679 Pax

Also known as (679) Pax, Pax

main-belt asteroid

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

Small body data

679 Pax (A909 BR)

Orbit class: Main-belt Asteroid
Diameter: 63.909 km
Albedo: 0.110
Rotation period: 8.452 h
Absolute magnitude: 9.140 H
Earth MOID: 0.959 AU

via NASA/JPL Small-Body Database

Key facts

Discovered by: August Kopff
Discovery site: Heidelberg
Discovery date: 28 January 1909
Pronunciation: / ˈ p æ k s /
Alternative designations: 1909 FY
Observation arc: 106.90 yr (39044 d)
Aphelion: 3.3910 AU (507.29 Gm )
Perihelion: 1.7808 AU (266.40 Gm)
Semi major axis: 2.5859 AU (386.85 Gm)
Orbital period sidereal: 4.16 yr (1518.8 d )
Mean anomaly: 33.4022 °
Mean motion: 0° 14 13.272 / day
Inclination: 24.387°
Longitude of ascending node: 112.263°
Argument of perihelion: 266.736°
Mean radius: 25.735 ± 1.2 km , 32.44 ± 1.82 km
Mass: (7.14 ± 1.99) × 10 kg
Mean density: 4.99 ± 1.62 g/cm

via Wikipedia infobox

~2 min read

Encyclopedic overview

679 Pax is a minor planet orbiting the Sun that was discovered by German astronomer August Kopff on January 28, 1909. It is named after Pax, a Roman goddess. It is orbiting the Sun with a period of 4.16 years, a semimajor axis of 2.59 AU, and a moderately high eccentricity of 0.31. The last causes it to vary in distance from the Sun over the course of its orbit, ranging from 1.78 to 3.39 AU. The orbital plane is inclined at an angle of 24.4° relative to the plane of the ecliptic.

Measurements using the adaptive optics at the W. M. Keck Observatory give a mean diameter of 62 km. This is 16% larger than the diameter estimated using the IRAS observatory. The asteroid is elongated with a size ratio of 1.66 ± 0.23 between the major and minor axes. Photometric measurements reported in 1982 gave a rotation period of 8.452 hours. The asteroid's pole of rotation lies 32° away from the plane of the ecliptic.

Excerpted from Wikipedia’s “679 Pax” article, available under the CC BY-SA 4.0 licence.