253 Mathilde

253 Mathilde

Mathilde photographed by the NEAR Shoemaker spacecraft on 27 June 1997
Discovery
Discovered by	Johann Palisa
Discovery site	Vienna Obs.
Discovery date	12 November 1885
Designations
Pronunciation	/məˈtɪldə/
Named after	Mathilde Loewy
Alternative designations	A885 VA 1915 TN 1949 OL1
Minor planet category	main-belt (middle)
Orbital characteristics
Epoch 9 June 2026 (JD 2461200.5)
Uncertainty parameter 0
Aphelion	3.347 AU
Perihelion	1.947 AU
Semi-major axis	2.647 AU
Eccentricity	0.2643
Orbital period (sidereal)	4.31 yr (1,573 d)
Mean anomaly	273.534°
Mean motion	0° 13m 43.948s / day
Inclination	6.740°
Longitude of ascending node	179.494°
Argument of perihelion	157.564°
Known satellites	0
Proper orbital elements
Proper semi-major axis	2.648 AU
Proper eccentricity	0.219
Proper inclination	6.54°
Proper mean motion	83.5361 deg / yr
Proper orbital period	4.30951 yr (1574.05 d)
Precession of perihelion long.	52.8 arcsec / yr
Precession of asc. node	−63.3 arcsec / yr
Physical characteristics
Dimensions	66 km × 48 km × 46 km
Mean diameter	52.8±2.6 km
Volume	78000+12000 −11000 km3
Mass	(1.033±0.044)×1017 kg
Mean density	1.3±0.2 g/cm3
Equatorial surface gravity	0.00989 m/s2
Sidereal rotation period	17.406 ± 0.010 d (417.74 ± 0.24 h)
Geometric albedo	0.047±0.005
Temperature	≈ 174 K
Spectral type	Cb
Absolute magnitude (H)	10.35

253 Mathilde is an asteroid in the intermediate asteroid belt, approximately 50 kilometers in diameter, that was discovered by Austrian astronomer Johann Palisa at Vienna Observatory on 12 November 1885. It has a relatively elliptical orbit that requires more than four years to circle the Sun. This tumbling asteroid has an unusually slow rate of rotation, requiring 17.4 days to complete a 360° revolution about its axis. It is a primitive C-type asteroid, which means the surface has a high proportion of carbon; giving it a dark surface that reflects only 4% of the light that falls on it.

Mathilde was visited by the NEAR Shoemaker spacecraft during June 1997, on its way to asteroid 433 Eros. During the short flyby, the spacecraft imaged a hemisphere of the asteroid, revealing many large craters that had gouged out depressions in the surface. It was the first carbonaceous asteroid to be explored and, until 21 Lutetia was visited in 2010, it was the largest asteroid to be visited by a spacecraft.