2015 on YouTube Pluto on the Horizon: Anticipating our First Encounter with the Double Planet
