258 Tyche

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258 Tyche
258Tyche (Lightcurve Inversion).png
Light curve-based 3D-model of 258 Tyche
Discovery [1]
Discovered by R. Luther
Discovery site Düsseldorf-Bilk Obs.
Discovery date 4 May 1886
Designations
MPC designation 258 Tyche
Named after
Tyche[2]
Eunomia · main-belt
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 129.95 yr (47465 d)
Aphelion 3.1512 AU (471.41 Gm)
Perihelion 2.0838 AU (311.73 Gm)
2.6175 AU (391.57 Gm)
Eccentricity 0.20390
4.23 yr (1546.8 d)
18.42 km/s[citation needed]
157.95°
0° 13m 57.864s / day
Inclination 14.305°
207.59°
155.01°
Earth MOID 1.09016 AU (163.086 Gm)
Jupiter MOID 2.34517 AU (350.832 Gm)
Jupiter Tisserand parameter 3.334
Physical characteristics
Dimensions 64.78±1.2 km[1]
65 km [3]
Mass ~ 4×1017 (estimate)
Mean density
~ 2.7 g/cm³[4]
10.041 h (0.4184 d) [1][5]
0.1676±0.006[1]
0.168 [3]
Temperature ~ 169 K
max: 268 K[citation needed]
B–V = 0.876
U–B = 0.459
S (Tholen), S (SMASS)
8.50

258 Tyche is a relatively large main belt asteroid discovered by Robert Luther at Düsseldorf-Bilk Observatory on 4 May 1886.[1] The stony S-type asteroid measures about 65 kilometers in diameter and has a perihelion of 2.1 AU.[1]

Tyche orbits very close to the Eunomia family of asteroids, and could be a member based on composition. However, it is larger than all family members apart from 15 Eunomia while lying at the very edge of the family group. Hence, there is a good chance that it is an unrelated interloper.

There is some uncertainty regarding Tyche's rotation period. Various authors give values from 9.983 to 10.041 hours.[6]

It was named after Greek goddess of fortune, Tyche, which is also the name of one of the Oceanids. Tyche's Roman equivalent is Fortuna, after which the asteroid 19 Fortuna is named.[2]

References[edit]

  1. ^ a b c d e f g "JPL Small-Body Database Browser: 258 Tyche" (2015-09-21 last obs.). Jet Propulsion Laboratory. Retrieved 11 May 2016. 
  2. ^ a b Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (258) Tyche. Springer Berlin Heidelberg. p. 38. ISBN 978-3-540-29925-7. Retrieved October 2015. 
  3. ^ a b Supplemental IRAS Minor Planet Survey
  4. ^ G. A. Krasinsky et al. Hidden Mass in the Asteroid Belt, Icarus, Vol. 158, p. 98 (2002).
  5. ^ PDS lightcurve data
  6. ^ D. Riccioli, C. Blanco, & M. Cigna Rotational periods of asteroids II, Planetary and Space Science, Vol. 49,, p. 657 (2001).

External links[edit]