24 Themis

Infobox Planet | discovery=yes | physical_characteristics = yes | bgcolour=#FFFFC0
name=24 Themis
discoverer=Annibale de Gasparis
discovered=April 5, 1853
alt_names=1947 BA; 1955 OH
mp_category=Main belt (Themis)
epoch=August 18, 2005 (JD 2453600.5)
semimajor=468.226 Gm (3.130 AU)
perihelion=406.202 Gm (2.715 AU)
aphelion=530.250 Gm (3.545 AU)
eccentricity=0.132
period=2022.524 d (5.54 a)
inclination=0.760°
asc_node=35.992°
arg_peri=107.989°
mean_anomaly=185.968°
avg_speed=16.76 km/s
dimensions=198 km MPCit_JPL|24| ^[1]
mass=5.75±2.51e|19 kg [ [http://www.psi.edu/pds/asteroid/EAR_A_5_DDR_ASTEROID_DENSITIES_V1_1 Index of /pds/asteroid/EAR_A_5_DDR_ASTEROID_DENSITIES_V1_1 ] ]
density=14±6 g/cm³ "doubtful"
surface_grav=0.39±0.27 m/s²
escape_velocity=0.88±0.22 km/s
rotation=0.34892 d (8 h 23 min) [ [http://www.psi.edu/pds/archive/lc.html] Dead link|date=March 2008] [ [http://www.astrosurf.com/aude-old/map_files/AstVarMAP01-2003.htm] Dead link|date=March 2008]
spectral_type=C [ [http://pdssbn.astro.umd.edu/SBNcgi/sbdbatt?objnum=32124 Small Bodies Attributes Utility Results ] ] (B-V=0.68)
abs_magnitude=7.08
albedo=0.067 [ [http://ssd.jpl.nasa.gov/cgi-bin/da Page Modified ] ]
single_temperature=~159 K

24 Themis (pronEng|ˈθiːmɪs, _gr. "Θέμις)" is one of the largest Main belt asteroids. It is also the largest member of the Themistian asteroid family.

It was discovered by Annibale de Gasparis on April 5, 1853. The mass and diameter appearing in the table are from separate sources, and combining them gives an unusually large density, which is most probably wrong. The mass has very likely been overestimated by a factor of at least five times.

It is named after Themis, the personification of divine order, law and custom in Greek mythology.

References