5641 McCleese, provisional designation , is a rare-type Hungaria asteroid and slow rotator, classified as

Mars-crosser A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for in ...

from the innermost 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, c ...

, approximately 4 kilometers in diameter. It was discovered on 27 February 1990, 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 Palomar Observatory in California, and later named for JPL-scientist Daniel McCleese.

Classification and orbit

''McCleese'' is classified as a bright and rare

A-type asteroid A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 μm olivine feature and a very reddish spectrum shortwards of 0.7 μm. They are thought to come from the completely differentiated mantle of an asteroi ...

in the SMASS taxonomy. It is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. With a

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elli ...

of 1.589 AU, ''McCleese'' also crosses the orbit of Mars. The asteroid orbits the Sun in the innermost main-belt at a distance of 1.6–2.0 AU once every 2 years and 5 months (896 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 0.13 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 22 ° 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 agains ...

. In 1973, it was first identified as at Lick Observatory, extending 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 ...

by 17 years prior to its official discovery observation at Palomar.

Lightcurve

Photometric observations of ''McCleese'' by Brian Warner and René Roy in 2005 and 2007, gave three 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 freq ...

s that had a rotation period between 7.2 and 28.8 hours with a brightness variation of 0.06 to 0.50

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 ...

(). In June 2010, ''McCleese'' was again observed by Brian Warner at his Palmer Divide Observatory in Colorado, United States. By combining his data points with the previously obtained photometric data, he was able to derive a period of hours with an amplitude of 1.30 magnitude (). With a period of 418 hours, the body is one of the Top 100 slow rotators known to exist.

Diameter estimates

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 201 ...

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 201 ...

mission, ''McCleese'' measures 5.68 and 4.00 kilometers in diameter, and its surface has an

albedo Albedo (; ) is the measure of the diffuse reflection of 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 that refl ...

of 0.455 and 0.34, respectively. In agreement with WISE, the ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.3 and derives a diameter of 3.67 kilometers using an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it ...

of 14.1.

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 ''mino ...

is named after American JPL scientist Daniel J. McCleese, who is a physicist and manager at JPL's Science Division. He also played an important role for the

Near-Earth Asteroid Tracking Near-Earth Asteroid Tracking (NEAT) was a program run by NASA and the Jet Propulsion Laboratory, surveying the sky for near-Earth objects. NEAT was conducted from December 1995 until April 2007, at GEODSS on Hawaii (Haleakala-NEAT; 566), as we ...

program (NEAT). The approved naming citation was published by the Minor Planet Center on 4 April 1996 ().

References

External links

Lightcurve plot of 5641 McCleese
Palmer Divide Observatory, B. D. Warner (2010)
Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:005641 Mars-crossing asteroids Hungaria asteroids McCleese McCleese Slow rotating minor planets A-type asteroids (SMASS) 19900227