909 Ulla
Outer main-belt asteroid / From Wikipedia, the free encyclopedia
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909 Ulla is a large and dark asteroid from the outermost regions of the asteroid belt, that measures approximately 116 kilometers (72 miles) in diameter. It is the parent body and namesake of the Ulla family, which belongs to the larger group of Cybele asteroids. It was discovered on 7 February 1919, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany.[1] The X-type asteroid has a rotation period of 8.7 hours and a notably low value for its Jupiter Tisserand's parameter. It was named after Ulla Ahrens, daughter of a friend of the discoverer.[4]
Quick Facts Discovery, Discovered by ...
![]() Orbital diagram of Ulla | |
Discovery [1] | |
---|---|
Discovered by | K. Reinmuth |
Discovery site | Heidelberg Obs. |
Discovery date | 7 February 1919 |
Designations | |
(909) Ulla | |
Pronunciation | German: [ˈʊlaː][2] Classically: /ˈʌlə/[3] |
Named after | Ulla Ahrens [4] (observatory donor) |
1919 FA · 1936 SJ 1949 OF1 · 1949 PW 1966 BU · 1966 DM A912 CA · A919 CA | |
main-belt · (outer) [5] Ulla · Cybele | |
Orbital characteristics [6] | |
Epoch 31 May 2020 (JD 2459000.5) | |
Uncertainty parameter 0 | |
Observation arc | 100.99 yr (36,886 d) |
Aphelion | 3.8633 AU |
Perihelion | 3.2217 AU |
3.5425 AU | |
Eccentricity | 0.0906 |
6.67 yr (2,435 d) | |
180.34° | |
0° 8m 52.08s / day | |
Inclination | 18.797° |
146.35° | |
232.64° | |
TJupiter | 3.0250 |
Physical characteristics | |
8.73 h[9] | |
8.95[1][6][7][8] | |
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