98 Ianthe

98 Ianthe is a large main-belt asteroid, named for three figures in Greek mythology. It is very dark and is composed of carbonates. It was one of the numerous (for his time—the 19th century) discoveries by C. H. F. Peters, who found it on April 18, 1868, from Clinton, New York.

98 Ianthe

Three-dimensional model of 98 Ianthe created based on light-curve.
Discovery
Discovered by	Christian Heinrich Friedrich Peters
Discovery date	18 April 1868
Designations
MPC designation	(98) Ianthe
Pronunciation	/aɪˈænθiː/[1]
Named after	Ianthe
Minor planet category	Main belt
Adjectives	Ianthean /aɪənˈθiːən/[2]
Orbital characteristics[3]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	145.23 yr (53047 d)
Aphelion	3.18807 AU (476.928 Gm)
Perihelion	2.18872 AU (327.428 Gm)
Semi-major axis	2.68839 AU (402.177 Gm)
Eccentricity	0.18586
Orbital period (sidereal)	4.41 yr (1610.0 d)
Average orbital speed	18.01 km/s
Mean anomaly	262.019°
Mean motion	0° 13m 24.949s / day
Inclination	15.5778°
Longitude of ascending node	354.000°
Argument of perihelion	158.686°
Earth MOID	1.20327 AU (180.007 Gm)
Jupiter MOID	1.81554 AU (271.601 Gm)
TJupiter	3.296
Physical characteristics
Dimensions	104.45±1.8 km[3] 106.16 ± 3.76 km[4]
Mass	(8.93 ± 1.99) × 1017 kg[4]
Mean density	1.42 ± 0.35 g/cm3[4]
Equatorial surface gravity	0.0292 m/s2 (0.00298 g0)
Equatorial escape velocity	0.0552 km/s
Synodic rotation period	16.479 h (0.6866 d)[3][5]
Geometric albedo	0.0471±0.002[3] 0.047[6]
Temperature	~170 K
Spectral type	C
Absolute magnitude (H)	8.84

This body is orbiting the Sun with a period of 4.41 years and an eccentricity of 0.186. The orbital plane is inclined at an angle of 15.6° to the plane of the ecliptic. Measurements of the cross-section dimension yield a size of around 105 km. Photometric observations of this asteroid during 2007 at the Organ Mesa Observatory in Las Cruces, New Mexico were used to create a light curve plot. This showed a synodic rotation period of 16.479±0.001 hours and a brightness variation of 0.27±0.02 magnitude during each cycle.^[5] It is classified as a C-type asteroid, indicating a dark, carbonaceous surface.

The detection of a candidate moon orbiting 98 Ianthe was announced in 2004.^[7]