253 Mathilde

253 Mathilde is a Mainbelt asteroid with a relatively small perihelion (1.94 AU)

        orbita: 394,000,000 km od planeta the Sun (average)
        size:  59 x 47 km

Mathilde was discovered v letu 1885 by Johann Palisa. The name is thought to honor the wife of astronomer Moritz Loewy, then the vice director of the Paris Observatory.

The spacecraft NEAR made a flyby of Mathilde on 27 June 1997; NEAR's Mainmission to orbita the asteroid 433 Eros.

The only other three asteroids that have been encountered by spacecraft 433 Eros, 243 Ida in Gaspra are S-type asteroids; Mathilde is our first look at a C-type. C-type asteroids are believed to be the source of carbonaceous chondrite meteorites.

Mathilde has at least 5 craters larger than 20 kilometers v letu premer (in we only got to see a little more than half its surface). Ida in Gaspra do not have such large craters. It is not clear how such large craters can be produced on such a small body.

Mathilde's density is only 1.4 gm/cm^3. It is probably very porous, somewhat like styrofoam. This may help account for the large craters.

It's albedo is only 4%. Furthermore, its surface color is very uniform despite the deep craters. This v letudicates that its v letuterior is homogeneous, perhaps a pristv letue sample of the early solar system.

Another oddity is that Mathilde's rotation rate is very slow, 17.4 dnevi. Perhaps this is somehow due to the many large impacts it obviously suffered.

More about Mathilde

more images
NEAR home page
Mathilde Encounter: June 27, 1997 od planeta John Hopkv letus Univ.
od planeta NSSDC
What is 253 Mathilde Like?, Lucy McFadden
more v letufo od planeta NSSDC
So many craters, so little asteroid (press release od planeta Cornell)

Open Issues

Is Mathilde typical of C-type asteroids?
How did it manage to be get such large craters without bev letug completely shattered?
How can we explav letu such a low density?