| Minorplanet: | yes |
| Background: |
|
| 98 Ianthe | |
| Discovered: | 18 April 1868 |
| Mpc Name: | (98) Ianthe |
| Pronounced: | [1] |
| Adjective: | Ianthean [2] |
| Epoch: | 31 July 2016 (JD 2457600.5) |
| Semimajor: | 2.68839AU |
| Perihelion: | 2.18872AU |
| Aphelion: | 3.18807abbr=onNaNabbr=on |
| Eccentricity: | 0.18586 |
| Period: | 4.41 yr (1610.0 d) |
| Inclination: | 15.5778° |
| Asc Node: | 354.000° |
| Arg Peri: | 158.686° |
| Avg Speed: | 18.01 km/s |
| Dimensions: | 106.16 ± 3.76 km |
| Density: | 1.42 ± 0.35 g/cm3 |
| Surface Grav: | 0.0292 m/s² |
| Escape Velocity: | 0.0552 km/s |
| Rotation: | 16.479abbr=onNaNabbr=on |
| Abs Magnitude: | 8.84 |
| Albedo: | 0.047 [3] |
| Mean Motion: | / day |
| Orbit Ref: | [4] |
| Observation Arc: | 145.23 yr (53047 d) |
| Uncertainty: | 0 |
| Moid: | 1.20327AU |
| Jupiter Moid: | 1.81554AU |
| Tisserand: | 3.296 |
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.
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 hours and a brightness variation of magnitude during each cycle. 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.