File:The_Antiope_Doublet_-_Eso0718b.png · Wikimedia Commons · See Wikimedia Commons
90 Antiope is an asteroid located in the main belt between Mars and Jupiter that is unusual because it consists of two similarly-sized bodies orbiting each other as a binary system. It matters to astronomers because studying double asteroids like this one helps them understand how asteroids form and behave in space.
AI-generated from the Wikipedia summary — may contain errors.
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
- Robert Luther
- Discovery date
- 1 October 1866
- Pronunciation
- / æ n ˈ t aɪ ə p iː /
- Alternative designations
- 1952 BK 2
- Minor planet category
- Main belt , ( Themis family )
- Adjectives
- Antiopean
- Aphelion
- 3.6494 AU
- Perihelion
- 2.6606 AU
- Semi major axis
- 3.1550 AU
- Orbital period sidereal
- 2046.9 d (5.60 yr )
- Average orbital speed
- 16.66 km/s
- Mean anomaly
- 304.12°
- Inclination
- 2.2195°
- Longitude of ascending node
- 70.21°
- Argument of perihelion
- 242.96°
- Dimensions
- 93.0×87.0×83.6 km , 87.8 ± 1.0 km
- Mass
- 8.3×10 kg, (whole system) , ~ 4.1−4.2 × 10 kg (components)
- Mean density
- 1.25 ± 0.05 g/cm (each)
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Followed by
- 91 Aegina
- Follows
- 89 Julia
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 115.974
- Mass
- 830
- Orbital period
- 2033.554819521395
- Image
- ESO - The double asteroid Antiope (by).jpg
Show 20 more facts
- discoverer or inventor
- Robert Luther
- site of astronomical discovery
- Düsseldorf-Bilk Observatory
- provisional designation
- A866 TA
- time of discovery or invention
- 1866-10-01
- asteroid spectral type
- C-type asteroid
- orbital inclination
- 2.2054001746626
- Commons category
- 90 Antiope
- albedo
- 0.058
- described by source
- Brockhaus and Efron Encyclopedic Dictionary
- rotation period
- 16.509
- absolute magnitude
- 8.43
- orbital eccentricity
- 0.1724465529568321
- semi-major axis of an orbit
- 3.141267866094408
- periapsis
- 2.599567050672364
- apoapsis
- 3.682968681516453
- longitude of ascending node
- 69.89101743025401
- argument of periapsis
- 244.3683738267035
- mean anomaly
- 209.1021016654577
- time of periapsis
- 2461852.886523372
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~6 min read
Encyclopedic overview
90 Antiope is a double asteroid in the outer asteroid belt. It was discovered on 1 October 1866, by Robert Luther. In 2000, it was found to consist of two almost-equally-sized bodies orbiting each other. At average diameters of about 88 km and 84 km, both components are among the 500 largest asteroids. Antiope is a member of the Themis family of asteroids that share similar orbital elements.
Naming
Excerpted from Wikipedia’s “90 Antiope” article, available under the CC BY-SA 4.0 licence.