52246 Donaldjohanson
| Discovery [1] | |
|---|---|
| Discovered by | S. J. Bus |
| Discovery site | Siding Spring Obs. |
| Discovery date | 2 March 1981 |
| Designations | |
| (52246) Donaldjohanson | |
Named after | Donald Johanson (paleoanthropologist)[2] |
| 1981 EQ5 · 1998 YF26 | |
| main-belt · (inner) Erigone [3] | |
| Orbital characteristics [1] | |
| Epoch 16 February 2017 (JD 2457800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 35.96 yr (13,133 days) |
| Aphelion | 2.8269 AU |
| Perihelion | 1.9413 AU |
| 2.3841 AU | |
| Eccentricity | 0.1857 |
| 3.68 yr (1,345 days) | |
| 317.07° | |
| 0° 16m 3.72s / day | |
| Inclination | 4.4192° |
| 262.85° | |
| 213.00° | |
| Physical characteristics | |
| Dimensions | 3.895±0.013 km[4] |
| 0.103±0.019[4] | |
| C [3] | |
| 15.5[1] | |
52246 Donaldjohanson, provisional designation 1981 EQ5, is a carbonaceous Erigonian asteroid from the inner regions of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 2 March 1981, by American astronomer Schelte Bus at the Siding Spring Observatory in Australia. The asteroid is a target of the Lucy mission and was aptly named after American paleoanthropologist Donald Johanson.[2]
Orbit and classification
Donaldjohanson is a carbonaceous C-type asteroid and member of the small Erigone family, which is named after its namesake 163 Erigone.[3] It orbits the Sun in the inner main-belt at a distance of 1.9–2.8 AU once every 3 years and 8 months (1,345 days). Its orbit has an eccentricity of 0.19 and an inclination of 4° with respect to the ecliptic.[1] A first precovery was taken at the discovering observatory in February 1981, extending the body's observation arc by 2 weeks prior to its official discovery observation.[2]
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Donaldjohanson measures 3.895 kilometers in diameter and its surface has an albedo of 0.103.[4] It has an absolute magnitude of 15.5.[1] As of 2017, Donaldjohanson's rotation period and shape remain unknown, as no rotational lightcurve has been obtained.[5]
Naming
This minor planet is planned to be visited by the Lucy spacecraft, which would observe it en route to its main target of several Jupiter trojans.[6] The Lucy probe is named after the "Lucy" hominid fossil, while Donaldjohanson is named for that fossil's co-discoverer, the American paleoanthropologist Donald Johanson (born 1943). Naming citation was published on 25 December 2015 (M.P.C. 97569).[2][7]
Lucy mission target
Donaldjohanson is planned to be visited by the Lucy spacecraft. The fly by is scheduled for 20 April 2025, and will approach the asteroid to a distance of 922 kilometers at a velocity of 13.4 kilometers per hour.[3] The mission's targets with their flyby dates are:[3][6]
- 52246 Donaldjohanson — April 2025: 4 km diameter C-type asteroid in the inner main-belt, member of ~130Myr old Erigone family
- 3548 Eurybates — August 2027: 64 km diameter C-type Jupiter Trojan in the Greek camp at L4, largest member of the only confirmed disruptive collisional family in the Trojans
- 15094 Polymele — September 2027: 21 km diameter P-type Trojan at L4, likely collisional fragment
- 11351 Leucus — April 2028: 34 km diameter D-type slow rotator Trojan at L4
- 21900 Orus — October 2028: 51 km diameter D-type Trojan at L4
- 617 Patroclus — March 2033: P-type binary Trojan. The primary, Patroclus, has a mean diameter of 113 km and its companion, Menoetius, has a diameter of 104 km. The pair orbit at a separation of 680 km. The binary resides in the Trojan camp at L5
See also
References
- ^ a b c d e "JPL Small-Body Database Browser: 52246 Donaldjohanson (1981 EQ5)" (2017-01-29 last obs.). Jet Propulsion Laboratory. Retrieved 12 April 2017.
- ^ a b c d "52246 Donaldjohanson (1981 EQ5)". Minor Planet Center. Retrieved 12 April 2017.
- ^ a b c d e Levison, H. F.; Olkin, C.; Noll, K. S.; Marchi, S.; Lucy Team (March 2017). "Lucy: Surveying the Diversity of the Trojan Asteroids: The Fossils of Planet Formation" (PDF). 48th Lunar and Planetary Science Conference. Bibcode:2017LPI....48.2025L. Retrieved 13 April 2017.
- ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 12 April 2017.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ "LCDB Data for (52246) Donaldjohanson". Asteroid Lightcurve Database (LCDB). Retrieved 12 April 2017.
- ^ a b Casey Dreier; Emily Lakdawalla (30 September 2015). "NASA announces five Discovery proposals selected for further study". The Planetary Society. Retrieved 12 April 2017.
- ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 12 April 2017.
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 (50001)-(55000) – Minor Planet Center
- 52246 Donaldjohanson at the JPL Small-Body Database
