File:31_Euphrosyne_VLT_(2021),_deconvolved.pdf · 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
- J. Ferguson
- Discovery date
- September 1, 1854
- Pronunciation
- / j uː ˈ f r ɒ s ɪ n iː /
- Named after
- Εὐφροσύνη Eyphrosynē
- Alternative designations
- A907 GP; A918 GB
- Minor planet category
- Main belt
- Adjectives
- Euphrosynean / j uː f r ɒ s ɪ ˈ n iː ə n /
- Aphelion
- 3.8523 AU, (576.296 million km)
- Perihelion
- 2.4585 AU, (367.786 million km)
- Semi major axis
- 3.1554 AU , (472.041 million km)
- Orbital period sidereal
- 5.61 yr (2041.585 d)
- Mean anomaly
- 87.1671°
- Inclination
- 26.3033°
- Longitude of ascending node
- 31.1186°
- Argument of perihelion
- 61.4704°
- Dimensions
- ( 294 ± 6 ) × ( 280 ± 10 ) × ( 248 ± 6 ) km
- Mean diameter
- 268 ± 4 km , 267.1 ± 2.6 km ( IRAS ) , 268 ± 6 km
- Mass
- (16.5 ± 2.6) × 10 kg , (17 ± 3) × 10 kg
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Euphrosyne
- Followed by
- 32 Pomona
- Follows
- 30 Urania
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 267.08
- Orbital period
- 2053.238019352748
- Image
- 31 Euphrosyne VLT (2021), deconvolved.pdf
Show 22 more facts
- discoverer or inventor
- James Ferguson
- site of astronomical discovery
- Old Naval Observatory
- provisional designation
- A854 RA
- time of discovery or invention
- 1854-09-01
- asteroid spectral type
- C-type asteroid
- orbital inclination
- 26.31223533623652
- albedo
- 0.053
- Commons category
- 31 Euphrosyne
- rotation period
- 5.53
- flattening
- 0.14
- density
- 1.66
- angular diameter
- 0.17
- absolute magnitude
- 6.81
- orbital eccentricity
- 0.2159206687414699
- semi-major axis of an orbit
- 3.161505296186658
- periapsis
- 2.478870958404336
- apoapsis
- 3.84413963396898
- longitude of ascending node
- 30.79587825196449
- argument of periapsis
- 61.97076102676407
- mean anomaly
- 147.893122366348
- time of periapsis
- 2460157.000606546
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~3 min read
Encyclopedic overview
31 Euphrosyne is one of the largest asteroids (approximately tied for 7th place, to within measurement uncertainties). It was discovered by James Ferguson on September 1, 1854, the first asteroid found from North America. It is named after Euphrosyne, one of the Charites in Greek mythology. In 2019 a small companion was discovered. It is the third-roundest known asteroid (after 1 Ceres and 10 Hygiea); this is thought to be due to having re-accreted after being disrupted by a collision, and it is not close to hydrostatic equilibrium.
Observations
Excerpted from Wikipedia’s “31 Euphrosyne” article, available under the CC BY-SA 4.0 licence.