The Themis family (''adj. Themistian''; ) is a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of carbonaceous
asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
s located in the
outer portion of the
asteroid belt
The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...
, at a mean distance of 3.13
AU from the
Sun. It is one of the
largest families with over 4700 known members,
and consists of a well-defined core of larger bodies surrounded by a region of smaller ones. The
collisional Themis family is named after its
parent body, the asteroid
24 Themis, discovered on 5 April 1853 by Italian astronomer
Annibale de Gasparis.
Description
The Themis family is one of the largest and longest-recognized dynamical families of asteroids, and is made up of
C-type asteroid
C-type (carbonaceous ) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...
s with a composition believed to be similar to that of
carbonaceous chondrites.
DIVERSITY OF TYPES OF HYDRATED MINERALS ON C≠CLASS ASTEROIDS
A. S. Rivkin, Massachusetts Institute of Technology, E. S. Howell, Arecibo Observatory, S. J. Bus, Institute for Astronomy To date, the Themis family comprises approximately 535 known asteroids.
Asteroids in the Themis family share the following orbital elements:
* semimajor axes between 3.08 AU and 3.24 AU
* orbital eccentricities between 0.09 and 0.22
* orbital inclinations of less than 3°
List
Some of the largest members of this family include:62 Erato
62 Erato () is a carbonaceous asteroid from the outer region of the asteroid belt, approximately in diameter. It is a member of the Themis family of asteroids that share similar properties and orbital characteristics. Photometry (astronomy), Ph ...
* 90 Antiope
* 104 Klymene
104 Klymene is a large, dark Themistian asteroid that was discovered by J. C. Watson on September 13, 1868, and named after one of the many Clymenes in Greek mythology. It is orbiting the Sun with a period of 5.60 years and an eccentricity ...
* 171 Ophelia
* 222 Lucia
* 223 Rosa
* 316 Goberta
* 379 Huenna
* 383 Janina
* 468 Lina
* 492 Gismonda
492 Gismonda is a main belt asteroid discovered by German astronomer Max Wolf in 1902. Gismonda is named after the daughter of Tancred, prince of Salerno, from Giovanni Boccaccio's work, The Decameron. It is orbiting from the Sun with a peri ...
* 515 Athalia
* 526 Jena
* 767 Bondia
* 846 Lipperta
See also
* Hirayama family
References
*
External links
Nesvorny HCM Asteroid Families V3.0
Small Bodies Data Ferret
{{Small Solar System bodies
*
Asteroid groups and families