Asteroid Specifics for NEAR Mission
Mathilda- Main Belt Asteroid 253
- orbit- 394,000,000 km from sun
- size- 59 x 47 km, 60 km diameter
- perihelion point- 1.94 AU
Discovered 1885 by Johann Palisa, named after his wife
Near flew by 27, June, 1997
- C-type asteroid à source of chondrite meteorites
- 5 craters larger than 20 km in diameter (but only little more than half of the asteroid has been seen)
- Density 1.4 gm/cm3 , probably very porous like Styrofoam
- Albedo- 4%
- Surface color uniform despite craters. Interior homogenous, pristine sample of early solar system
- Rotation rate very slow à 17.4 days
- Brightness about 1.5 or .5 magnitudes, depending on position
- Oblong irregular shape
- Semi-Major Axis 2.46 AU
- Eccentricity- 0.2652
- Orbital period 4.31 years
- Mass 1.033 x 1017 kg
Gaspra- Orbits near inner edge of Main Asteroid Belt, 951
- orbit- 330,000,000 km from the sun
- size- 19 x 12 x 11 km
Discovered by Grigoriy N. Neujamin in 1916, named after a Black Sea resort where it was discovered from.
Flown by on October 29, 1991 by Galileo
- S-type asteroid à composed of a mixture of rocky and metallic minerals, such as metal rich silicates and pure metal chunks.
- Gaspra covered with impact craters, and from the small craters on the surface, we can estimate that it is about 200-500 million years old.
- Member of the Flora family of asteroids
- Rotational period 7.04 hours
- Irregular shape
- Semi Major Axis 2.20997 AU
- Orbital Period – 3.9 years
- Density unknown
- Albedo- 22%
- Eccentricity - .017331
- Mass- 1.0 x 1016 kg
Ida- Main Belt Asteroid 243, Koronis family
- orbit 428,000,000 km from sun
- size- 58 x 23 km
Discovered by Johann Palisa 1884
Flown by Galileo spacecraft on August 28, 1993
Named after a nymph from Greek mythology, also a mountain in Crete
- S-type asteroid, though density is low.
- Semi Major Axis- 2.86108 AU
- Eccentricity 0.04616
- Orbital Period- 4.84 years
- Inclination- 1.13664 degrees
- Mass- 1 x 1017 kg
- Density- 2.5 g/cm3
- Rotation Period 4 hours 37 minutes
- Albedo 24 %
- Surface heavily cratered and thus apparently very old, estimates from the Koronis break up
- Contains some magnetic material, though not dense enough for iron
- Irregularly shaped
- One satellite- Dactyl
Dactyl- found by the Galileo probe, first ‘asteroid moon’
Discovered in 1993
Named derived from mythological beings said to live on Mount Ida
- size- 1.2 x 1.4 x 1.6 km
- orbit- 90 km from Ida
- density- approx 2.2 g/cm3
- orbital period- 1.54 days
Thought to have originated from asteroid Ida, though no true explanation has been found.
Eros- S-type asteroid 433 orbiting sun between earth and mars.
- orbit- 172,800,000 km from the sun
- size- 33 x 13 x 13 km (second largest near earth asteroid)
Discovered by Gustav Witt in 1898
Studied by Near Shoemaker probe on February 12, 2001
Named after Eros, the Greek god of love
- Mass- 7.2 x 1015 kg
- Density- 2.4 g/cm3
- Semi Major Axis- 1.45821 AU
- Orbital Period- 1.76 years
- Inclination- 10.82948 degrees
- Rotation Period- 5 hours and 16 minutes
- Albedo- 16%
- Daytime temperature- 100 degrees Celsius
- Nighttime temperature- -150 degrees Celsius
Near Shoemaker probe actually landed on Eros
- Surface heavily cratered
- One side dominated by a scallop-rimmed gauge opposite a sharp rimmed crater, resembles a ‘fat banana’.
- Due to odd shape, variable surface gravity
Works Cited:
http://www.nineplanets.org/nineplanets.html#toc
http://en.wikipedia.org/wiki/Main_Page
http://www.planetary.org/html/neo/Objects-Impacts/mathilda.html