|
Asteroids In The Solar System
Hundreds of thousands of asteroids
have been discovered within the solar system.
As of October 19, 2005, from a total of 299,733
minor planets with calculated orbits, 118,161
asteroids had been calculated well enough to be
given official numbers and 12,712 of these had
been officially given trivial names to go along
with the numbers (at least 610 of which have names
requiring diacritics). The lowest-numbered but
unnamed minor planet is (3360) 1981 VA; the highest-numbered
named minor planet is 99942 Apophis.
The Minor Planet Circular (MPC) of October
19, 2005 was a historical one, as it saw numbered
asteroids jump from 99947 to 118161, causing
a small "Y2k" like crisis for various
automated data services —up until then,
only five digits were allowed in most data
formats for the asteroid number. (This was
solved in some data fields by having the leftmost
digit, the ten-thousand places, use the alphabet
as a digit extension. A=10, B=11… Z=35,
a=36… z=61. The highest number 118161
thus is cross-referenced as B8161 on some
lists.) |
|
Current estimates put the total
number of asteroids in the solar system at several
million. The largest asteroid in the inner solar
system is 1 Ceres, with a diameter of 900-1000
km. Two other large inner solar system belt asteroids
are 2 Pallas and 4 Vesta; both have diameters
of ~500 km. Vesta is the only main belt asteroid
that is sometimes visible to the naked eye .The
mass of all the asteroids of the Main Belt is
estimated to be about 2.3x1021 kg, or about 3%
of the mass of our moon. Of this, 1 Ceres comprises
940 to 950x1018 kg, some 40% of the total. Adding
in the next three most massive asteroids, 4 Vesta
(12%), 2 Pallas (9%), and 10 Hygiea (4%), bring
this figure up 66%; while the three after that,
511 Davida (1.6%), 704 Interamnia (1.4%), and
3 Juno (1.2%), only add another 4% to the total
mass. The number of asteroids then increases exponentially
as their individual masses decrease.
Also see
vAsteroids
Exploration
vAsteroids
Discovery
vAsteroids
Classifications
|
