File:106_Dione.png · Wikimedia Commons · See Wikimedia Commons
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
- James Craig Watson
- Discovery date
- 10 October 1868
- Pronunciation
- / d aɪ ˈ oʊ n iː /
- Named after
- Dione
- Alternative designations
- A868 TA, 1902 TA
- Minor planet category
- Main belt
- Observation arc
- 145.03 yr (52972 d)
- Aphelion
- 3.7032 AU (553.99 Gm )
- Perihelion
- 2.64584 AU (395.812 Gm)
- Semi major axis
- 3.17451 AU (474.900 Gm)
- Orbital period sidereal
- 5.66 yr (2065.9 d )
- Average orbital speed
- 16.61 km/s
- Mean anomaly
- 51.5257 °
- Mean motion
- 0° 10 27.336 / day
- Inclination
- 4.5972°
- Longitude of ascending node
- 62.163°
- Argument of perihelion
- 329.725°
- Earth moid
- 1.65175 AU (247.098 Gm)
via Wikipedia infobox
~2 min read
Encyclopedic overview
106 Dione is a large main-belt asteroid. It probably has a composition similar to 1 Ceres. It was discovered by J. C. Watson on October 10, 1868, and named after Dione, a Titaness in Greek mythology who was sometimes said to have been the mother of Aphrodite, the Greek goddess of love and beauty. It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter. The orbital period for this object is 5.66 years and it has an eccentricity of 0.17.
Measurements made with the IRAS observatory give a diameter of 169.92±7.86 km and a geometric albedo of 0.07±0.01. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 168.72±8.89 km and a geometric albedo of 0.07±0.01. Dione was observed to occult a dim star on January 19, 1983, by observers in Denmark, Germany and the Netherlands. A diameter of 147±3 km was deduced, closely matching the value acquired by the IRAS satellite. As of 2012, the mean diameter derived through occultation measurements is 176.7±0.4 km.
Excerpted from Wikipedia’s “106 Dione” article, available under the CC BY-SA 4.0 licence.