12621 Alsufi, provisionally designated , is a carbonaceous Themistian
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 outer region 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 7 kilometers in diameter. It was discovered by astronomers during the
Palomar–Leiden survey
The Palomar–Leiden survey (PLS) was a successful astronomical survey to study faint minor planets in a collaboration between the U.S Palomar Observatory and the Dutch Leiden Observatory, and resulted in the discovery of thousands of asteroids, ...
in 1960, and named for medieval Persian astronomer
Abd al-Rahman al-Sufi
ʿAbd al-Rahman al-Sufi ( fa, عبدالرحمن صوفی; December 7, 903 – May 25, 986) was an iranianRobert Harry van Gent. Biography of al-Sūfī'. "The Persian astronomer Abū al-Husayn ‘Abd al-Rahmān ibn ‘Umar al-Sūfī was born in ...
.
Discovery
''Alsufi'' was discovered on 24 September 1960, by Dutch astronomer couple
Ingrid
Ingrid may refer to:
* Ingrid (given name)
* Ingrid (record label), and artist collective
* Ingrid Burley, rapper known mononymously as Ingrid
* Tropical Storm Ingrid, various cyclones
* 1026 Ingrid, an asteroid
* InGrid, the grid computing project ...
and
Cornelis van Houten
Cornelis Johannes van Houten (18 February 1920 – 24 August 2002) was a Dutch astronomer, sometimes referred to as Kees van Houten.
Early life and education
Born in The Hague, he spent his entire career at Leiden University except for a brief p ...
at Leiden, 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 Haa ...
at the U.S.
Palomar Observatory
Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...
, California. No
precoveries
In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens mos ...
were taken prior to its discovery observation.
Palomar–Leiden survey
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 ...
"P-L" stands for ''Palomar–Leiden'', named after Palomar Observatory and
Leiden Observatory
Leiden Observatory ( nl, Sterrewacht Leiden) is an astronomical institute of Leiden University, in the Netherlands. Established in 1633 to house the quadrant of Rudolph Snellius, it is the oldest operating university observatory in the world, with ...
, which collaborated on the fruitful
Palomar–Leiden survey
The Palomar–Leiden survey (PLS) was a successful astronomical survey to study faint minor planets in a collaboration between the U.S Palomar Observatory and the Dutch Leiden Observatory, and resulted in the discovery of thousands of asteroids, ...
in the 1960s. 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. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch (f/2.5) mirror. The instrument ...
(also known as the 48-inch Schmidt Telescope), and shipped the
photographic plate
Photographic plates preceded photographic film as a capture medium in photography, and were still used in some communities up until the late 20th century. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinn ...
s to Ingrid and Cornelis 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 celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
His ...
was carried out. The trio are credited with the discovery of several thousand minor planets.
Classification and orbit
It is a member of the
Themis family The Themis family (''adj. Themistian''; ) is a Asteroid family, family of carbonaceous asteroids located in the Kirkwood gap, outer portion of the asteroid belt, at a mean distance of 3.13 Astronomical Unit, AU from the Sun. It is one of the Asteroi ...
, a dynamical group of outer-belt asteroids with nearly coplanar ecliptical orbits. The
C-type asteroid
C-type (carbonaceous) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...
is also classified as a rather rare
L-type asteroid
L-type asteroids are relatively uncommon asteroids with a strongly reddish spectrum shortwards of 0.75 μm, and a featureless flat spectrum longwards of this. In comparison with the K-type, they exhibit a more reddish spectrum at visible wavele ...
by
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 ...