433 Eros

Eros (minor planet designation: (433) Eros), provisional designation 1898 DQ, is a stony asteroid of the Amor group and the first discovered and second-largest near-Earth object. It has an elongated shape and a volume-equivalent diameter of approximately 16.8 kilometers (10.4 miles). Visited by the NEAR Shoemaker space probe in 1998, it became the first asteroid ever studied from orbit around the asteroid. 
The asteroid was discovered by German astronomer C.G. Witt at the Berlin Observatory on 13 August 1898 in an eccentric orbit between Mars and Earth. It was later named after Eros, a god from Greek mythology, the son of Aphrodite. He is identified with the planet Venus.
== Discovery ==
Eros was discovered on 13 August 1898 by C.G. Witt at Berlin Urania Observatory and A. Charlois at Nice Observatory. Witt was taking a two-hour exposure of beta Aquarii to secure astrometric positions of asteroid 185 Eunike.
=== Name ===
Eros is named after the Greek god of love, Erōs. It is pronounced /ˈɛrɒs/ ERR-os or sometimes /ˈɪərɒs/ EER-os. The rarely used adjectival form of the name is Erotian /ɪˈroʊʃən/.
Eros was the first minor planet to be given a male name, on account of its orbit (it was the first near-Earth asteroid discovered).
=== Later studies ===
During the approach (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 A. Hinks of Cambridge and C.D. Perrine of the Lick Observatory, University of California. Perrine published progress reports in 1906 and 1908. He took 965 photographs with the Crossley Reflector and selected 525 for measurement. A similar program was then carried out, during a closer approach, in 1930–1931 by H.S. Jones. The value of the Astronomical Unit (roughly the Earth-Sun distance) obtained by this program was considered definitive until 1968, when radar and dynamical parallax methods started producing more precise measurements.
Eros was the first asteroid detected by the Arecibo Observatory's radar system.
Eros was one of the first asteroids visited by a spacecraft, the first one orbited, and the first one soft-landed on. NASA spacecraft NEAR Shoemaker entered orbit around Eros in 2000, and landed in 2001.
== Mars-crosser ==
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 non-avian dinosaurs.
== NEAR Shoemaker survey and landing ==
The NEAR Shoemaker probe visited Eros twice, first with a brief flyby in 1998, and then by orbiting it in 2000, when it extensively photographed its surface. On 12 February 2001, at the end of its mission, it landed on the asteroid's surface using its maneuvering jets.
This was the first time a Near Earth asteroid was closely visited by a spacecraft.
Category:Asteroids
Category:S type
Category:Mars-Crosser
Category:Amor
Category:Near Earth Object
Category:Geoasteroid
Category:Objects Not in Hydrostatic Equilibrium
Category:Objects with No Atmosphere
Category:Inner Solar System Object
Category:Numbered Objects
Category:Numbered Minor Planets
Category:Named Objects
Category:Named Minor Planets
Category:Objects Visited by Spacecraft