4432 McGraw-Hill
4432 McGraw-Hill, provisional designation 1981 ER22, is a background asteroid from the inner regions of the asteroid belt, approximately 3 kilometers (2 miles) in diameter. It was discovered on 2 March 1981, by American astronomer Schelte Bus at the Siding Spring Observatory in Australia. The likely S-type asteroid was named for the McGraw-Hill Telescope located at Kitt Peak, Arizona.[1] Orbit and classificationMcGraw-Hill is a non-family asteroid from the main belt's background population.[4] It orbits the Sun in the inner asteroid belt at a distance of 1.9–2.9 AU once every 3 years and 8 months (1,346 days; semi-major axis of 2.39 AU). Its orbit has an eccentricity of 0.21 and an inclination of 0° with respect to the ecliptic.[2] The asteroid was first observed as 1964 TV at Purple Mountain Observatory in October 1964. The body's observation arc begins with a precovery taken at Palomar Observatory in February 1977, or four years prior to its official discovery observation at Siding Spring.[1] Physical characteristicsMcGraw-Hill is an assumed, stony S-type asteroid,[3] in agreement with the albedo (see below) obtained by the Wide-field Infrared Survey Explorer (WISE). Rotation periodDuring the Small Main-Belt Asteroid Lightcurve Survey, McGraw-Hill has been observed photometrically. The observations gave a small brightness variation of 0.06 magnitude but resulted in no useful rotational lightcurve (U=n.a.).[7] As of 2018, the body's rotation period, pole and shape remain unknown.[2] Diameter and albedoAccording to the survey carried out by the NEOWISE mission of NASA's WISE telescope, McGraw-Hill measures 3.042 kilometers in diameter and its surface has an albedo of 0.254,[5][6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20 and derives a diameter of 3.43 kilometers based on an absolute magnitude of 14.69.[3] NamingThis minor planet was named after the 1.3-meter McGraw-Hill Telescope located at the MDM Observatory at the Kitt Peak National Observatory site in Arizona, United States.[1] The official naming citation was published by the Minor Planet Center on 18 February 1992 (M.P.C. 19697).[8] References
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