8967 Calandra, provisional designation ', is a carbonaceous 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 outer 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 9 kilometers in diameter. It was discovered on 13 May 1971, by Dutch astronomer couple

Ingrid Ingrid may refer to: * Ingrid (given name), including a list of people and fictional characters * Ingrid Burley (born 1986), rapper known mononymously as Ingrid * Ingrid (record label), also an artist collective * Tropical Storm Ingrid, various cy ...

and Cornelis van Houten at Leiden Observatory, on photographic plates taken by Dutch–American astronomer

Tom Gehrels Anton M.J. "Tom" Gehrels (February 21, 1925 – July 11, 2011) was a Dutch–American astronomer, Professor of Planetary Sciences, and Astronomer at the University of Arizona, Tucson. Biography Youth and education Gehrels was born at Ha ...

at the

Palomar Observatory The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

in California. It is named after the corn bunting ''(Emberiza calandra)''.

Orbit and classification

''Calandra'' is a non-family asteroid from the main belt's background population. It orbits the Sun in the outer main-belt at a distance of 2.7–3.4 AU once every 5 years and 4 months (1,952 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-Centre (geometry), center, in geometry * Eccentricity (g ...

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

of 10 ° 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 ...

. No

precoveries In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of a celestial object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This ha ...

were taken prior to its discovery.

Survey designation

The

survey designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calcu ...

"T-1" stands for the first Palomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar and

Leiden Observatory Leiden Observatory () is an astronomical institute of Leiden University, in the Netherlands. Established in 1633 to house the quadrant of Willebrord Snellius, it is the oldest operating university observatory in the world, with the only older sti ...

in the 1960s and 1970s. Gehrels used Palomar's

Samuel Oschin telescope The Samuel Oschin telescope (), also called the Oschin Schmidt, is a Schmidt camera at the Palomar Observatory in northern San Diego County, California, United States. It consists of a Schmidt corrector plate and a (f/2.5) mirror. The instrumen ...

(also known as the 48-inch Schmidt Telescope), and shipped the

photographic plate Photographic plates preceded film as the primary medium for capturing images in photography. These plates, made of metal or glass and coated with a light-sensitive emulsion, were integral to early photographic processes such as heliography, d ...

s to Cornelis and Ingrid van Houten at Leiden Observatory where

astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, th ...

was carried out. The trio of astronomers are credited with the discovery of 4,620 minor planets.

Physical characteristics

Rotation period

A photometric

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 ...

of ''Calandra'' obtained at the

Palomar Transient Factory The Palomar Transient Factory (PTF, obs. code: I41), was an astronomical survey using a wide-field survey camera designed to search for optical transient and variable sources such as variable stars, supernovae, asteroids and comets. The projec ...

in California in 2011, gave 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 hours with a brightness variation of 0.58

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 survey carried out by the

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 of 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 ...

, ''Calandra'' measures 8.4 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 ...

of 0.17. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for carbonaceous asteroids of 0.057 and hence calculates a larger diameter of 10.2 kilometers with an absolute magnitude of 13.54.

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 ...

is named for the passerine bird, ''Miliaria calandra'' or ''Emberiza calandra'', also known as the corn bunting. It is listed as an endangered species on the ''European Red List of Birds''. The approved naming citation 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 2 February 1999 ().

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:Calandra 008967 Discoveries by Cornelis Johannes van Houten Discoveries by Ingrid van Houten-Groeneveld Discoveries by Tom Gehrels 4878 Named minor planets 19710513