418 Alemannia, provisional designation , is a metallic background

asteroid An asteroid is a minor planet of the 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 or icy bodies with no atmosphere. ...

from the central region of the asteroid belt, approximately 35 kilometers in diameter. It was discovered by German astronomer

Max Wolf Maximilian Franz Joseph Cornelius Wolf (21 June 1863 – 3 October 1932) was a German astronomer and a pioneer in the field of astrophotography. He was the chairman of astronomy at the University of Heidelberg and director of the Heidelberg-K� ...

Heidelberg Observatory Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. ...

in southern Germany on 7 September 1896 and named for the

student fraternity Fraternities and sororities are social organizations at colleges and universities in North America. Generally, membership in a fraternity or sorority is obtained as an undergraduate student, but continues thereafter for life. Some accept gradua ...

''Alemannia'' in

Heidelberg Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914 ...

Orbit and classification

''Alemannia'' is a non-

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

asteroid from the main belt's background population. It orbits the Sun in the intermediate main-belt at a distance of 2.3–2.9 AU once every 4 years and 2 months (1,525 days;

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...

of 2.59 AU). Its orbit has an eccentricity of 0.12 and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 7 ° with respect to the ecliptic. The body's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

begins at Heidelberg in December 1905, more than 9 years after its official discovery observation.

Physical characteristics

In the Tholen classification, ''Alemannia'' is a metallic M-type asteroid. The

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

(WISE) also characterized it as an M-type.

Rotation period

The best-rated photometric lightcurve observations gave a

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 4.671 hours with a brightness amplitude between 0.20 and 0.33 magnitude (), superseding previous observations that gave a period of 5.82 and 4.68 hours, respectively.

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite

IRAS The Infrared Astronomical Satellite (Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten mo ...

, the Japanese Akari satellite and the NEOWISE mission of NASA's WISE telescope, ''Alemannia'' measures between 32.98 and 45.448 kilometers in diameter and its surface has an

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

between 0.1057 and 0.201. The ''Collaborative Asteroid Lightcurve Link'' adopts the results obtained by IRAS, that is, an albedo of 0.1878 and a diameter of 34.1 kilometers based on an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of 9.77.

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named for the

''Alemannia'' in Heidelberg, Germany. It was named by German astronomer

Adolf Berberich Adolf Joseph Berberich (16 November 1861 – 27 April 1920) was a German astronomer best known for his work on calculating the orbits of minor planets and double stars. The minor planet 776 Berbericia was named in his honour. Early life Adol ...

(1861–1920) in 1901. The official naming citation was mentioned in '' The Names of the Minor Planets'' by Paul Herget in 1955 ().

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Alemannia 000418 Discoveries by Max Wolf Named minor planets 000418 18960907