Comet ISON

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C/2012 S1 (ISON)
File:Cometa-ISON.jpg
Comet ISON as seen on 22 September with a 0.25-metre (9.8 in) reflector[1]
Discovery
Discovered byVitaly Nevsky,
Artyom Novichonok
ISON-Kislovodsk
0.4-m reflector (D00)[1]
Discovery date21 September 2012
Orbital characteristics
Epoch14 Dec 2013
(JD 2456640.5)[2]
Perihelion0.0124 AU (q)[2]
Eccentricity1.00[2]
Orbital period900,000 years (epoch 2050)[3]
Inclination62.4°[2]
Next perihelion28 November 2013[2]

C/2012 S1 (ISON) is a sungrazing comet discovered on 21 September 2012 by Vitali Nevski (Виталий Невский, Vitebsk, Belarus) and Artyom Novichonok (Артём Новичонок, Kondopoga, Russia). The discovery was made using the 0.4-metre (16 in) reflector of the International Scientific Optical Network near Kislovodsk, Russia.[1] Precovery images by the Mount Lemmon Survey from 28 December 2011 and by Pan-STARRS from 28 January 2012 were quickly located.[4] Follow-up observations were made on 22 September by a team from Remanzacco Observatory in Italy using the iTelescope network.[1][5] The discovery was announced by the Minor Planet Center on 24 September, three days after the discovery.[4]

Orbit

Orbital position of Comet ISON on 11 December 2013 after perihelion.

The preliminary orbit shows the comet will come to perihelion (closest approach to the Sun) on 28 November 2013 at a distance of 0.012 AU (1,800,000 km; 1,100,000 mi) from the center point of the Sun.[2] Accounting for the solar radius of 6.955×105 km, the comet will pass approximately 1,100,000 kilometres (680,000 mi) above the Sun's surface. Its orbit is nearly parabolic, which suggests that it may be a new comet coming fresh from the Oort cloud.[6][7] Preliminary calculations show that, on closest approach, the comet will pass about 0.07 AU (10,000,000 km; 6,500,000 mi) from Mars on 1 October 2013, and it will pass about 0.4 AU (60,000,000 km; 37,000,000 mi) from Earth on 26 December 2013.[8] Some of the orbital elements of comet ISON are similar to that of the Great Comet of 1680 and the two comets may have fragmented from the same parent body.[9]

Brightness

At the time of its discovery, the comet's apparent magnitude was about 18.8, far too dim to be seen with the naked eye but bright enough to be imaged by amateurs with large telescopes.[10][11] It will gradually increase in brightness as it approaches. Around August 2013 it should be visible through small telescopes or binoculars, becoming visible to the naked eye by late October or early November and remaining so until mid-January 2014.[11][6] When the comet reaches its perihelion on 28 November it may be less than 1° from the Sun, making it difficult to see against the glare of the Sun.[12] The comet may become extremely bright if it remains intact, probably reaching a negative magnitude.[5] According to Astronomy Now, it may briefly become brighter than the full Moon.[7][6] But predicting the brightness of a comet is difficult, especially one that will pass so close to the Sun and be affected by the forward scattering of light. Comet Kohoutek and C/1999 S4 did not meet expectations, but if ISON survives it could look similar to the Great Comet of 1680, the Great Comet of 2007 or C/2011 W3 (Lovejoy).[5][13] The brightest comet since 1935 was Comet Ikeya–Seki in 1965 at magnitude -10.[14] Comet ISON will be well placed for northern hemisphere observers in mid to late December 2013.[15]

See also

  • C/2011 L4 — may also be visible to the naked eye when it is near perihelion in March 2013.

References

  1. ^ a b c d Giovanni Sostero, Nick Howes, and Ernesto Guido (24 September 2012). "New Comet: C/2012 S1 (ISON)". Team of observers of Remanzacco Observatory in Italy. Retrieved 24 September 2012.{{cite web}}: CS1 maint: multiple names: authors list (link)
  2. ^ a b c d e f "MPEC 2012-T08 : OBSERVATIONS AND ORBITS OF COMETS". IAU Minor Planet Center. 3 October 2012. Retrieved 4 October 2012.
  3. ^ Horizons output. "Barycentric Osculating Orbital Elements for Comet C/2012 S1 (ISON)". Retrieved 28 September 2012. (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)
  4. ^ a b "MPEC 2012-S63 : COMET C/2012 S1 (ISON)". IAU Minor Planet Center. 24 September 2012. Retrieved 24 September 2012. (CK12S010)
  5. ^ a b c Atkinson, Nancy. "New 'Sun-Skirting' Comet Could Provide Dazzling Display in 2013". Universetoday.com. Retrieved 28 September 2012.
  6. ^ a b c Grego, Peter. "New comet might blaze brighter than the full Moon". Astronomy Now. Retrieved 28 September 2012.
  7. ^ a b Hecht, Jeff. "Newly spotted comet may outshine the full moon". New Scientist. Retrieved 28 September 2012.
  8. ^ "JPL Close-Approach Data: C/2012 S1 (ISON)". 2012-10-02 last obs (arc=279 days). Retrieved 2012-10-04. {{cite web}}: Check date values in: |date= (help)
  9. ^ J. Bortle (24 September 2012). "the orbital elements' distinct and surprising similarity to those of the Great Comet of 1680". comets-ml · Comets Mailing List. Retrieved 5 October 2012.
  10. ^ Rao, Joe. "Newfound Comet C/2012 S1 May Dazzle in 2013". Space.com. Retrieved 28 September 2012.
  11. ^ a b Bakich, Michael E. "New comet will light up the sky". Astronomy. Retrieved 28 September 2012.
  12. ^ Kelly Beatty (27 September 2012). "A "Dream Comet" Heading Our Way?". Sky & Telescope. Retrieved 28 September 2012.
  13. ^ Alan Boyle. "Super-comet or super-dud? We'll see". Cosmic Log. Retrieved 27 September 2012.
  14. ^ "Brightest comets seen since 1935". International Comet Quarterly. Retrieved 28 September 2012.
  15. ^ David Dickinson (25 September 2012). "Will we have a Christmas comet in 2013?". Retrieved 30 September 2012.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Comet_ISON&oldid=516280864"