(22) Kalliope I Linus is an asteroid moon that orbits the large

M-type asteroid M-type (aka M-class) asteroids are a spectral class of asteroids which appear to contain higher concentrations of metal phases (e.g. iron-nickel) than other asteroid classes, and are widely thought to be the source of iron meteorites. Definition ...

22 Kalliope. It was discovered on August 29, 2001, by

astronomers An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either obse ...

Jean-Luc Margot Jean-Luc Margot (born 1969) is a Belgian-born astronomer and a UCLA professor who specializes in planetary sciences. Career Margot has discovered and studied several binary asteroids with radar and optical telescopes. His discoveries include ( ...

and

Michael E. Brown Michael E. Brown (born June 5, 1965) is an American astronomer, who has been professor of planetary astronomy at the California Institute of Technology (Caltech) since 2003. His team has discovered many trans-Neptunian objects (TNOs), including ...

with the

Keck telescope The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state In the United States, a state is a constituent political entit ...

, in

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

. Another team also detected the moon with the Canada-France-Hawaii Telescope on September 2, 2001. Both telescopes are on Mauna Kea. It received the

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been cal ...

S/2001 (22) 1, until it was named. The naming proposal appeared in the discovery paper and was approved by the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

in July 2003. Although the naming proposal referred to the mythological

Linus Linus, a male given name, is the Latin form of the Greek name ''Linos''. It's a common given name in Sweden. The origin of the name is unknown although the name appears in antiquity both as a musician who taught Apollo and as a son of Apollo who di ...

, son of the muse

Calliope In Greek mythology, Calliope ( ; grc, Καλλιόπη, Kalliópē, beautiful-voiced) is the Muse who presides over eloquence and epic poetry; so called from the ecstatic harmony of her voice. Hesiod and Ovid called her the "Chief of all Muse ...

and the inventor of melody and rhythm, the name was also meant to honor

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and, historically, the lead developer of the Linux kernel, used by Linux distributions and other operating systems such as Android. He also ...

, inventor of the

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

operating system kernel, and Linus van Pelt, a character in the ''

Peanuts ''Peanuts'' is a syndicated daily and Sunday American comic strip written and illustrated by Charles M. Schulz. The strip's original run extended from 1950 to 2000, continuing in reruns afterward. ''Peanuts'' is among the most popular and infl ...

'' comic strip. With an estimated (17 ± 1 mi) diameter, Linus is very large compared to most asteroid moons, and would be a sizable asteroid by itself. The only known larger moons in the

main 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 ...

are the smaller components of the double asteroids 617 Patroclus and

90 Antiope Antiope ( minor planet designation: 90 Antiope) is a double asteroid in the outer asteroid belt. It was discovered on October 1, 1866, by Robert Luther. In 2000, it was found to consist of two almost-equally-sized bodies orbiting each other. At ...

. It has been estimated that Linus' orbit precesses at quite a rapid rate, making one cycle in several years. This is attributed primarily to the non-spherical shape of Kalliope. Linus's brightness has varied appreciably between observations, which may indicate that its shape is elongated. Linus may have formed out of

impact Impact may refer to: * Impact (mechanics), a high force or shock (mechanics) over a short time period * Impact, Texas, a town in Taylor County, Texas, US Science and technology * Impact crater, a meteor crater caused by an impact event * Impac ...

ejecta from a

collision In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great fo ...

with Kalliope, or a fragment captured after disruption of a parent asteroid (a proto-Kalliope).

References

External links

IAUC 7703: S/2001 (22) 1
announcing Linus' discovery (2001 September 3)

announcing Linus' naming (2003 August 8)

* ttps://web.archive.org/web/20060128034217/http://astron.berkeley.edu/~fmarchis/Science/Asteroids/#Kalliope Kalliope and Linusvery well resolved with the 8m VLT
orbit diagram for Linus
{{Small Solar System bodies Asteroid satellites Discoveries by Michael E. Brown