26 Proserpina

26 Proserpina is a main-belt asteroid discovered by German astronomer R. Luther on May 5, 1853. It is named after the Roman goddess Proserpina, the daughter of Ceres and the Queen of the Underworld. Another main-belt asteroid, 399 Persephone, discovered in 1895, is named after her Greek counterpart. Its historical symbol was a star inside a pomegranate; it is in the pipeline for Unicode 17.0 as U+1CECD 𜻍 ().^[7][8]

26 Proserpina

Three-dimensional model of 26 Proserpina created based on light-curve inversions.
Discovery
Discovered by	R. Luther
Discovery date	May 5, 1853
Designations
MPC designation	(26) Proserpina
Pronunciation	/proʊˈsɜːrpɪnə/[1]
Named after	Proserpina
Alternative designations	1935 KK; 1954 WD1
Minor planet category	Main belt
Adjectives	Proserpinian /ˌprɒsərˈpɪniən/[2]
Symbol	(historical)
Orbital characteristics
Epoch June 14, 2006 (JD 2453900.5)
Aphelion	431.898 Gm (2.887 AU)
Perihelion	362.816 Gm (2.425 AU)
Semi-major axis	397.357 Gm (2.656 AU)
Eccentricity	0.087
Orbital period (sidereal)	1581.184 d (4.33 a)
Mean anomaly	115.619°
Inclination	3.562°
Longitude of ascending node	45.884°
Argument of perihelion	193.120°
Physical characteristics
Dimensions	94.8 ± 1.7 km (IRAS)[3] 89.63 ± 3.55 km[4]
Mass	(7.48 ± 8.95) × 1017 kg[4]
Mean density	1.98 ± 2.38 g/cm3[4]
Synodic rotation period	13.11 h[3][5]
Geometric albedo	0.1966[3][6]
Spectral type	S[3]
Absolute magnitude (H)	7.5[3]

This object is orbiting the Sun with a period of 4.33 years. It has a cross-section size of around 90 km and a stony (S-type) composition. Photometric observations of this asteroid have produced discrepant estimates of the rotation period. A period of 12.13 hours was reported in 1979, followed by 10.6 hours in 1981 and 6.67 hours in 2001. Observations made in 2007 at the Oakley Observatory in Terre Haute, Indiana produced a light curve with a period of 13.06 ± 0.03 hours and a brightness variation of 0.21 ± 0.01 in magnitude.^[9] This was refined by a 2008 study, giving a period of 13.110 ± 0.001 hours.^[10]