File:000116-asteroid_shape_model_(116)_Sirona.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
- Christian Heinrich Friedrich Peters
- Discovery date
- 8 September 1871
- Pronunciation
- / ˈ s ɪr oʊ n ə /
- Named after
- Đīrona
- Alternative designations
- A871 RA; 1954 UC 3 ;, 1998 EK 13 ; 1998 ES 21
- Minor planet category
- Main belt
- Observation arc
- 143.31 yr (52345 d)
- Aphelion
- 3.1616 AU (472.97 Gm )
- Perihelion
- 2.37322 AU (355.029 Gm)
- Semi major axis
- 2.76741 AU (413.999 Gm)
- Orbital period sidereal
- 4.60 yr (1681.5 d )
- Average orbital speed
- 17.81 km/s
- Mean anomaly
- 7.59231 °
- Mean motion
- 0° 12 50.724 / day
- Inclination
- 3.5635°
- Longitude of ascending node
- 63.724°
- Argument of perihelion
- 94.932°
- Earth moid
- 1.38451 AU (207.120 Gm)
via Wikipedia infobox
~1 min read
Encyclopedic overview
116 Sirona is a somewhat large and bright-colored main-belt asteroid that was discovered by the German-American astronomer C. H. F. Peters on September 8, 1871, and named after Sirona, the Celtic goddess of healing.
This body is orbiting the Sun with a period of 4.60 years and an eccentricity (ovalness) of 0.14. The orbital plane is inclined by 3.56° to the plane of the ecliptic. The cross-section diameter of this object is ~72 km. Photometric observations of this asteroid gave a light curve with a period of 12.028 hours and a brightness variation of 0.42 in magnitude. It has the spectrum of an S-type asteroid, suggesting a siliceous composition.
Excerpted from Wikipedia’s “116 Sirona” article, available under the CC BY-SA 4.0 licence.