5535 Annefrank (/ˌænˈfræŋk/), provisional designation 1942 EM, is a stony Florian asteroid and suspected contact binary from the inner asteroid belt, approximately 4.5 kilometers in diameter. It was used as a target to practice the flyby technique that the Stardust space probe would later use on the comet Wild 2.[8]
 Annefrank viewed by Stardust in 2002 | |
| Discovery [1] | |
|---|---|
| Discovered by | Karl Wilhelm Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 23 March 1942 |
| Designations | |
| (5535) Annefrank | |
Named after | Anne Frank (Holocaust victim)[2] |
| 1942 EM · 1978 EK6 1986 TV14 · 1991 BO2 | |
| main-belt · Flora [3] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 75.02 yr (27,400 days) |
| Aphelion | 2.3527 AU |
| Perihelion | 2.0721 AU |
| 2.2124 AU | |
| Eccentricity | 0.0634 |
| 3.29 yr (1,202 days) | |
| 23.021° | |
| 0° 17m 58.2s / day | |
| Inclination | 4.2473° |
| 120.64° | |
| 9.1351° | |
| Physical characteristics | |
| Dimensions | (6.6 x 5.0 x 3.4 km)[1] 4.34±0.23 km[4] 4.8 km[1] 4.94 km (calculated)[3] |
| 15.12 h[5] 15.156±0.0474 h[6] 21.33±0.990 h[7] | |
| 0.21±0.03[8] 0.24 (assumed)[3] 0.279±0.092[9] 0.311±0.056[4] | |
| S [3][8] | |
| 13.650±0.120 (R)[7] · 13.679±0.001 (R)[6] · 13.7[1][3][4] · 13.88±0.32[10] | |
Stardust · 81P/Wild · Earth · 5535 Annefrank · Tempel 1
The asteroid was discovered 23 March 1942, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany.[11] It was named after Anne Frank, a victim of the Holocaust.[2]
Orbit and classification edit
Annefrank is a member of the Flora family, one of the largest collisional populations of stony asteroids in the main-belt. It orbits the Sun in the inner main-belt at a distance of 2.1–2.4 AU once every 3 years and 3 months (1,202 days). Its orbit has an eccentricity of 0.06 and an inclination of 4° with respect to the ecliptic.[1]
The body's observation arc begins at Crimea–Nauchnij in 1978, with its identification as 1978 EK6, 36 years after its official discovery observation at Heidelberg.[11]
Physical characteristics edit
Annefrank has been characterized as a common S-type asteroid.[3][8]
Diameter, albedo and shape edit
On 2 November 2002, the Stardust space probe flew past Annefrank at a distance of 3079 km. Its images show the asteroid to be 6.6 × 5.0 × 3.4 km, twice as big as previously thought, and its main body shaped like a triangular prism with several visible impact craters.[8] From the photographs, the albedo of Annefrank was computed to be between 0.18 and 0.24.[8] Preliminary analysis of the Stardust imagery suggests that Annefrank may be a contact binary, although other possible explanations exist for its observed shape.[8]
Rotation and poles edit
In October 2006, ground-based photometric observations were used in an attempt to measure Annefrank's rotational period. Analysis of the ambiguous lightcurve gave a period of 15.12 hours and a brightness variation of 0.25 magnitude with two alternative period solutions of 12 and 22.8 hours, respectively (U=2).[3][5]
In January 2014, photometric observations at the Palomar Transient Factory gave a rotation period of 15.156 and 21.33 hours with an amplitude of 0.17 and 0.20 magnitude, respectively (U=2/2).[6][7]
The lightcurve data suggests that Annefrank is not Lambertian, meaning that surface features, such as shadows from boulders and craters, play a role in the object's perceived brightness and not just the asteroid's relative size when seen from that orientation.[5]
The body's shortest axis is approximately aligned perpendicular to its orbital plane.[8]
Naming edit
This minor planet was named after Anne Frank, the German-Dutch-Jewish diarist who died in a Nazi concentration camp during the Second World War.[2] The official naming citation was published by the Minor Planet Center on 14 May 1995 (M.P.C. 25230).[12]
References edit
External links edit
- A page with images from the Stardust flyby Archived 2011-09-27 at the Wayback Machine
- Ted Stryk's Stardust page, including enhanced images of 5535 Annefrank
- Asteroid Lightcurve Database (LCDB), query form (info Archived 2017-12-16 at the Wayback Machine)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
- 5535 Annefrank at the JPL Small-Body Database
