9175 Graun, provisional designation , is a stony Eunomian
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 central region of the
asteroid belt, approximately 10 kilometers in diameter. It was discovered on 29 July 1990, by American astronomer
Henry E. Holt at
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 ...
in California, United States.
The asteroid was later named for American author and amateur astronomer
Ken Graun
Ken or KEN may refer to:
Entertainment
* ''Ken'' (album), a 2017 album by Canadian indie rock band Destroyer.
* ''Ken'' (film), 1964 Japanese film.
* ''Ken'' (magazine), a large-format political magazine.
* Ken Masters, a main character in t ...
.
Orbit and classification
''Graun'' is a member of the
Eunomia family, a large group of
S-type asteroids and the most prominent family in the
intermediate main-belt. It orbits the Sun at a distance of 2.2–3.0
AU once every 4 years and 2 months (1,531 days). Its orbit has an
eccentricity of 0.14 and an
inclination of 15
° with respect to the
ecliptic.
In February 1975, it was first identified as at the
Karl Schwarzschild Observatory, extending the body's
observation arc by 15 years prior to its official discovery observation at Palomar.
Alternative family
Based on its concurring orbital elements, ''Graun'' has also been group into the
Maria family
The Maria family (adj. ''Marian''; FIN: 506; also known as ''Roma family'') is a collisional asteroid family located in the inner parts of the intermediate asteroid belt, near the 1:3 Kirkwood gap. The family consist of several thousand stony S-ty ...
, which is named after its namesake, the asteroid
170 Maria
Maria (minor planet designation: 170 Maria) is a Main belt asteroid that was discovered by French astronomer Henri Joseph Perrotin on January 10, 1877. Its orbit was computed by Antonio Abetti, and the asteroid was named after his sister, Maria ...
.
It is an old-type asteroid family, about years old, located near the area of a 3:1
resonances with Jupiter that supplies near-Earth asteroids to the inner
Solar System. It is estimated that every 100 million years, about 37 to 75 Maria asteroids larger than 1 kilometer become
near-Earth objects.
Physical characteristics
Lightcurves
In January 2013, a rotational
lightcurve of ''Graun'' was obtained from photometric observations. 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 hours with a brightness variation of 0.16
magnitude ().
The measurement supersedes a shorter period of 20 hours with an amplitude of 0.2 magnitude ().
Diameter and albedo
According to the surveys carried out by the
NEOWISE mission of NASA's
Wide-field Infrared Survey Explorer and the Japanese
Akari satellite, ''Graun'' measures 10.23 and 10.35 kilometers in diameter, and its surface has an
albedo of 0.20 and 0.183, respectively.
Preliminary NEOWISE results gave a much higher albedo and consequently shorter diameter.
The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.21 – derived from
15 Eunomia
Eunomia (minor planet designation 15 Eunomia) is a very large asteroid in the inner 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 ...
, the family's largest member and namesake – and calculates a diameter of 10.53 kilometers with an
absolute magnitude of 12.2.
Naming
This
minor planet was named in honor of American amateur astronomer and publisher Ken Graun (born 1955), author of two books on astronomy, owner of "Ken Press" and the website ''What's Out tonight?'', bringing astronomy to the broader public including children.
The official 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.
Function
...
on 9 March 2001 ().
References
External links
Asteroid Lightcurve Database (LCDB) query form
)
Dictionary of Minor Planet Names Google books
– Observatoire de Genève, Raoul Behrend
– Minor Planet Center
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009175
009175
Discoveries by Henry E. Holt
Named minor planets
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