Scott Sander Sheppard (born 1977) is an American astronomer and a discoverer of numerous moons, comets and minor planets in the outer Solar System.[1][2][3]
He is an astronomer in the Department of Terrestrial Magnetism at the Carnegie Institution for Science in Washington, DC. He attended Oberlin College as an undergraduate, and received his bachelor in physics with honors in 1998.[4][better source needed] Starting as a graduate student at the Institute for Astronomy at the University of Hawaiʻi at Mānoa, he was credited with the discovery of many small moons of Jupiter, Saturn, Uranus, and Neptune. He has also discovered the first known trailing Neptune trojan, 2008 LC18, the first named leading Neptune trojan, 385571 Otrera, and the first high inclination Neptune trojan, 2005 TN53. These discoveries showed that the Neptune trojan objects are mostly on highly inclined orbits and thus likely captured small bodies from elsewhere in the Solar System.
The main-belt asteroid 17898 Scottsheppard, discovered by LONEOS at Anderson Mesa Station in 1999, was named in his honor.[1]
Sheppard was the lead discoverer of the object with the most distant orbit known in the Solar System, 2012 VP113 (nicknamed Biden). In 2014, the similarity of the orbit of 2012 VP113 to other extreme Kuiper belt object orbits led Sheppard and Trujillo to propose that an unknown Super-Earth mass planet (2–15 Earth masses) in the outermost Solar System beyond 200 AU and up to 1500 AU is shepherding these smaller bodies into similar orbits (see Planet X or Planet Nine). The extreme trans-Neptunian objects 2013 FT28 and 2014 SR349, announced in 2016 and co-discovered by Sheppard, further show a likely unknown massive planet exists beyond a few hundred AU in the Solar System, with 2013 FT28 being the first known high semi-major axis and high perihelion object anti-aligned with the other known extreme objects. In 2018, the announcement of the high perihelion inner Oort cloud object 541132 Leleākūhonua (nicknamed "The Goblin") by Sheppard et al., being only the third known after 2012 VP113 and Sedna, further demonstrated that a super-Earth planet in the distant solar system likely exists as Leleākūhonua has many orbital similarities as the two other known inner Oort cloud objects.
Sheppard has been involved in the discovery of many small Solar System bodies such as trans-Neptunian objects, centaurs, comets and near-Earth objects.
Discovered moons of Jupiter (full list):[3]
Discovered moons of Saturn (full list):[3]
Discovered moons of Uranus (full list):[3]
Discovered moons of Neptune (full list):[3]