Philophrosyne (moon)


Discovered byScott Sheppard et al.
Discovery date2003
Jupiter LVIII
Pronunciation/fɪləˈfrɒsən/ or /-ˈfrɒzən/
Named after
Φιλοφροσύνη Philophrosynē
S/2003 J 15
AdjectivesPhilophrosynean /fɪˌlɒfrəzəˈnən/
Orbital characteristics[1]
22819950 km
−701.3 days
Satellite ofJupiter
GroupPasiphae group
Physical characteristics
Mean diameter
2 km

Philophrosyne (/fɪləˈfrɒsən/ or /fɪləˈfrɒzən/), also Jupiter LVIII and provisionally known as S/2003 J 15, is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2003,[2][3] but then lost.[4][5][6][7] It was recovered in 2017 and given its permanent designation that year.[8]


Philophrosyne is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 22,721,000 km in 699.676 days, at an inclination of 142° to the ecliptic (142° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.0932.

It belongs to the Pasiphae group, retrograde irregular moons that orbit Jupiter between 22.8 and 24.1 Gm, at inclinations of roughly 150-155°.


The moon was named in 2019 after Philophrosyne (Φιλοφροσύνη), the ancient Greek spirit of welcome, friendliness, and kindness, the daughter of Hephaestus and Aglaea and granddaughter of Zeus. The name originated from a naming contest held on Twitter where it is suggested by users including CHW3M Myth Experts (@Chw3mmyths) which is an 11th-grade history class studying Greek and Roman philosophy as of 2019, Victoria (@CharmedScribe), and Lunartic (@iamalunartic) who has concurrently helped in naming another Jovian moon Eupheme.[9][10][11]


  1. ^ S.S. Sheppard (2019), Moons of Jupiter, Carnegie Science, on line
  2. ^ IAUC 8116: Satellites of Jupiter and Saturn Archived 2006-05-05 at the Wayback Machine 2003 April (discovery)
  3. ^ MPEC 2003-G17: S/2003 J 15 2003 April (discovery and ephemeris)
  4. ^ Beatty, Kelly (4 April 2012). "Outer-Planet Moons Found — and Lost". Sky & Telescope. Retrieved 27 June 2017.
  5. ^ Brozović, Marina; Jacobson, Robert A. (9 March 2017). "The Orbits of Jupiter's Irregular Satellites". The Astronomical Journal. 153 (4): 147. Bibcode:2017AJ....153..147B. doi:10.3847/1538-3881/aa5e4d.
  6. ^ Jacobson, B.; Brozović, M.; Gladman, B.; Alexandersen, M.; Nicholson, P. D.; Veillet, C. (28 September 2012). "Irregular Satellites of the Outer Planets: Orbital Uncertainties and Astrometric Recoveries in 2009–2011". The Astronomical Journal. 144 (5): 132. Bibcode:2012AJ....144..132J. doi:10.1088/0004-6256/144/5/132.
  7. ^ Sheppard, Scott S. (2017). "New Moons of Jupiter Announced in 2017". Retrieved 27 June 2017. We likely have all of the lost moons in our new observations from 2017, but to link them back to the remaining lost 2003 objects requires more observations a year later to confirm the linkages, which will not happen until early 2018. ... There are likely a few more new moons as well in our 2017 observations, but we need to reobserve them in 2018 to determine which of the discoveries are new and which are lost 2003 moons.
  8. ^ Sheppard, Scott S. (2017). "Jupiter's Known Satellites". Archived from the original on 18 March 2015. Retrieved 10 August 2017.
  9. ^ "Planet and Satellite Names and Discoverers". USGS Astrogeology Science Center. Retrieved 27 August 2019.
  10. ^ "Naming Contest for Newly-discovered Moons of Jupiter". Retrieved 27 August 2019.
  11. ^ "Public Contest Successfully Finds Names For Jupiter's New Moons". Retrieved 27 August 2019.