| Discovery[1] | |
|---|---|
| Discovered by | J. Gibson C. U. Cesco |
| Discovery site | El Leoncito |
| Discovery date | 16 September 1971 |
| Designations | |
| (1919) Clemence | |
Named after | Gerald Clemence (astronomer)[2] |
| 1971 SA · 1970 EA1 1971 QZ | |
| main-belt · (inner)[1] Hungaria[3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 46.23 yr (16,884 days) |
| Aphelion | 2.1200AU |
| Perihelion | 1.7522 AU |
| 1.9361 AU | |
| Eccentricity | 0.0950 |
| 2.69yr (984 days) | |
| 286.44° | |
| 0° 21m 57.24s / day | |
| Inclination | 19.337° |
| 357.00° | |
| 99.880° | |
| Physical characteristics | |
| Dimensions | 3.238±0.015 km[5] 3.276±0.010[6] 4.95 km(calculated)[4] |
| 67.4±0.1h(revised)[7] 68.5±0.1 h(original)[8] | |
| 0.3(assumed)[4] 0.686±0.108[6] 0.7103±0.0672[5] | |
| Tholen =X[1] X[4] · E[5] B–V = 0.750[1] U–B = 0.254[1] | |
| 13.45[1][4][5] | |
1919 Clemence, provisional designation1971 SA, is a bright Hungariaasteroid and suspected tumbler from the inner regions of theasteroid belt, approximately 4 kilometers in diameter. It was discovered on 16 September 1971, by American astronomer James Gibson together with Argentine astronomerCarlos Cesco at the Yale-Columbia Southern Station atLeoncito Astronomical Complex in Argentina.[3] It is named after astronomerGerald Clemence.[2]
Clemence is a member of theHungaria family, which form theinnermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.8–2.1 AU once every 2 years and 8 months (984 days). Its orbit has aneccentricity of 0.10 and aninclination of 19° with respect to theecliptic.[1]
In theTholen taxonomic scheme,Clemence is classified as anX-type asteroid.[1] It has also been characterized as anE-type asteroid by theNEOWISE mission.[5]
In March 2005, a rotationallightcurve was obtained by American astronomerBrian Warner at his Palmer Divide Observatory (716) in Colorado. Lightcurve analysis gave arotation period of67.4±0.1 hours and a brightness variation of0.15magnitude (U=2, revised analysis).[7] While not being aslow rotator,Clemence has a significantly longer period than most other asteroids, which typically have a spin rate between 2 and 20 hours.
Czech astronomerPetr Pravec from theOndřejov Observatory believes this may be a tumbling asteroid, yet observations are not sufficient to determine a non-principal axis rotation.[8][9]
According to the surveys carried out by the NEOWISE mission of NASA'sWide-field Infrared Survey Explorer, the asteroid measures 3.2 kilometers in diameter and its surface has an outstandingly highalbedo of 0.71,[5] while theCollaborative Asteroid Lightcurve Link assumes an albedo of 0.30 and calculates a somewhat larger diameter of 4.95 kilometers with anabsolute magnitude of 13.45.[4]
Thisminor planet was named after American astronomerGerald Maurice Clemence (1908–1974), first scientific director of theUnited States Naval Observatory and professor of astronomy at theYale Observatory, known for his work on the theory of the motion of Mars and Mercury, on the system of astronomical constants, and other research incelestial mechanics. He served as president of theAmerican Astronomical Society and ofIAU.[2] The officialnaming citation was published by theMinor Planet Center on 20 February 1976 (M.P.C. 3937).[10]
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