Ersa (moon)

Ersa

Discovery
Discovered by	Scott S. Sheppard et al.
Discovery date	11 May 2018
Designations
Designation	Jupiter LXXI
Pronunciation	/ˈɜːrsə/
Named after	Ἔρσα Ersa
Alternative names	S/2018 J 1
Orbital characteristics
Semi-major axis	11483000 km
Eccentricity	0.094
Orbital period (sidereal)	+252.0 days
Mean anomaly	356.6°
Inclination	30.61°
Longitude of ascending node	93.3°
Argument of perihelion	346.7°
Satellite of	Jupiter
Group	Himalia group
Physical characteristics
Mean diameter	3 km
Apparent magnitude	22.9

Ersa /ˈɜːrsə/, also Jupiter LXXI, originally known as S/2018 J 1, is an outer natural satellite of Jupiter. It was discovered by Scott S. Sheppard and his team on 11 May 2018, and was later announced on 17 July 2018, via a Minor Planet Electronic Circular from the Minor Planet Center. It is about 3 kilometres (2 mi) in diameter and has an orbit radius of around 11,483,000 kilometres (7,135,000 miles); its orbital inclination is about 30.61°. It belongs to the Himalia group.

Name

The moon was named in 2019 after Ersa, the Greek goddess of dew, daughter of Zeus and Selene: Jupiter L Herse is also named for this goddess. The name was suggested in a naming contest held by the Carnegie Institute on Twitter where more than twenty tweets suggested the name, including Aaron Quah (@8603103) who submitted the name first, StSauveur_MoonsProject (@StSauMoons) that are the 12th grade students of Saint Sauveur High School in Redon, France, the fifth grade at Hillside Traditional Academy in British Columbia, Canada (submitted on their behalf by @mrgrouchypants), and a 4-year-old child who sang a song about Ersa (submitted on his behalf by @Thoreson).