1405 Sibelius, provisional designation , is a stony Florian

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 inner regions of the

asteroid 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 ...

, approximately 8 kilometers in diameter. It was discovered on 12 September 1936, by Finnish astronomer

Yrjö Väisälä Yrjö Väisälä (; 6 September 1891 – 21 July 1971) was a Finnish astronomer and physicist. His main contributions were in the field of optics. He was also active in geodetics, astronomy and optical metrology. He had an affectionate nick ...

Turku Observatory Turku ( ; ; sv, Åbo, ) is a city and former capital on the southwest coast of Finland at the mouth of the Aura River, in the region of Finland Proper (''Varsinais-Suomi'') and the former Turku and Pori Province (''Turun ja Porin lääni''; ...

in Southwest Finland. The asteroid was named after composer

Jean Sibelius Jean Sibelius ( ; ; born Johan Julius Christian Sibelius; 8 December 186520 September 1957) was a Finnish composer of the late Romantic and 20th-century classical music, early-modern periods. He is widely regarded as his country's greatest com ...

Orbit and classification

''Sibelius'' is a member of the

Flora family The Flora family (''adj. Florian''; ; also known as ''Ariadne family'') is a prominent family of stony asteroids located in the inner region of the asteroid belt. It is one of the largest families with more than 13,000 known members, or approx ...

, one of the largest populations of stony asteroids in the entire main-belt. It orbits the Sun in the

inner Interior may refer to: Arts and media * ''Interior'' (Degas) (also known as ''The Rape''), painting by Edgar Degas * ''Interior'' (play), 1895 play by Belgian playwright Maurice Maeterlinck * ''The Interior'' (novel), by Lisa See * Interior de ...

main-belt at a distance of 1.9–2.6 AU once every 3 years and 5 months (1,234 days). 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-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.15 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 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 again ...

. 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 with an observation taken at Turku two weeks prior to its official discovery observation.

Physical characteristics

''Sibelius'' has been characterized as an

S-type asteroid S-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 of this type, making it the second ...

Pan-STARRS The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical c ...

photometric survey.

Rotation period

In October 2007, a rotational

lightcurve In astronomy, a light curve is a graph of 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 particular frequ ...

of ''Sibelius'' was obtained from photometric observations taken by

Petr Pravec Petr Pravec (born September 17, 1967) is a Czech astronomer and a discoverer of minor planets, born in Třinec, Czech Republic. Pravec is a prolific discoverer of binary asteroids, expert in photometric observations and rotational lightcurves a ...

at the

Ondřejov Observatory The Ondřejov Observatory (; cs, Observatoř Ondřejov) is the principal observatory of the Astronomical Institute () of the Academy of Sciences of the Czech Republic. It is located near the village of Ondřejov, southeast of Prague, Czech R ...

in the Czech Republic. Lightcurve analysis 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 6.051 hours with a brightness variation of 0.11

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 ...

().

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 ...

and NASA's

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) with its subsequent

NEOWISE 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, ...

mission, ''Sibelius'' measures between 6.21 and 12.18 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 0.14 and 0.48. The ''Collaborative Asteroid Lightcurve Link'' adopts an albedo of 0.3191 and a diameter of 7.20 kilometers from Petr Pravec's revised WISE thermal observations.

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

(1865–1957), Finnish violinist and composer of the late Romantic and early-modern periods. 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. Function ...

on 20 February 1976 ().

Notes

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:Sibelius 001405 Discoveries by Yrjö Väisälä Named minor planets 19360912