433 Eros
Six different views of Eros in approximate natural color from NEAR-Shoemaker in February 2000
|
|
| Discovery | |
|---|---|
| Discovered by | Carl Gustav Witt |
| Discovery date | August 13, 1898 |
| Designations | |
|
Named after
|
Eros |
| 1898 DQ; 1956 PC | |
| Amor I · Mars-crosser | |
| Adjectives | Erotian |
| Orbital characteristics | |
| Epoch October 22, 2004 (JD 2453300.5) | |
| Aphelion | 1.783 AU |
| Perihelion | 1.133 AU |
| 1.458 AU | |
| Eccentricity | 0.223 |
| 1.76 yr (643 days) | |
|
Average orbital speed
|
24.36 km/s |
| 320.215° | |
| Inclination | 10.829° |
| 304.401° | |
| 178.664° | |
| Earth MOID | 0.1492 AU |
| Physical characteristics | |
| Dimensions | 34.4×11.2×11.2 km 16.84 km (mean) |
| Mass | (6.687±0.003)×1015 kg |
|
Mean density
|
2.67±0.03 g/cm³ |
| 0.0059 m/s² | |
| 0.0103 km/s | |
| 0.2194 d (5 h 16 min) | |
| Albedo | 0.25 |
|
Spectral type
|
S |
| +7.0 to +15 | |
| 11.16 | |
433 Eros is an S-type near-Earth asteroid approximately 34.4×11.2×11.2 kilometres (21.4×7.0×7.0 mi) in size, the second-largest near-Earth asteroid after 1036 Ganymed. It was discovered in 1898 and was the first near-Earth asteroid discovered. It was the first asteroid orbited by an Earth probe (in 2000). It belongs to the Amor group.
Eros is a Mars-crosser asteroid, the first known to come within the orbit of Mars. Objects in such an orbit can remain there for only a few hundred million years before the orbit is perturbed by gravitational interactions. Dynamical integrations suggest that Eros may evolve into an Earth-crosser within as short an interval as two million years, and has a roughly 50% chance of doing so over a time scale of 108–109 years. It is a potential Earth impactor, about five times larger than the impactor that created Chicxulub crater and led to the extinction of the dinosaurs.
The NEAR Shoemaker probe visited Eros twice, first with a 1998 flyby, and then by orbiting it in 2000 when it extensively photographed its surface. On February 12, 2001, at the end of its mission, it landed on the asteroid's surface using its maneuvering jets.
Eros was discovered on 13 August 1898 by Gustav Witt in Berlin and Auguste Charlois at Nice. Witt was taking a 2-hour exposure of Beta Aquarii to secure astrometric positions of asteroid 185 Eunike.
During the opposition of 1900–1901, a worldwide program was launched to make parallax measurements of Eros to determine the solar parallax (or distance to the Sun), with the results published in 1910 by Arthur Hinks of Cambridge. A similar program was then carried out, during a closer approach, in 1930–1931 by Harold Spencer Jones. The value obtained by this program was considered definitive until 1968, when radar and dynamical parallax methods became more important.
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