4432 McGraw-Hill
Main-belt asteroid
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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]
(at Kitt Peak, Arizona)
| Discovery[1] | |
|---|---|
| Discovered by | S. J. Bus |
| Discovery site | Siding Spring Obs. |
| Discovery date | 2 March 1981 |
| Designations | |
Named after | McGraw-Hill Telescope[1] (at Kitt Peak, Arizona) |
| 1981 ER22 · 1964 TV | |
| main-belt[1][2] · (inner)[3] background[4] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 53.54 yr (19,555 d) |
| Aphelion | 2.8975 AU |
| Perihelion | 1.8747 AU |
| 2.3861 AU | |
| Eccentricity | 0.2143 |
| 3.69 yr (1,346 d) | |
| 188.28° | |
| 0° 16m 2.64s / day | |
| Inclination | 0.4616° |
| 115.15° | |
| 246.30° | |
| Physical characteristics | |
| 3.042±0.643 km[5][6] 3.43 km (derived)[3] | |
| inconclusive[3][7] | |
| 0.20 (assumed)[3] 0.254±0.224[5][6] | |
| S (assumed)[3] | |
| 14.5[1][2] 14.69[3][6][7] | |
Orbit and classification
McGraw-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 characteristics
McGraw-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 period
During 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 albedo
According 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]
Naming
This 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]
