960 Birgit ( ''prov. designation'': ''or'' ) is a background asteroid, approximately in diameter, located in the Florian region of the inner asteroid belt. It was discovered on 1 October 1921, by astronomer Karl Reinmuth at the Heidelberg Observatory in southern Germany. The possibly S-type asteroid has 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 8.9 hours. It was named after Birgit Asplind, daughter of Swedish astronomer

Bror Asplind Bror is a Scandinavian masculine given name which simply means 'brother'. The name has been found as early as in runestones in the form Brodhir. The name form Bror is known since the year 1536. It is also used heavily in a colloquial sense in the ci ...

(1890–1954).

Orbit and classification

Located in the Florian region, ''Birgit'' is a non-

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 ...

asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the inner asteroid belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,232 days; semi-major axis of 2.25 AU). Its orbit has an eccentricity of 0.17 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 3 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic agai ...

. The body's observation arc begins at Heidelberg on 25 October 1925, three weeks after its official discovery observation.

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 '' ...

was named after Birgit Asplind, daughter of Swedish astronomer

Bror Ansgar Asplind Bror is a Scandinavian masculine given name which simply means 'brother'. The name has been found as early as in runestones in the form Brodhir. The name form Bror is known since the year 1536. It is also used heavily in a colloquial sense in the ...

(1890–1954). Asteroids 958 Asplinda,

959 Arne 959 Arne ('' prov. designation:'' ''or'' ) is a background asteroid and slow rotator, approximately in diameter, located in the outer region of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg-Königstu ...

and 961 Gunnie are named after him and his other two children, respectively. The was mentioned in '' The Names of the Minor Planets'' by Paul Herget in 1955 ().

Physical characteristics

Based on its determined albedo, ''Birgit'' is an assumed S-type asteroid. The albedo determined by 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 2 ...

(WISE) for this asteroid agrees with that assumption ''(see below)''.

Rotation period

In February 2007, a rotational lightcurve of ''Birgit'' was obtained from photometric observations by Agnieszka Kryszczyńska at Poznań Observatory, Poland, and international collaborators. Lightcurve analysis gave a

of hours with a brightness variation of magnitude (). The result supersedes observations by Federico Manzini, Roberto Crippa, and Pierre Antonini from August 2005, who determined a poorly rated period of hours with an amplitude of magnitude ().

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's WISE telescope, ''Birgit'' measures kilometers in diameter and its surface has an albedo of . Another published measurement by the WISE team gives a mean-diameter of with an albedo of . The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for a stony asteroid of 0.20 and calculates a diameter of 9.40 kilometers based on an absolute magnitude of 12.5.

Notes

References

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External links

Lightcurve Database Query
(LCDB), at ''www.minorplanet.info''
Dictionary of Minor Planet Names
Google books

– '' Geneva Observatory'', Raoul Behrend
Discovery Circumstances: Numbered Minor Planets (1)-(5000)
– Minor Planet Center * * {{DEFAULTSORT:Birgit 000960 Discoveries by Karl Wilhelm Reinmuth Named minor planets 19211001