File:132Aethra_(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
- James C. Watson
- Discovery site
- Angell Hall Observatory
- Discovery date
- 13 June 1873
- Pronunciation
- / ˈ iː θ r ə /
- Named after
- Aethra
- Alternative designations
- A873 LA · A922 XB · 1949 MD · 1953 LF
- Minor planet category
- Mars crosser
- Observation arc
- 152.30 yr (55628 d)
- Aphelion
- 3.6230 AU (541.99 Gm )
- Perihelion
- 1.6012 AU (239.54 Gm)
- Semi major axis
- 2.6121 AU (390.76 Gm)
- Orbital period sidereal
- 4.2217 yr (1541.9 d )
- Average orbital speed
- 17.72 km/s
- Mean anomaly
- 113.0611°
- Mean motion
- 0° 14 0.24 / day
- Inclination
- 24.9835°
- Longitude of ascending node
- 258.0509°
- Argument of perihelion
- 255.6188°
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Aethra
- Followed by
- 133 Cyrene
- Follows
- 131 Vala
- Parent body
- Sun
- Minor-planet group
- Mars-crossing asteroid
- Diameter
- 42.87
- Orbital period
- 1541.978876415108
- Image
- 132Aethra (Lightcurve Inversion).png
Show 19 more facts
- discoverer or inventor
- James Craig Watson
- site of astronomical discovery
- Detroit Observatory
- provisional designation
- A873 LA
- time of discovery or invention
- 1873-06-13
- asteroid spectral type
- X-type asteroid
- orbital inclination
- 24.98354039991768
- albedo
- 0.199
- Commons category
- 132 Aethra
- rotation period
- 5.1684
- absolute magnitude
- 8.96
- orbital eccentricity
- 0.3870076225195472
- semi-major axis of an orbit
- 2.612081149208634
- periapsis
- 1.601185833825274
- apoapsis
- 3.622976464591994
- longitude of ascending node
- 258.050851711572
- argument of periapsis
- 255.6188464427536
- mean anomaly
- 113.0611629144905
- time of periapsis
- 2460516.2279862305
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~5 min read
Encyclopedic overview
132 Aethra is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It was discovered by James Craig Watson on 13 June 1873 at Angell Hall Observatory in Ann Arbor, Michigan. It is the first Mars-crossing asteroid to be identified. It subsequently became a lost asteroid, and was only rediscovered in December 1922. It is named after Aethra, the mother of Theseus in Greek mythology.
Aethra measures approximately 43–44 kilometers in diameter and has a rotation period slightly longer than five hours. It is the largest and brightest of the Mars-crossers and is classified as an M-type asteroid under the Tholen classification scheme. Its surface is relatively reflective and is likely composed of various silicate, hydroxide, and iron-bearing minerals.
Excerpted from Wikipedia’s “132 Aethra” article, available under the CC BY-SA 4.0 licence.