C/2013 A1 (Siding Spring)

For other uses, see Siding Spring.

C/2013 A1 (Siding Spring)
Comet Siding Spring as seen by Hubble on 11 March 2014
Discovery
Discovered bySiding Spring Observatory
0.5-m Schmidt (E12)[1]
Discovery date3 January 2013[1]
Orbital characteristics
Epoch2014-Oct-30
(JD 2456960.5)[2]
Observation arc3.53 years
Number of
observations		449
Orbit typeOort cloud
Aphelion52000 AU (inbound)
13000 AU (outbound)[3]
Perihelion1.39875 AU (q)
Eccentricity1.00043
Orbital periodseveral million years inbound (Barycentric solution for epoch 1950)[3]
~500000 years outbound
(Barycentric solution for epoch 2050)[3]
Inclination129.0°
Last perihelion25 October 2014
Jupiter MOID3.67 AU
Physical characteristics
Dimensions~400–700 meters (0.2–0.4 mi)[4][5]

C/2013 A1 (Siding Spring) is an Oort cloud comet discovered on 3 January 2013 by Robert H. McNaught at Siding Spring Observatory using the 0.5-meter (20 in) Uppsala Southern Schmidt Telescope.[1][6]

At the time of discovery it was 7.2 AU from the Sun and located in the constellation Lepus. Comet C/2013 A1 probably took millions of years to come from the Oort cloud. After leaving the planetary region of the Solar System, the post-perihelion orbital period (epoch 2050) is estimated to be roughly 1 million years.[3]

C/2013 A1 passed the planet Mars very closely on 19 October 2014, at a distance of 140,496.6 ± 4.0 km (87,300.5 ± 2.5 mi; 0.000939162 ± 2.7×10−8 au).[7] After its discovery, there was thought to be a chance of a collision with Mars, but this possibility was excluded when its orbit was determined with about a 200-day observation arc.[8]

All NASA Mars orbiters—including 2001 Mars Odyssey,[9] Mars Reconnaissance Orbiter[10] and MAVEN[11]—as well as ESA's orbiter, Mars Express,[12] and ISRO's orbiter, the Mars Orbiter Mission,[13] reported a healthy status after the comet flyby on 19 October 2014.[14][15] During the flyby, orbiters around Mars detected thousands of kilograms per hour of comet dust composed of magnesium, iron, sodium, potassium, manganese, nickel, chromium and zinc.[16] In addition, the comet nucleus was determined to be between 400 and 700 meters (0.2 and 0.4 mi),[4][5][16] much smaller than originally assumed. The nucleus rotates once every eight hours.[17]

  1. ^ a b c Cite error: The named reference MPEC2013-A14 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference MPEC2014-L52 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference barycenter was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference HiRISE141021 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Swift was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference NYT-20140804 was invoked but never defined (see the help page).
  7. ^ Farnocchia, D.; Chesley, S.R.; Micheli, M.; Delamere, W.A.; Heyd, R.S.; Tholen, D.J.; Giorgini, J.D.; Owen, W.M.; Tamppari, L.K. (2016). "High precision comet trajectory estimates: The Mars flyby of C/2013 A1 (Siding Spring)". Icarus. 266: 279–287. arXiv:1507.01980. Bibcode:2016Icar..266..279F. doi:10.1016/j.icarus.2015.10.035. ISSN 0019-1035. S2CID 118874989.
  8. ^ Cite error: The named reference esa was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference NASA-20141019-ODY was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference NASA-20141019-MRO was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference NASA-20141019-MAV was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference ESA-20141020 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference ISRO MOM safe after Mars comet flyby was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference NASA-20141019 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference NYT-20141019 was invoked but never defined (see the help page).
  16. ^ a b Cite error: The named reference NYT-20141107-KC was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference JPL141107 was invoked but never defined (see the help page).