1313 Berna, provisional designation , is a background

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 ...

and synchronous

binary system A binary system is a system of two astronomical bodies of the same kind that are comparable in size. Definitions vary, but typically require the center of mass to be located outside of either object. (See animated examples.) The most common ki ...

from the Eunomian region in the central

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 ...

, approximately in diameter. It was discovered on 24 August 1933, by Belgian astronomer

Sylvain Arend Sylvain Julien Victor Arend (6 August 1902 – 18 February 1992) was a Belgian astronomer born in Robelmont, Luxembourg province, Belgium. His main interest was astrometry. Together with Georges Roland, he discovered the bright comet C/1956 ...

at the

Uccle Observatory The Royal Observatory of Belgium (; ; ) has been situated in the Uccle municipality of Brussels since 1890. It is part of the institutions of the Belgian Federal Science Policy Office (BELSPO). The Royal Observatory was first established in Sa ...

in Belgium. The assumed

S-type asteroid S-type (stony-type or silicaceous-type) asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are ...

has a longer-than average

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

of 25.5 hours and is likely elongated in shape. It was named for the Swiss capital of

Bern Bern (), or Berne (), ; ; ; . is the ''de facto'' Capital city, capital of Switzerland, referred to as the "federal city".; ; ; . According to the Swiss constitution, the Swiss Confederation intentionally has no "capital", but Bern has gov ...

. The discovery of an 11-kilometer-sized

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

was announced in February 2004.

Orbit and classification

According to modern HCM-analyses by Nesvorný, as well as by Milani and

Knežević Knežević () is a Serbian, Croatian, Montenegrin and Bosnian surname, derived from the title of '' knez''. It may refer to: * House of Knežević, Croatian noble family Knežević is the eighth most frequent surname in Croatia. The angliciz ...

, ''Berna'' is a non-

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 ...

asteroid from the main belt's background population. Based on osculating Keplerian

orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...

, it is located in the region of the

Eunomia family The Eunomia or Eunomian family () is a large asteroid family of S-type asteroids named after the asteroid 15 Eunomia. It is the most prominent family in the intermediate asteroid belt and the 6th-largest family with nearly six thousand known member ...

(), a prominent family of stony asteroids. It orbits the Sun in the central asteroid belt at a distance of 2.1–3.2 AU once every 4 years and 4 months (1,584 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 longe ...

of 2.66 AU). Its orbit has an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.21 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 reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 13 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

. In 1911, ''Berna'' was first identified as at

Johannesburg Johannesburg ( , , ; Zulu language, Zulu and Xhosa language, Xhosa: eGoli ) (colloquially known as Jozi, Joburg, Jo'burg or "The City of Gold") is the most populous city in South Africa. With 5,538,596 people in the City of Johannesburg alon ...

. Its

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 with its official discovery observation at Uccle.

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 after the Swiss capital city of

. The name was proposed by Sigmund Mauderli (1876–1962), astronomer and director of the Astronomical Institute at the

University of Bern The University of Bern (, , ) is a public university, public research university in the Switzerland, Swiss capital of Bern. It was founded in 1834. It is regulated and financed by the canton of Bern. It is a comprehensive university offering a br ...

, after whom

1748 Mauderli 1748 Mauderli, provisional designation , is a dark and very reddish Hildian asteroid from the outermost region of the asteroid belt, approximately 45 kilometers in diameter. It was discovered on 7 September 1966, by astronomer Paul Wild at Zim ...

is named. He computed the definitive orbit of the body, and also insisted to rename the minor planet to its current name, after it had been originally published as "Bernia". The official was first mentioned in ''

The Names of the Minor Planets Paul Herget (January 30, 1908 – August 27, 1981) was an American astronomer and director of the Cincinnati Observatory, who established the Minor Planet Center after World War II. Career Herget taught astronomy at the University of Cincinna ...

'' by

Paul Herget Paul Herget (January 30, 1908 – August 27, 1981) was an American astronomer and director of the Cincinnati Observatory, who established the Minor Planet Center after World War II. Career Herget taught astronomy at the University of Cincinna ...

in 1955 ().

Physical characteristics

Lightcurve

A network of astronomers at several observatories including

Raoul Behrend This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 nu ...

Geneva Observatory The Geneva Observatory (, ) is an astronomical observatory at Sauverny (CH) in the municipality of Versoix, Canton of Geneva, in Switzerland. It shares its buildings with the astronomy department of the École Polytechnique Fédérale de Lausann ...

, Switzerland, obtained the so-far best rated rotational

light-curve In astronomy, a light curve is a graph of the light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the ''y''-axis and with time on the ''x''-axis. The light is usually in a par ...

of ''Berna''. Light-curve analysis gave a

of hours with a brightness variation of 0.28

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

(). In November 2007, photometric observations at Cerro Tololo, Chile, using its 0.9-meter Prompt5 telescope in combination with the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003, that was deactivated when operations ended on 30 January 2020. Spitzer was the third space telescope dedicate ...

gave a concurring period of 25.46 hours with an amplitude of 0.5 magnitude (). Other light-curves were also obtained by several amateur astronomers giving a period of 6, 25.4 and 25.45 hours, respectively ().

Satellite

In February 2004, a satellite orbiting the asteroid was discovered. The moon, which does not have a provisional designation, measures about 11 kilometers in diameter and orbits ''Berna'' at a distance of 35 kilometer once every 25 hours and 28 minutes. Since the lightcurve is synchronized with the eclipse events, at least one body of the binary system rotates synchronously with the orbital motion. It was identified based on

observations taken in February 2004 by several astronomers, including Raoul Behrend at Geneva Observatory,

Stefano Sposetti Stefano Sposetti (born 22 December 1958) is a Swiss amateur astronomer and a prolific discoverer of minor planets. He lives in Gnosca, in the Italian-speaking part of Switzerland in the Ticino Alps, where the Gnosca Observatory is located. S ...

, René Roy, Donald Pray, Christophe Demeautis, Daniel Matter,

Alain Klotz This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 num ...

and others. Although the IAUC was released on 23 February 2004, the announcement was already made on 12 February 2004. There are several hundreds of asteroids known to have satellites ''(also see :Binary asteroids)''.

Diameter and albedo

According to the surveys carried out by the Japanese

Akari AKARI (ASTRO-F) was an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 UTC (06:28, 22 February JST) by M-V rocket ...

satellite, NASA's Spitzer Space Telescope and the

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, List of observatory codes, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy Space observatory, space telescope in the Explorers Program launched in December 2009.. . WISE L ...

with its subsequent

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy space telescope in the Explorers Program launched in December 2009.. . WISE discovered thousands of minor planets and nu ...

mission, ''Berna'' measures between 13.12 and 19.96 kilometers in diameter and its surface has an

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

between 0.13 and 0.25. The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.21 – derived from

15 Eunomia 15 Eunomia is a very large asteroid in the middle asteroid belt. It is the largest of the stony ( S-type) asteroids, with 3 Juno as a close second. It is quite a massive asteroid, in 6th to 8th place (to within measurement uncertainties). It is ...

, the parent body of the Eunomia family – and calculates a diameter of 13.88 kilometers based on an absolute magnitude of 11.6.

Orbit and classification

Naming

Physical characteristics

Lightcurve

Satellite

Diameter and albedo

Notes

References

External links