1680 Per Brahe, provisional designation , is a bright 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 ...

from the central region of the

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 12 February 1942, by Finnish astronomer

Liisi Oterma Liisi Oterma (; 6 January 1915 – 4 April 2001) was a Finnish astronomer, the first woman to get a Ph.D. degree in astronomy in Finland. She studied mathematics and astronomy at the University of Turku, and soon became Yrjö Väisälä's assi ...

Turku Observatory Turku ( ; ; , ) is a city in Finland and the regional capital of Southwest Finland. It is located on the southwestern coast of the country at the mouth of the Aura River (Finland), River Aura. The population of Turku is approximately , while t ...

in Southwest Finland. The stony

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

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 3.4 hours. It is named after Swedish count and governor

Per Brahe the Younger Count Per Brahe the Younger (18 February 1602 – 12 September 1680) was a Swedish soldier, statesman, and author. He served as Privy Councillor from 1630, Lord High Steward from 1640, as well as Governor-General of Finland in 1637–1640 and ...

Orbit and classification

The

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 of the main belt's background population. It orbits the Sun in the central main-belt at a distance of 2.2–3.2 AU once every 4 years and 6 months (1,643 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 2.73 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 0.18 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 4 ° 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 ...

. ''Per Brahe'' was first identified as at

Heidelberg Observatory Heidelberg (; ; ) is the List of cities in Baden-Württemberg by population, fifth-largest city in the States of Germany, German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of studen ...

in 1902, extending the asteroid'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 ...

by 40 years prior to 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 ''minor ...

was named for Swedish count Per Brahe (1602–1680), who was

Governor General Governor-general (plural governors-general), or governor general (plural governors general), is the title of an official, most prominently associated with the British Empire. In the context of the governors-general and former British colonies, ...

of Finland in the 17th century. His prosperous legacy saw the establishment of Academia Aboensis, the first university in Finland, the construction of various new towns and many schools, and the publication of the first Finnish Bible. The official was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...

on 1 April 1980 ().

Physical characteristics

Lightcurve

In December 2012, two rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

s of ''Per Brahe'' were obtained by American astronomers

Robert Stephens Sir Robert Graham Stephens (14 July 193112 November 1995) was an English actor in the early years of Britain's Royal National Theatre. Early life Stephens was born in Shirehampton, Bristol, in 1931, the eldest of three children of shipyard ...

and Brian Warner. They gave a well-defined

of 3.426 and 3.428 hours with a brightness variation of 0.13 and 0.017

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 ...

, respectively (). Previously, lightcurves obtained by

Laurent Bernasconi 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 object, near-Earth and main-belt asteroids, Jupiter trojans and Distant minor planet, distant ob ...

and René Roy in 2005 and 2006, gave a similar period of 3.444 and 3.44 hours, respectively.().

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite

IRAS The Infrared Astronomical Satellite (Dutch language, Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a astronomical survey, survey of the entire night sky at infrared wavelengths. Launched on 25 Janu ...

, 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, and NASA's

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, ''Per Brahe'' measures between 13.96 and 18.29 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 0.178 and 0.300. The ''Collaborative Asteroid Lightcurve Link'' derives a higher albedo of 0.341 and a diameter of 14.36 kilometers with an absolute magnitude of 11.0.

References

External links

Lightcurve plot of 1680 Per Brahe
Palmer Divide Observatory, '' B. D. Warner'' (2012)
Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Per Brahe 001680 Discoveries by Liisi Oterma Named minor planets 001680 19420212