99 Dike

Also known as (99) Dike, Dike

main-belt asteroid

Picture of the Day · NASA

Pathfinder on Mars

2026-07-04

On July 4th, 1997, using its own array of fireworks, a parachute, and a cocoon of airbags, the Mars Pathfinder spacecraft bounced like a giant beach ball at least 15 times before it came to rest on the surface of Mars at 10:07 AM Pacific Daylight Time. After its then novel airbag-assisted landing sequence was completed, Pathfinder transmitted this color mosaic to mission operators on Earth. In the scene from another world, the Mars Sojourner robot rover is visible in the foreground, crouched on top of the unfolded Pathfinder. About the size of a large house cat, the six-wheeled, solar-powered Sojourner became the first successful Martian rover. Surrounding Pathfinder are deflated airbags and the rock-strewn terrain of the Ares Vallis floodplain. In the distance Martian hills appear against a dusty brownish sky. The Pathfinder lander was subsequently renamed the Carl Sagan Memorial Station.

via NASA APOD

Key facts

Discovered by: Alphonse Borrelly
Discovery date: 28 May 1868
Pronunciation: / ˈ d aɪ k iː /
Named after: Dike
Alternative designations: A915 BA; 1935 UC; 1935 YL; 1939 UT; 1948 UE; 1948 WC; 1961 XJ; 1974 VB
Minor planet category: Main belt
Adjectives: Dikean / d aɪ ˈ k iː ə n /
Observation arc: 101.25 yr (36980 d)
Aphelion: 3.18448 AU (476.391 Gm )
Perihelion: 2.14561 AU (320.979 Gm)
Semi major axis: 2.66504 AU (398.684 Gm)
Orbital period sidereal: 4.35 yr (1589.1 d )
Average orbital speed: 18.07 km/s
Mean anomaly: 18.1950 °
Mean motion: 0° 13 35.551 / day
Inclination: 13.8487°
Longitude of ascending node: 41.5307°
Argument of perihelion: 195.413°

via Wikipedia infobox

Wikidata facts

Diameter: 67.354
Mass: 390
Orbital period: 1587.500800012039
Image: 99Dike (Lightcurve Inversion).png

Show 15 more facts

provisional designation: A868 KA
time of discovery or invention: 1868-05-28
orbital inclination: 13.86365348724321
albedo: 0.065
Commons category: 99 Dike
rotation period: 18.127
absolute magnitude: 9.47
orbital eccentricity: 0.1977126544567734
semi-major axis of an orbit: 2.663240279873327
periapsis: 2.136683974683371
apoapsis: 3.189796585063282
longitude of ascending node: 41.40222854540891
argument of periapsis: 195.4278237258741
mean anomaly: 68.65213772371538
time of periapsis: 2460697.7629901143

Sources (2)

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Article

99 Dike (/ˈdaɪkiː/) is a quite large and dark main-belt asteroid. Dike was discovered by Alphonse Borrelly on May 28, 1868. It was his first asteroid discovery. This object is named after Dike, the Greek goddess of moral justice. Among the first hundred numbered minor planets, 99 Dike was considered anomalously faint for over a century. However, this was later found to be untrue.

This asteroid is orbiting the Sun with a period of 4.35 years and an eccentricity of 0.19. Its orbital plane is inclined by 13.8° to the plane of the ecliptic. The body spans a diameter of 69 km and it is classified as a C-type asteroid, which indicates it has a dark, carbonaceous surface. Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of 18.127 ± 0.002 hours and varies in brightness by 0.22 ± 0.02 in magnitude. However, according to Shrindan E. (2009) the rotation period is rather of 10.360 ± 0.001 h.