909 Ulla

909 Ulla
Orbital diagram of Ulla
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date7 February 1919
Designations
(909) Ulla
PronunciationGerman: [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 arc100.99 yr (36,886 d)
Aphelion3.8633 AU
Perihelion3.2217 AU
3.5425 AU
Eccentricity0.0906
6.67 yr (2,435 d)
180.34°
0° 8m 52.08s / day
Inclination18.797°
146.35°
232.64°
TJupiter3.0250
Physical characteristics
8.73 h[9]
  • 0.0343±0.001[8]
  • 0.037±0.001[7]
8.95[1][6][7][8]

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]

  1. ^ a b c Cite error: The named reference MPC-object was invoked but never defined (see the help page).
  2. ^ (German Names)
  3. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  4. ^ a b Cite error: The named reference springer was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference lcdb was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference jpldata was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference AKARI was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference SIMPS was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Lagerkvist-2001 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference De-Pra-2018 was invoked but never defined (see the help page).