1999 Hirayama
| Discovery [1] | |
|---|---|
| Discovered by | L. Kohoutek |
| Discovery site | Bergedorf Obs. |
| Discovery date | 27 February 1973 |
| Designations | |
| MPC designation | 1999 Hirayama |
|
Named after
|
Kiyotsugu Hirayama (astronomer)[2] |
| 1973 DR · 1935 GF 1940 EH · 1951 EY1 1951 FA · 1965 UF 1969 NB · 1975 NE |
|
| main-belt · (outer) [3] | |
| Orbital characteristics [1] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 75.96 yr (27745 days) |
| Aphelion | 3.4706 AU (519.19 Gm) |
| Perihelion | 2.7579 AU (412.58 Gm) |
| 3.1143 AU (465.89 Gm) | |
| Eccentricity | 0.11442 |
| 5.50 yr (2007.4 d) | |
| 291.94° | |
| Inclination | 12.534° |
| 148.05° | |
| 356.88° | |
| Earth MOID | 1.7702 AU (264.82 Gm) |
| Jupiter MOID | 1.54473 AU (231.088 Gm) |
| Physical characteristics | |
| Dimensions | 33.95 km[4] 35.68±0.55 km[5] 38.28±0.40 km[6] 33.81 km (derived)[3] |
|
Mean radius
|
16.975 ± 1.05 km |
| Mass | 4.1×1016 kg[citation needed] |
| 15.63 h (0.651 d)[1][7] 22.37±0.03 h[8] 13.5921±0.0003 h[lower-alpha 1] |
|
| 0.0882 ± 0.012[1][4] 0.082±0.003[5] 0.053±0.005[6] 0.0675 (derived)[3] |
|
| C [3] | |
| 11.0[1] 10.6[7] |
|
1999 Hirayama, provisional designation 1973 DR, is a carbonaceous asteroid from the outer region of the asteroid belt, about 34 kilometers in diameter. It was discovered by Czech astronomer Luboš Kohoutek at the Hamburger Bergedorf Observatory, Germany, on 27 February 1973.[9]
The C-type asteroid orbits the Sun at a distance of 2.8–3.5 AU once every five and a half years (2,008 days). Its orbit shows an eccentricity of 0.11 and is tilted by 13 degrees to the plane of the ecliptic. According to the surveys carried out by the space-based IRAS, Akari and WISE satellites and the subsequent NEOWISE mission, the body's surface has an albedo in the range of 0.05–0.09.[4][5][6]
The light curve analysis showed a periodicity of 15.63±0.01 hours, during which time the brightness of the object varies by 0.45±0.04 in magnitude.[7] The spectrum of this object matches a C-type Tholen classification, but with a "broad absorption band that can be associated to a process of aqueous alteration".[10] That is, the surface appears to show some form of water modification. A more recent observations rendered a somewhat shorter period of 13.6 hours.[lower-alpha 1]
The minor planet is named in honour of Japanese astronomer Kiyotsugu Hirayama (1874–1943), best known for his discovery that many asteroid orbits were more similar to one another than chance would allow, leading to the concept of asteroid families, now called Hirayama families. The lunar carter Hirayama is also named in his honour.[2]
References
- ↑ 1.0 1.1 Hamanowa (2011) web: rotation period 13.5921±0.0003 hours with a brightness amplitude of 0.57 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1999) Hirayama
- ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 3.2 3.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.0 4.1 4.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 5.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 6.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 7.0 7.1 7.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
External links
- Asteroid Lightcurve Database (LCDB), query form (info)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- 1999 Hirayama at the JPL Small-Body Database
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