Quick facts
Parent planet
Diameter (mean)
22 km
Mass
1.1 × 10¹⁶ kg
1.5e-07 Moon masses
Mean orbital radius
11,165,000 km
Orbital period
240.9 Earth days
Discovery year
1974
Discoverer
Charles T. Kowal
Naming origin
Queen of Sparta, mother of Helen by Zeus
Surface conditions
Leda is a tiny 22-km member of the Himalia prograde group, discovered by Charles Kowal from Mount Palomar in 1974. No close imagery exists.
Missions and observations
Every Jupiter-system mission has had an opportunity to image or characterize Leda. The list below is the Jupiter-system mission catalog; specific Leda encounters are documented in mission archives.
| Mission | Year at Jupiter | Status |
|---|---|---|
|
Pioneer 10 NASA |
1973 | Completed |
|
Pioneer 11 NASA |
1974 | Completed |
|
Voyager 1 NASA |
1979 | Completed |
|
Voyager 2 NASA |
1979 | Completed |
|
Ulysses NASA/ESA |
1992 | Completed |
|
Galileo NASA |
1995 | Completed |
|
Cassini-Huygens NASA/ESA/ASI |
2000 | Completed |
|
New Horizons NASA |
2007 | Completed |
|
Juno NASA |
2016 | Active |
|
Europa Clipper NASA |
2030 | On the way |
|
JUICE ESA |
2031 | On the way |
Naming etymology
Leda was the Queen of Sparta whom Zeus seduced in the form of a swan; their daughter was Helen of Troy. The IAU adopted the name in 1975 — within months of discovery rather than the usual decades-long delay.
Methodology & sources
Diameter, mass, and orbital parameters from JPL Solar System Dynamics — Physical Parameters. Discovery year and discoverer from the JPL Satellite Discovery Circumstances. Naming etymology from the IAU Working Group for Planetary System Nomenclature. Stylized SVG hero composed from NASA / JPL imagery as visual reference; no photographs are reproduced.