433 Eros

Encyclopedia : 4 : 43 : 433 : 433 Eros

**433 Eros**
Orbital elements
Eccentricity (orbit)>e
Inclination>i	°
Perihelion>q	~ on } Astronomical Unit>AU
Argument of perihelion>ω	°
Semi-major axis>a	AU
Longitude of the ascending node>ω	°
Aphelion>Q	~ on } Astronomical Unit>AU
Mean anomaly>M	°
Orbital period>P	years
Mean motion>n	°/day
Time of perihelion passage>TP

The asteroid 433 Eros (eer'-os) 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, belonging to the Amors. It is also a Mars-crosser asteroid.

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

Contents

1 Physical characteristics
2 Legal controversy
3 Aspects
4 Eros in fiction
5 See also
6 References
7 External links

Physical characteristics

Surface gravity depends on the distance from a spot on the surface to the center of a body's mass. The Erotian surface gravity varies a lot, since Eros 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. This impact may also be responsible for the 40 percent of the Erotian surface that is devoid of craters smaller than 0.5 kilometers across. It was originally thought that the debris thrown up by the collision filled in the smaller craters. An analysis of crater densities over the surface indicates that the areas with lower crater density are within 9 kilometers of the impact point. Some of the lower density areas were found on the opposite side of the asteroid but still within 9 kilometers.

It is theorized that seismic shockwaves propagated through the asteroid, shaking smaller craters into rubble. Since Eros is irregularly shaped, a 9 kilometer straight line through the asteroid can reach locations that would be further away if travelling across the surface, thus leading to the uneven pattern of crater density on the surface. (Thomas & Robinson, 2005)

Legal controversy

In an experimental legal case, Eros was claimed as property by Gregory W. Nemitz of OrbDev. According to the Homestead principle, Nemitz argued that he had the right to claim ownership of any celestial body that he made use of; he claimed he had designated Eros a spacecraft parking facility and wished to charge NASA a parking and storage fee of 20 cents per year for NEAR Shoemaker. Nemitz's case was dismissed and an appeal denied. [link]

Aspects

! Stationary, retrograde

Opposition	Opposition distance	Maximum brightness	Stationary, prograde	Conjunction to sun
16 April, 2005	0.365 96 AU	10.5 mag	2 May, 2005	3 March, 2006
9 July, 2007	0.747 92 AU	12 mag	22 August, 2007	11 October, 2008
1 September, 2009	0.689 42 AU	11.9 mag	15 October, 2009	2 January, 2011
28 February, 2012	0.175 79 AU	8.5 mag	15 March, 2012	20 February, 2013
28 June, 2014	0.719 76 AU	12.0 mag	10 August, 2014	16 July, 2015
21 August, 2016	0.727 46 AU	12.0 mag	5 October, 2016	23 December, 2017
3 December, 2018	0.223 39 AU	9.3 mag	22 December, 2018	11 February, 2020

Eros in fiction

Eros is also mentioned in Orson Scott Card's novel Ender's Game (1985). It used to be an outpost for the aliens known as Formics who installed artificial gravity but was taken over by humans and a Command School was built there. This is where Ender was sent after he graduated from Battle School.

433 Eros also plays an important role in the future evolution of life on Earth in Stephen Baxter's novel Evolution (2003). Millions of years after being perturbed into a new orbit, the asteroid collides with Earth, bringing about another mass extinction. The micrometeoroid-ravaged shell of NEAR Shoemaker still stands on the surface of Eros until seconds before the impact.

References

PMID 16034412

External links

[NEAR Shoemaker spacecraft]
[NEAR image of the day archive]
[Movie: NEAR Shoemaker spacecraft landing]
[The Eros Project] (OrbDev's attempts at litigation over their property claim)

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