4674 Pauling, provisional designation , is a spheroidal binary Hungaria

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 innermost regions 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 4.5 kilometers in diameter. It was discovered by American astronomer

Eleanor Helin Eleanor Francis "Glo" Helin (née Francis, 19 November 1932 – 25 January 2009) was an American astronomer. She was principal investigator of the Near-Earth Asteroid Tracking (NEAT) program of NASA's Jet Propulsion Laboratory. (Some sources gi ...

at the U.S.

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 ...

, California, on 2 May 1989, and named after the American chemist and Nobel laureate

Linus Pauling Linus Carl Pauling ( ; February 28, 1901August 19, 1994) was an American chemist and peace activist. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. ''New Scientist'' called him one of the 20 gre ...

Orbit and classification

The bright E-type asteroid is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

. It orbits the Sun in the inner main-belt at a distance of 1.7–2.0 AU once every 2 years and 6 months (926 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 0.07 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 19 ° 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 ...

. The first precovery was taken at

in 1985, 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 4 years prior to its discovery.

Diameter and albedo

According to the surveys carried out by NASA's space-based Spitzer and WISE telescopes, the asteroid measures between 4.2 and 4.8 kilometers in diameter and has a surface

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 to 0.39.

Lightcurve

Several 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 for this asteroids were obtained from photometric observations between 2005 and 2015, most notably by Italian astronomer Silvano Casulli and American astronomer Brian Warner at the U.S. Palmer Divide Observatory, Colorado. The lightcurves 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 2.531–2.533 hours () with an exceptionally low brightness amplitude of less than 0.01 in

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 ...

, indicating that the body has a nearly spheroidal shape.

Moon

In 2004, a team of astronomers at

ESO The European Southern Observatory is an astronomical research organisation. ESO may also refer to: *Employee stock option (also: executive stock option) *'' Ether Saga Odyssey'', a fantasy massively multiplayer online role-playing game *''The Elde ...

Very Large Telescope The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with ...

, Chile, announced that Pauling is orbited by a small asteroid moon. The moon has received a provisional designation for natural satellites: S/2004 (4674) 1. It was believed to measure 2.5 kilometers in diameter (now rather 1.5 km, since the primary's size estimate has been reduced from 8 to 4.5 kilometers) and to orbit Pauling at a distance of 250 kilometers once every 1200 hours.

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 in honor of the American chemist, biochemist, peace activist, author, educator, and multiple Nobel laureate

(1901–1994). The naming took place on the occasion of his 90th birthday. Pauling had a renowned and several decade long career at Caltech, and was leading its Department of Chemistry and Chemical Engineering. In 1954 and 1962, he received the

Nobel Prize in Chemistry The Nobel Prize in Chemistry () is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outst ...

and the

Nobel Peace Prize The Nobel Peace Prize (Swedish language, Swedish and ) is one of the five Nobel Prizes established by the Will and testament, will of Sweden, Swedish industrialist, inventor, and armaments manufacturer Alfred Nobel, along with the prizes in Nobe ...

, respectively. Astronomer Eleanor Helin was one of his admirers. 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 30 March 1991 ().

Orbit and classification

Diameter and albedo

Lightcurve

Moon

Naming

Notes

References

External links