File:308_Polyxo_Orbit_Diagram.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
- Alphonse Borrelly
- Discovery date
- 31 March 1891
- Pronunciation
- / p ə ˈ l ɪ k s oʊ /
- Named after
- Πολυξώ Polyxō
- Minor planet category
- Main belt
- Adjectives
- Polyxoian / p ɒ l ɪ k ˈ s oʊ i ə n /
- Observation arc
- 124.63 yr (45,521 d)
- Aphelion
- 2.860 AU (427.8 Gm )
- Perihelion
- 2.640 AU (394.9 Gm)
- Semi major axis
- 2.750 AU (411.4 Gm)
- Orbital period sidereal
- 4.56 yr (1,665.5 d)
- Mean anomaly
- 70.4189°
- Mean motion
- 0° 12 58.158 / day
- Inclination
- 4.36141°
- Longitude of ascending node
- 181.727°
- Argument of perihelion
- 115.501°
- Dimensions
- 140.69 ± 3.8 km , 130 km
- Synodic rotation period
- 12.031 ± 0.009 h (0.50129 ± 0.00038 d )
via Wikipedia infobox
Wikidata facts
- Diameter
- 128.578
- Orbital period
- 1664.518329170319
Show 15 more facts
- provisional designation
- A891 FA
- time of discovery or invention
- 1891-03-31
- orbital inclination
- 4.363294009394526
- Commons category
- 308 Polyxo
- albedo
- 0.047
- rotation period
- 12.031
- absolute magnitude
- 8.17
- orbital eccentricity
- 0.03837970029207367
- semi-major axis of an orbit
- 2.748696376806061
- periapsis
- 2.643202233670335
- apoapsis
- 2.854190519941786
- longitude of ascending node
- 181.579015226448
- argument of periapsis
- 111.9383275532771
- mean anomaly
- 89.10625304540284
- time of periapsis
- 2460588.5028015617
Sources (2)
via Wikidata · CC0
~1 min read
Article
308 Polyxo is a main-belt asteroid that was discovered by Alphonse Borrelly on 31 March 1891, in Marseille. It is orbiting the Sun at a distance of 2.75 AU with a low orbital eccentricity (ovalness) of 0.04 and a period of 4.56 yr. The orbital plane is tilted at an angle of 4.36° to the plane of the ecliptic.
308 Polyxo is classified as a rare T-type asteroid, with a spectrum that bears some similarity to the Tagish Lake meteorite. A spectral feature at a wavelength of 3.0 μm suggests aqueous alteration of some surface materials. Photometric measurements reported in 1983 give a rotation period of 12.03 hours and a brightness variation of 0.20 in magnitude. The adaptive optics instrument at the W. M. Keck Observatory shows an oblate object with a diameter of 130 km. The size ratio between the major and minor axes is 1.26 ± 0.11. Light curves for this object suggests it has a very irregular shape.