The Themis family (''adj. Themistian''; ) is a
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of carbonaceous
asteroid
An asteroid is a minor planet of the Solar System#Inner solar system, inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic o ...
s located in the
outer portion of the
asteroid belt
The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...
, 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
In meteoritics, a parent body is the celestial body from which originates a meteorite or a class of meteorites.
Identification
The easiest way to correlate a meteorite with a parent body is when the parent body still exists. This is the case fo ...
, 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 chondrite
Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small prop ...
s.
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:24 Themis
Themis (minor planet designation: 24 Themis) is one of the largest asteroids in the asteroid belt. It is also the largest member of the Themistian family. It was discovered by Annibale de Gasparis on 5 April 1853. It is named after Themis, t ...
* 62 Erato
Erato (minor planet designation: 62 Erato) is a carbonaceous Themistian asteroid from the outer region of the asteroid belt, approximately in diameter. Photometric measurements during 2004–2005 showed a rotation period of with an amplitude ...
* 90 Antiope
* 104 Klymene
Klymene (minor planet designation: 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 ...
* 171 Ophelia
Ophelia (minor planet designation: 171 Ophelia) is a large, dark Themistian asteroid that was discovered by French astronomer Alphonse Borrelly on 13 January 1877, and named after Ophelia in Shakespeare's ''Hamlet''.
This asteroid is a member o ...
* 222 Lucia
Lucia (minor planet designation: 222 Lucia) is a large Themistian asteroid. It was discovered by Johann Palisa on 9 February 1882 in Vienna and named after Lucia, daughter of Austro-Hungarian
Austria-Hungary, often referred to as the Austr ...
* 223 Rosa
* 316 Goberta
* 379 Huenna
* 383 Janina
* 468 Lina
* 492 Gismonda
* 515 Athalia
* 526 Jena
* 767 Bondia
767 Bondia ('' prov. designation:'' ''or'' ) is a Themis asteroid from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 23 September 1913, by American astronomer Joel Hastings Metcalf at his observatory ...
* 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