A three-dimensional model of 158 Koronis based on its light curve.
|Discovery and designation|
|Discovered by||Viktor Knorre|
|Discovery date||January 4, 1876|
|Minor planet category||Main belt|
|Epoch August 27, 2011 (JD 2455800.5)|
|Aphelion||453.282 Gm (3.030 AU)|
|Perihelion||404.663 Gm (2.705 AU)|
|428.897 Gm (2.867 AU)|
|1775.077 d (4.86 a)|
Average orbital speed
Sidereal rotation period
|14.218 h (0.592 d)|
158 Koronis // is a main-belt asteroid that was discovered by Russian astronomer Viktor Knorre on January 4, 1876, from the Berlin observatory. It was the first of his four asteroid discoveries. The meaning of the asteroid name is uncertain, but it may come from Coronis the mother of Asclepius from Greek mythology. Alternatively, it may come from Coronis, a nymph of the Hyades sisterhood.
From its spectrum this is classified as an S-type asteroid, indicating a stony composition. Photometric observations show a synodic rotation period of 14.206 ± 0.002 hours with a brightness variation of 0.28–0.43 in magnitude. A subsequent study at the Altimira Observatory during 2010 was in agreement with this estimate, yielding a rotation period of 14.208 ± 0.040 hours. Based on a model constructed from the lightcurve, the shape of Koronis resembles that of Ida, although it is a bit larger. 
The asteroid itself may not be spectacular, but the Koronidian family of asteroids named after it is one of the most important. This cluster was created during a collision some 15 million years ago, with 158 Koronis retaining about 98% of the combined mass. One member of the family, 243 Ida, has been visited by spacecraft, and gives some idea of how the other asteroids in the family may look.
- Yeomans, Donald K., "158 Koronis", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30.
- DeMeo, Francesca E. et al. (July 2009), "An extension of the Bus asteroid taxonomy into the near-infrared", Icarus 202 (1): 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, retrieved 2013-04-08. See appendix A.
- "Numbered Minor Planets 1–5000", Discovery Circumstances (IAU Minor Planet center), retrieved 2013-04-07.
- Schmadel, Lutz D. (2012), Dictionary of Minor Planet Names (6th ed.), Springer, p. 27, ISBN 3642297188.
- Slivan, Stephen M. et al. (April 2003), "Spin vectors in the Koronis family: comprehensive results from two independent analyses of 213 rotation lightcurves", Icarus 162 (2): 285–307, Bibcode:2003Icar..162..285S, doi:10.1016/S0019-1035(03)00029-0.
- Buchheim, Robert K. (July 2011), "Phase Curves of 158 Koronis and 535 Montague", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers 38 (3): 128–130, Bibcode:2011MPBu...38..128B.
- Molnar, Lawrence A.; Haegert, M. J. (September 2009), "Details of Recent Collisions of Asteroids 832 Karin and 158 Koronis", American Astronomical Society, DPS meeting #41, #27.05, Bibcode:2009DPS....41.2705M.