| Discovery[1] | |
|---|---|
| Discovered by | K. W. Reinmuth |
| Discovery site | Heidelberg |
| Discovery date | 2 August 1949 |
| Designations | |
| (4979) Otawara | |
Named after | Akira Otawara[2] |
| 1949 PQ · 1977 DW10 · 1978 TY5 · 1978 SW4[1] | |
| main belt | |
| Orbital characteristics[3] | |
| Epoch 5 May 2025 (JD 2460800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 27736 days (75.94 yr) |
| Aphelion | 2.483AU |
| Perihelion | 1.852 AU |
| 2.167 AU | |
| Eccentricity | 0.1453 |
| 3.191yr (1166d) | |
| 298.626° | |
| 0° 18m 32.04s / day | |
| Inclination | 0.9092° |
| 69.799° | |
| 206.956° | |
| Earth MOID | 0.8363 AU |
| Jupiter MOID | 2.6125 AU |
| TJupiter | 3.677 |
| Physical characteristics | |
| Dimensions | ~3.204 km (JPL)[3] 2.6–4.0 km (Doressoundiram et al. 1999)[4]: 702 [a] |
Meandensity | ≥1.9 g/cm3[4]: 702 [b] |
| 2.707±0.005 h[5]: 662 | |
| 50±5° or230±5°[6] | |
| −30±16°[6] | |
| S-type[7]: 330 | |
| 14.43 (JPL)[3] | |
4979 Otawara (provisional designation:1949 PQ) is a small, rapidly rotatingasteroid orbiting in themain asteroid belt. Discovered in 1949, the asteroid was named after Japanese photo artist and writer Akira Otawara. It is stony in composition, consisting ofolivine andpyroxenes, and is estimated to be around 2–4 kilometres (1.2–2.5 mi) in size. The asteroid was one of three originally planned targets for theRosetta mission, but launch delays meant that it was abandoned.
Otawara was discovered on 2 August 1949 by German astronomerKarl Wilhelm Reinmuth, inHeidelberg. It was given theprovisional designation 1949 PQ,[1] and on 21 November 1991 it wasnumbered 4979 by theMinor Planet Center.[8] The asteroid was named after Akira Otawara, a photo artist and writer. Together with astronomerShuichi Nakano, he published two catalogs in 1983,Field Star Map 2000 andStar & Planet Catalogue 2000. Nakano proposed the nameOtawara for the object; the name was published in Minor Planet Circular 22505 on 1 September 1993.[2]
Otawara orbits with asemi-major axis of 2.17astronomical units (AU);[3] it is located in themain asteroid belt.[7]: 328 It has a moderateorbital eccentricity of 0.15. Along its 3.19 year (1166 day) orbit, its distance from theSun varies from 1.85 AU atperihelion to 2.48 AU ataphelion. Its orbit is closely aligned with the plane of the planets, with anorbital inclination of 0.91° with respect to theecliptic plane.[3]
Otawara is a small asteroid;[4]: 702 estimates of its size range around 2–4 kilometres (1.2–2.5 mi).[a] Otawara'slightcurve, or variations in its observed apparent brightness, suggests that it is elongated, with an a/b axis ratio of1.21±0.05.[6][7]: 330 Initial analysis of Otawara's spectrum in 1999, conducted by a team of astronomers led by Alain Doressoundiram, was ambiguous on whatasteroid taxonomic class it belonged to.[7]: 330 Its spectrum was consistent with either anS-type asteroid rich insilicate minerals, aV-type asteroid associated with4 Vesta, or an SV-type asteroid, with characteristics intermediate of the two.[4]: 702 However, later analysis by a team led by Sonia Fornasier ruled out a V-type classification, and concluded that Otawara is an S-class asteroid rich inolivine andpyroxenes. Under the Gaffey classification scheme, Otawara belongs to the S(IV) subclass. S(IV) asteroids are probable candidates for parent bodies ofordinary chondrite meteorites; Otawara's spectral similarity to thesemeteorites suggests it is notdifferentiated.[7]: 330–333 Otawara's density is constrained to be ≥1.9 g/cm3, although this is not valid if it is a solid object instead of arubble pile.[4]: 702
Analysis of Otawara's lightcurve suggests it rotates rapidly, with arotation period of2.707±0.005 hours, classifying it as a fast rotating asteroid.[7]: 329 [4]: 701 Its rotation appears to beretrograde—rotating clockwise—with its north pole pointed towards theecliptic south.[7]: 330 [6]
Otawara, along with140 Siwa, was planned as aflyby target for theEuropean Space Agency'sRosetta spacecraft mission on its way to comet46P/Wirtanen. Expected to encounter Otawara on 11 July 2006,Rosetta would have been able to image most of its surface due to its rotation.Rosetta would have been unable to measure Otawara's mass due to its small size and the spacecraft's flyby distance.[9][10]: 1122, 1127 Rosetta was originally set to launch in January 2003, but the failure of anAriane 5 rocket postponed the spacecraft's launch and forced the ESA to find new targets.[11][12]: ix Rosetta eventually launched successfully in 2004, visiting the main belt asteroids2867 Šteins and21 Lutetia before arriving at its newly selected primary target67P/Churyumov–Gerasimenko.[13][14]
Rosetta mission | ||
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| Equipment | ||
| Targets |
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