Herse (// HUR-see; Greek: Ἕρση), or Jupiter L, previously known by its provisional designation of S/2003 J 17, is a natural satellite of Jupiter. It was discovered on 8 February 2003 by the astronomers Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, and Lynne Allen and also by a team of astronomers at the University of Hawaii. It was named after Herse 'dew', a daughter of Zeus and Selene the moon in Greek mythology, on 11 November 2009.
Herse is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 22.134 gigametre (Gm) in 672.752 days, at a mean inclination of 165° to the ecliptic, in a retrograde direction and with a mean eccentricity of 0.2493.
It is the innermost member of the Carme group, made up of irregular retrograde moons orbiting Jupiter at a distance ranging between 23 and 24 Gm and at an inclination of about 165°.
- Daniel W. E. Green, IAUC 8116: Satellites of Jupiter and Saturn 2003 April 11 (discovery)
- Brian G. Marsden, MPEC 2003-G19: S/2003 J 17 2003 April 3 (discovery and ephemeris)
- Jennifer S. Blue, L Named Herse, 2009 November 9
- Jennifer S. Blue, IAUC 9094: Satellite of Jupiter (subscription required) 2009 November 11 (naming)
- Planetary Satellite Mean Orbital Parameters, JPL