S/2004 S 31

S/2004 S 31 is a natural satellite of Saturn and a member of the Inuit group. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019 from observations taken between December 12, 2004 and March 22, 2007.^[3]

S/2004 S 31

Discovery[1]
Discovered by	Sheppard et al.
Discovery date	2019
Designations
Alternative names	T522499[2]
Orbital characteristics[2]
Semi-major axis	17402800 km
Eccentricity	0.242
Orbital period (sidereal)	853.80 days
Inclination	48.11°
Satellite of	Saturn
Group	Inuit group (Siarnaq)
Physical characteristics[2]
Mean diameter	4 km
Apparent magnitude	24.9
Absolute magnitude (H)	15.6[3]

S/2004 S 31 is about 4 kilometres in diameter, and orbits Saturn at an average distance of 17.568 Gm in 869.65 days, at an inclination of 48.8° to the ecliptic, with an eccentricity of 0.240.^[3] The satellite is affected by the Kozai mechanism, and is noted to be the first known moon whose argument of periapsis oscillates around 270°.^[4]