433 Eros

Discovery
Discoverer	Carl Gustav Witt
Discovery Date	August 13, 1898
Alternate Designations	1898 DQ; 1956 PC
Category	Near-Earth, Mars-crosser asteroid
Orbital Elements Epoch October 22, 2004 (JD 2453300.5)
Eccentricity (e)	0.223
Semi-Major Axis (a)	218.155 Gm (1.458 AU)
Perihelion (q)	169.548 Gm (1.133 AU)
Aphelion (Q)	266.762 Gm (1.783 AU)
Orbital Period (P)	643.219 d (1.76 a)
Mean Orbital Speed	24.36 km/s
Inclination (i)	10.829°
Longitude of the Ascending Node (Ω)	304.401°
Argument of Perihelion (ω)	178.664°
Mean Anomaly (M)	320.215°
Physical Characteristics
Dimensions	13×13×33 km
Mass	7.2×1015 kg
Density	2.4 g/cm³
Surface Gravity	0.0059 m/s²
Escape Velocity	0.0103 km/s
Rotation Period	0.2194 d (5 h 16 min)
Spectral Class	S
Absolute Magnitude	11.16
Albedo	0.16
Mean Surface Temperature	~312 K

The asteroid 433 Eros was named after the Greek god of love Eros. It is an S-type asteroid approximately 13 × 13 × 33 km in size, the second-largest near-Earth asteroid. It is also a Mars-crosser asteroid.

It was visited by the NEAR Shoemaker probe, which first orbited it taking extensive photographs of its surface and then on February 12th 2001 at the end of its mission was landed on the asteroid's surface using only its maneuvering jets.

Depending on where he stood on Eros, a person who weighed 890 newtons (200 pounds force) on Earth (note that we use a different meaning of "weight" in medicine and sports, using kilograms and pounds mass to measure this quantity which does not vary with local gravity) would weigh about 0.6 newton (two ounces-force) on the asteroid. A rock tossed from the asteroid's surface at 37 km/h (23 mph) could escape into space. A person with a 90 cm (36 inch) vertical leap could jump about 1.6 km (1 mile) on Eros and risk ending up in orbit.

Surface gravity depends on the distance from a spot on the surface to the center of a body's mass. The surface gravity on Eros varies a lot, since it is not a sphere but an elongated peanut-shaped (or potato- or shoe-shaped) object. The daytime temperature on Eros hovers at about 100 °C and nighttime measurements at −150 °C. Eros's density is 2,400 kg/m³, about the same as the density of Earth's crust. It rotates once every 5.27 hours.

NEAR scientists have found that most of the larger rocks strewn across Eros were ejected from a single crater in a meteorite collision perhaps 1 Ga (1 billion years) ago.

Eros is claimed as property by Gregory W. Nemitz of OrbDev . According to the Homestead principle, he wishes to charge NASA a parking and storage fee of 20 cents per year for the presence of NEAR Shoemaker on the asteroid. He is currently engaged in litigation to get his claim validated by the courts.

See also: List of geological features on 433 Eros

External links

• NEAR Shoemaker spacecraft http://near.jhuapl.edu/
• NEAR image of the day archive http://near.jhuapl.edu/iod/archive.html
• Movie: NEAR Shoemaker spacecraft landing http://near.jhuapl.edu/iod/20010731/index.html
• The Eros Project http://www.erosproject.com (OrbDev's attempts at litigation over their property claim)