817 Annika
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| Discovery[1] | |
|---|---|
| Discovered by | M. F. Wolf |
| Discovery site | Heidelberg Obs. |
| Discovery date | 6 February 1916 |
| Designations | |
| (817) Annika | |
| Pronunciation | /ˈænɪkə/ German: [ˈanikaː][2] |
Named after | a girl named "Anika"[3] |
| A916 · CD 1916 YW | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 103.99 yr (37,982 d) |
| Aphelion | 3.0570 AU |
| Perihelion | 2.1231 AU |
| 2.5900 AU | |
| Eccentricity | 0.1803 |
| 4.17 yr (1,523 d) | |
| 61.065° | |
| 0° 14m 11.4s / day | |
| Inclination | 11.336° |
| 125.47° | |
| 285.18° | |
| Physical characteristics | |
| Dimensions | 22.0 km × 22.0 km |
Mean density | ~2.7 g/cm3 (estimate)[13] |
817 Annika (prov. designation: A916 CD or 1916 YW) is a background asteroid in the region of the Eunomia family, located in the central portion of the asteroid belt. It was discovered on 6 February 1916, by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southwest Germany.[1] The stony S-type asteroid (Sl) has a rotation period of 10.56 hours and measures approximately 23 kilometers (14 miles) in diameter .[3]
Annika is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method (HCM) to its proper orbital elements by Nesvorný as well as by Milani and Knežević (AstDyS).[5][6] In the 1995 HCM-analysis by Zappalà,[8] however, Annika is a member of the Eunomia family (502), a prominent family of stony asteroids and the largest one in the intermediate main belt with more than 5,000 members.[7] It orbits the Sun in the central main-belt at a distance of 2.1–3.1 AU once every 4 years and 2 months (1,523 days; semi-major axis of 2.59 AU). Its orbit has an eccentricity of 0.18 and an inclination of 11° with respect to the ecliptic.[4] The body's observation arc begins with its official discovery observation at Heidelberg Observatory on 6 February 1916.[1]
Naming
"Annika" is a common German feminine given name. Any reference to a person or occurrence for the naming of this minor planet is unknown.[3]
Unknown meaning
Among the many thousands of named minor planets, Annika is one of 120 asteroids for which no official naming citation has been published. All of these asteroids have low numbers, the first being 164 Eva. The last asteroid with a name of unknown meaning is 1514 Ricouxa. They were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth.[17]
