File:516Amherstia_(Lightcurve_Inversion).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
- Raymond Smith Dugan
- Discovery date
- 20 September 1903
- Named after
- Amherst College
- Alternative designations
- 1903 MG; 1938 YO
- Minor planet category
- Main belt
- Observation arc
- 112.26 yr (41003 d)
- Aphelion
- 3.4103 AU (510.17 Gm )
- Perihelion
- 1.95161 AU (291.957 Gm)
- Semi major axis
- 2.68094 AU (401.063 Gm)
- Orbital period sidereal
- 4.39 yr (1,603.4 d)
- Mean anomaly
- 26.3259 °
- Mean motion
- 0° 13 28.308 / day
- Inclination
- 12.960°
- Longitude of ascending node
- 328.839°
- Argument of perihelion
- 257.966°
- Mean diameter
- 65.144 ± 0.380 km , 41.9 ± 3.3 km
- Mass
- (4.7 ± 2.04/1.46) × 10 kg
- Mean density
- 3.246 ± 1.408/1.011 g/cm
via Wikipedia infobox
~1 min read
Encyclopedic overview
516 Amherstia was the 8th asteroid discovered by Raymond Smith Dugan, and was named after Amherst College, his alma mater. Amherstia is a large M-type main belt asteroid, with an estimated diameter of 73 km. It follows an eccentric orbit between Jupiter and Mars, with an orbital period of 4.39 years. The orbital plane is inclined at an angle of 13° to the ecliptic.
In 1989, the asteroid was observed from the Collurania-Teramo Observatory, allowing a light curve to be produced that showed an estimated rotation period of 7.49 hours and a brightness variation of 0.25 ± 0.01 in magnitude. On January 14, 2002, Amherstia was observed to occult the seventh-magnitude star SAO 60107 from ten sites in Florida. The measured timing chords were used to estimate a cross-section diameter of 41.9±3.3 km with a generally circular profile. The near infrared spectra of Amherstia suggests a surface consisting of a single mafic silicate with iron–nickel alloy. The infrared albedo is 16%.
Excerpted from Wikipedia’s “Q155060” article, available under the CC BY-SA 4.0 licence.