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'''C/2012 S1''', also known as '''Comet ISON''' or '''Comet Nevski–Novichonok''', is a [[sungrazing comet]] discovered on 21 September 2012 by Vitali Nevski (Виталий Невский, [[Vitebsk]], [[Belarus]]) and Artyom Novichonok ([[:ru:Новичонок, Артём Олегович|Артём Новичонок]], [[Kondopoga]], [[Russia]]).<ref name="Trigo-Rodriguez2013"/> The discovery was made using the {{convert|0.4|m|in|adj=on|sp=us}} [[reflecting telescope|reflector]] of the [[International Scientific Optical Network]] near [[Kislovodsk]], Russia and the automated asteroid-discovery program CoLiTec.<ref name="Remanzacco"/><ref name="NAS20121012"/> [[Precovery]] images by the [[Mount Lemmon Survey]] from 28 December 2011 and by [[Pan-STARRS]] from 28 January 2012 were quickly located.<ref name="MPEC2012-S63"/> Follow-up observations were made on 22 September by a team from Remanzacco Observatory in Italy using the [[iTelescope]] network.<ref name="Remanzacco"/><ref name="universetoday1"/> The discovery was announced by the [[Minor Planet Center]] on 24 September.<ref name="MPEC2012-S63"/> Observations by [[Swift Gamma-Ray Burst Mission|SWIFT]] suggest that C/2012 S1's [[comet nucleus|nucleus]] is around {{convert|5|km|sp=us}} in diameter.<ref name="Swift"/>
'''C/2012 S1''', also known as '''Comet ISON''' or '''Comet Nevski–Novichonok''', is a [[sungrazing comet]] discovered on 21 September 2012 by Vitali Nevski (Виталий Невский, [[Vitebsk]], [[Belarus]]) and Artyom Novichonok ([[:ru:Новичонок, Артём Олегович|Артём Новичонок]], [[Kondopoga]], [[Russia]]).<ref name="Trigo-Rodriguez2013"/> The discovery was made using the {{convert|0.4|m|in|adj=on|sp=us}} [[reflecting telescope|reflector]] of the [[International Scientific Optical Network]] near [[Kislovodsk]], Russia and the automated asteroid-discovery program CoLiTec.<ref name="Remanzacco"/><ref name="NAS20121012"/> [[Precovery]] images by the [[Mount Lemmon Survey]] from 28 December 2011 and by [[Pan-STARRS]] from 28 January 2012 were quickly located.<ref name="MPEC2012-S63"/> Follow-up observations were made on 22 September by a team from Remanzacco Observatory in Italy using the [[iTelescope]] network.<ref name="Remanzacco"/><ref name="universetoday1"/> The discovery was announced by the [[Minor Planet Center]] on 24 September.<ref name="MPEC2012-S63"/> Observations by [[Swift Gamma-Ray Burst Mission|SWIFT]] suggest that C/2012 S1's [[comet nucleus|nucleus]] is around {{convert|5|km|sp=us}} in diameter.<ref name="Swift"/>


This comet makes me so hard oh my god
==Orbit==
C/2012 S1 will come to [[Apsis|perihelion]] (closest approach to the Sun) on 28 November 2013 at a distance of {{convert|0.0124|AU|km mi|abbr=on|lk=on}} from the center point of the Sun.<ref name="MPEC2013-S75"/> Accounting for the [[solar radius]] of {{convert|695500|km|mi|abbr=on}}, C/2012 S1 will pass approximately {{convert|1165000|km|mi|abbr=on}} above the Sun's surface.<ref name="Guardian20131013" /> Its [[Hyperbolic trajectory|trajectory appears hyperbolic]], which suggests that it is a dynamically new comet coming freshly from the [[Oort cloud]].<ref name="astronomynow1"/><ref name="newscientist1"/> On its closest approach, C/2012 S1 passed about {{convert|0.07248|AU|km mi|abbr=on|lk=off}} from Mars on 1 October 2013, and it will pass about {{convert|0.4292|AU|km mi|abbr=on|lk=off}} from Earth on 26 December 2013.<ref name="jpl-close"/>
C/2012 S1 will come to [[Apsis|perihelion]] (closest approach to the Sun) on 28 November 2013 at a distance of {{convert|0.0124|AU|km mi|abbr=on|lk=on}} from the center point of the Sun.<ref name="MPEC2013-S75"/> Accounting for the [[solar radius]] of {{convert|695500|km|mi|abbr=on}}, C/2012 S1 will pass approximately {{convert|1165000|km|mi|abbr=on}} above the Sun's surface.<ref name="Guardian20131013" /> Its [[Hyperbolic trajectory|trajectory appears hyperbolic]], which suggests that it is a dynamically new comet coming freshly from the [[Oort cloud]].<ref name="astronomynow1"/><ref name="newscientist1"/> On its closest approach, C/2012 S1 passed about {{convert|0.07248|AU|km mi|abbr=on|lk=off}} from Mars on 1 October 2013, and it will pass about {{convert|0.4292|AU|km mi|abbr=on|lk=off}} from Earth on 26 December 2013.<ref name="jpl-close"/>


Revision as of 17:15, 21 October 2013

C/2012 S1
C/2012 S1 as captured by Hubble Space Telescope on 10–11 April 2013
Discovery
Discovered byVitaly Nevsky and
Artyom Novichonok
at ISON-Kislovodsk, Russia
using a 0.4-m reflector (D00)[1]
Discovery date21 September 2012
Orbital characteristics
Epoch14 December 2013
(JD 2456640.5)[2]
Perihelion0.01244 AU (q)[2]
Eccentricity1.0000021[2]
Orbital periodejection trajectory (epoch 2050)[3]
Inclination62.39°[2]
Next perihelion28 November 2013[2]

C/2012 S1, also known as Comet ISON or Comet Nevski–Novichonok, is a sungrazing comet discovered on 21 September 2012 by Vitali Nevski (Виталий Невский, Vitebsk, Belarus) and Artyom Novichonok (Артём Новичонок, Kondopoga, Russia).[4] The discovery was made using the 0.4-meter (16 in) reflector of the International Scientific Optical Network near Kislovodsk, Russia and the automated asteroid-discovery program CoLiTec.[1][5] Precovery images by the Mount Lemmon Survey from 28 December 2011 and by Pan-STARRS from 28 January 2012 were quickly located.[6] Follow-up observations were made on 22 September by a team from Remanzacco Observatory in Italy using the iTelescope network.[1][7] The discovery was announced by the Minor Planet Center on 24 September.[6] Observations by SWIFT suggest that C/2012 S1's nucleus is around 5 kilometers (3.1 mi) in diameter.[8]

This comet makes me so hard oh my god C/2012 S1 will come to perihelion (closest approach to the Sun) on 28 November 2013 at a distance of 0.0124 AU (1,860,000 km; 1,150,000 mi) from the center point of the Sun.[2] Accounting for the solar radius of 695,500 km (432,200 mi), C/2012 S1 will pass approximately 1,165,000 km (724,000 mi) above the Sun's surface.[9] Its trajectory appears hyperbolic, which suggests that it is a dynamically new comet coming freshly from the Oort cloud.[10][11] On its closest approach, C/2012 S1 passed about 0.07248 AU (10,843,000 km; 6,737,000 mi) from Mars on 1 October 2013, and it will pass about 0.4292 AU (64,210,000 km; 39,900,000 mi) from Earth on 26 December 2013.[12]

Shortly after its discovery, similarities between the orbital elements of C/2012 S1 and the Great Comet of 1680 led to speculation that there might be a connection between them.[13] However, further observations of ISON showed that the two comets are not related.[14]

Earth will pass near the orbit of C/2012 S1 on 14–15 January 2014, well after the comet has passed, at which time micron-sized dust particles blown by the Sun's radiation may cause a meteor shower or noctilucent clouds.[15][16] However, both events are unlikely. Because Earth only passes near C/2012 S1's orbit, not actually through the tail, the chances that a meteor shower will occur are slim.[17] In addition, meteor showers from long period comets that make just one pass into the inner solar system are very rare, if ever recorded.[18] The possibility that small particles left behind on the orbital path—almost one hundred days after the nucleus has passed—could form noctilucent clouds is also slim. No such events are known to have taken place in the past under similar circumstances.[18]

Orbital position of C/2012 S1 on 11 December 2013 after perihelion.
Visualization of the orbit of comet ISON as it moves into the inner Solar System in 2013.

Brightness and visibility

The path of C/2012 S1 (ISON) from December 2012 through October 2013 as it passes through Gemini, Cancer, and Leo.

At the time of its discovery, C/2012 S1's apparent magnitude was approximately 18.8, far too dim to be seen with the naked eye, but bright enough to be imaged by amateurs with large telescopes.[19][20] It then followed the pattern of most comets and increased gradually in brightness on approach to the Sun.

From 5 June to 29 August 2013, C/2012 S1 had an elongation less than 30 degrees from the Sun.[21] The Spitzer Space Telescope observed C/2012 S1 on 13 June and estimated carbon dioxide production at about 1 million kilograms (2.2 million pounds) per day.[22] Amateur astronomer Bruce Gary recovered it on 12 August 2013 when it was 6 degrees above the horizon and 19 degrees from the Sun.[23] Due to it brightening more slowly than predicted, the comet only became visible through small telescopes during early October 2013.[24] C/2012 S1 is not expected to reach the naked eye magnitude of 6 until November,[21][25] and may not be observable by the general public until it brightens to about magnitude 4.[24] Assuming it survives perihelion passage, it may be visible to the naked eye until early January 2014.[10][20]

On 29 September 2013, the Mars Reconnaissance Orbiter (MRO) detected C/2012 S1.[26] In October, C/2012 S1 will pass through the constellation Leo, passing near Leo's brightest star Regulus and then passing near Mars in the night sky, and these brighter objects might make C/2012 S1 easier to locate.[19] STEREO should be able to view it around 10 October.[27] In November, when C/2012 S1 is brighter, it will sweep past another bright star in our sky, Spica in the constellation Virgo, and another planet, Saturn.[28] SOHO will be able to view C/2012 S1 starting 27 November.[27] Around the time it reaches perihelion on 28 November, it may become extremely bright if it remains intact, probably reaching a negative magnitude.[note 1][7] 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. Originally media sources predicted it might become brighter than the full Moon,[10][11] but based on more recent observations, it is only expected to reach around apparent magnitude −3 to −5, about the same brightness as Venus.[25][29] In comparison, the brightest comet since 1935 was Comet Ikeya–Seki in 1965 at magnitude −10, which was much brighter than Venus.[30]

Comet ISON, imaged by the Hubble Space Telescope on 10 April 2013—near Jupiter's orbit;[31] also, enhanced (coma model ratio) version.

C/2012 S1 is expected to be brightest around the time it is closest to the Sun; however, it may be less than 1° from the Sun at its closest, making it difficult to see against the Sun's glare.[32] In December, C/2012 S1 will be growing dimmer, but, assuming that it remains intact, it will be visible from both hemispheres of Earth, possibly with a long tail.[19] C/2012 S1 will be well placed for observers in the northern hemisphere during mid to late December 2013.[33] After perihelion, it will move north on the celestial sphere, passing within two degrees of Polaris on 8 January.[20]

In a February 2013 study, 1,897 observations were used to create a light curve. The resulting plot showed C/2012 S1 increasing its brightness relatively quickly at R+4.35.[Unit?][34] If this had continued to perihelion, C/2012 S1 would have reached magnitude −17, brighter than the full moon. However, it has since exhibited a "slowdown event", like the ones exhibited by many other Oort cloud comets, among them C/2011 L4. Therefore, C/2012 S1's brightness will increase less quickly than predicted and it will not become as bright as expected. Recent observations of C/2012 S1 suggest that, even if it remains intact, it may only brighten to about magnitude −6.[29] It has been determined that this is a "baby comet" (i.e. an object with a photometric age less than four comet years).[34] The temperature at perihelion has been calculated to reach 2,700 °C (4,890 °F), sufficient to melt iron. Additionally, it will be within the Roche limit, meaning it might disintegrate due to the Sun's gravity.

Comet C/2012 S1 (ISON) seen from the University of London Observatory on 10 October 2013, as it passes through the constellation of Leo

Name

The comet's formal designation is C/2012 S1. The "C" indicates that it is non-periodic, followed by the year of discovery. The "S" represents the half-month of discovery—in the case of C/2012 S1, the second half of September—and the number "1" shows that this was the first comet found in that half month.[35] The addition of "(ISON)" after its name merely identifies the organization where its discovery was made, the Russia-based International Scientific Optical Network. If the same organization had discovered a similar, but unrelated comet one day later, that one would have been named "C/2012 S2 (ISON)". Nevertheless, media sources have taken to referring to C/2012 S1 by its location of discovery,[36][37][38] and consequently, this name will likely persist in use even though it may cause confusion with later discoveries made by the ISON organization. The names of famous short-period comets usually identify the astronomers who discovered them or clearly identified them as a periodic comet, such as Halley's Comet or Comet Swift–Tuttle. If that convention had been followed, "Comet ISON" would be referred to instead as Comet Nevski–Novichonok or C/2012 S1 (Nevski–Novichonok).

Media coverage

After it was discovered in 2012, some media sources called C/2012 S1 the "Comet of the Century" and speculated that the comet might outshine the full Moon. An Astronomy Now columnist wrote in September 2012 that "if predictions hold true then C/2012 S1 will certainly be one of the greatest comets in human history."[10] As recently as October 2013, a Daily Mail columnist described C/2012 S1 as "the Comet of the Century" and said it was "hoped to be 15 times brighter than the Moon."[39]

Some scientists have criticized the media's coverage. Astronomer Karl Battams stated in July 2013 that "Few serious astronomers and cometary scientists have ever felt ISON would be 'brighter than the full Moon'. ... That's entirely the media's term, and we've been saying this for months, that none of us in the [Comet ISON Observing Campaign] foresee ISON getting that bright, and never have done so."[40]

Notes

  1. ^ Astronomical magnitudes decrease as brightness increases, from large positive values, through zero, to negative values for very bright objects.

References

  1. ^ a b c Guido, Ernesto; Sostero, Giovanni; Howes, Nick (24 September 2012). "New Comet: C/2012 S1 (ISON)". Associazione Friulana di Astronomia e Meteorologia. Retrieved 24 September 2012.
  2. ^ a b c d e f "MPEC 2013-S75: Observations and Orbits of Comets". IAU Minor Planet Center. 30 September 2013. Retrieved 1 October 2013.
  3. ^ Horizons output. "Barycentric Osculating Orbital Elements for Comet C/2012 S1 (ISON)". NASA.gov. Retrieved 25 November 2012. (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)
  4. ^ Trigo-Rodríguez, J. M.; Meech, K. J.; Rodriguez, D.; Sánchez, A.; Lacruz, J.; Riesen, T. E. (2013). Post-discovery Photometric Follow-up of Sungrazing Comet C/2012 S1 ISON (PDF). 44th Lunar and Planetary Science Conference. 18–22 March 2013. The Woodlands, Texas. #1576.
  5. ^ "Open the Great Comet Comet C/2012 S1 (ISON)". Neoastrasoft.com. 12 October 2012. Retrieved 11 September 2013.
  6. ^ a b "MPEC 2012-S63: Comet C/2012 S1 (ISON)". IAU Minor Planet Center. 24 September 2012. CK12S010. Retrieved 24 September 2012.
  7. ^ a b Atkinson, Nancy (25 September 2012). "New 'Sun-Skirting' Comet Could Provide Dazzling Display in 2013". Universe Today. Retrieved 28 September 2012.
  8. ^ Reddy, Francis (29 March 2013). "NASA's Swift Sizes Up Comet ISON". NASA.gov. Retrieved 23 April 2013.
  9. ^ Pickup, Alan (13 October 2013). "Starwatch: The brightening of ISON". The Guardian. Retrieved 16 October 2013.
  10. ^ a b c d Grego, Peter (25 September 2012). "New comet might blaze brighter than the full Moon". Astronomy Now. Retrieved 28 September 2012.
  11. ^ a b Hecht, Jeff (25 September 2012). "Newly spotted comet may outshine the full moon". New Scientist. Retrieved 28 September 2012.
  12. ^ "JPL Close-Approach Data: C/2012 S1 (ISON)". NASA.gov. 15 November 2012. Retrieved 25 November 2012.
  13. ^ Bortle, J. (24 September 2012). "Re: C/2012 S1 (ISON), Some Further Thoughts". comets-ml (Mailing list). Yahoo! Groups. Retrieved 5 October 2012. {{cite mailing list}}: Unknown parameter |mailinglist= ignored (|mailing-list= suggested) (help)
  14. ^ "Let History Be Our Guide?". Comet ISON Observing Campaign (COIC). 22 July 2013. Retrieved 2 August 2013.
  15. ^ King, Bob (19 October 2012). "Wassup with comets Hergenrother, L4 PanSTARRS and S1 ISON". Astro Bob. Areavoices.com. Retrieved 1 January 2013.
  16. ^ Phillips, Tony (19 April 2013). "Comet ISON Meteor Shower". NASA.gov. Archived from the original on 21 September 2013. Retrieved 23 April 2013.
  17. ^ Sekhar, A.; Asher, D. J. (11 October 2013). "Meteor showers on Earth from sungrazing comets" (PDF). Monthly Notices of the Royal Astronomical Society. arXiv:1310.3171.
  18. ^ a b "Comet ISON - Latest Updates, FAQ and Viewing Guide". Nightskyinfo.com. Retrieved 22 July 2013.
  19. ^ a b c Rao, Joe (25 September 2012). "Newfound Comet Could Look Spectacular in 2013". Space.com. Retrieved 28 September 2012.
  20. ^ a b c Bakich, Michael E. (25 September 2012). "Comet ISON will light up the sky". Astronomy. Retrieved 28 September 2012.
  21. ^ a b "Elements and Ephemeris for C/2012 S1 (ISON)". IAU Minor Planet Center. Retrieved 23 April 2013.
  22. ^ "NASA's Spitzer Observes Gas Emission From Comet ISON". NASA. 23 July 2013. Retrieved 1 August 2013.
  23. ^ Gary, Bruce (12 August 2013). "Comet ISON Observations by an Amateur Observer: Recovery Observation". BruceGary.net. Retrieved 4 October 2013.
  24. ^ a b Dickinson, David (23 September 2013). "Comet ISON: A Viewing Guide from Now to Perihelion". Universe Today. Retrieved 4 October 2013.
  25. ^ a b Bortle, John (13 June 2013). "Comet ISON approaches". Sky & Telescope. Retrieved 14 June 2013.
  26. ^ Delamere, Alan; McEwen, Alfred. "First HiRISE Images of Comet ISON". University of Arizona (HiRISE). Retrieved 2 October 2013.
  27. ^ a b "Anticipated STEREO observations of Comet ISON". NASA STEREO Science Center. 27 February 2013. Retrieved 28 April 2013.
  28. ^ Eagle, Dave (2012). "Two Bright Comets for 2013?". Eagleseye.me.uk. Retrieved 2 January 2013.
  29. ^ a b "ISON Updates from the CIOC". Sungrazing Comets. U.S. Navy. Retrieved 21 July 2013.
  30. ^ "Brightest comets seen since 1935". International Comet Quarterly. Retrieved 28 September 2012.
  31. ^ "Hubble captures Comet ISON". SpaceTelescope.org. 24 April 2013. Retrieved 30 April 2013.
  32. ^ Beatty, Kelly (27 September 2012). "A "Dream Comet" Heading Our Way?". Sky & Telescope. Retrieved 28 September 2012.
  33. ^ Dickinson, David (25 September 2012). "Will we have a Christmas comet in 2013?". Canada.com. Retrieved 30 September 2012.
  34. ^ a b Ferrín, Ignacio (2013). "Secular Light Curves of Comets C/2011 L4 Panstarrs and C/2012 S1 ISON Compared to 1P/Halley". arXiv:1302.4621 [astro-ph]. {{cite arXiv}}: Unknown parameter |version= ignored (help)
  35. ^ "Comet ISON - Latest Updates, FAQ and Viewing Guide". Nightskyinfo.com. Retrieved 18 June 2013.
  36. ^ Rannals, Lee (27 December 2012). "Brilliant Comet, Brighter than Full Moon, Making Debut in 2013". RedOrbit.com. Retrieved 29 December 2012.
  37. ^ Whitehouse, David (27 December 2012). "'Brighter than a full moon': The biggest star of 2013... could be Ison - the comet of the century". The Independent. Retrieved 29 December 2012.
  38. ^ "New Year promises treat for stargazers". The Times of India. 29 December 2012. Retrieved 29 December 2012.
  39. ^ Griffiths, Sarah (18 October 2013). "Dazzling 'comet of the century' is still intact! Icy ball 15 times brighter than the moon might be visible in December - IF it survives". Daily Mail. Retrieved 20 October 2013.
  40. ^ Atkinson, Nancy (30 July 2013). "Rumors of Comet ISON 'Fizzling' May be Greatly Exaggerated". Universe Today. Retrieved 20 October 2013.
Wikimedia Commons has media related to C/2012 S1.
Media
Minor Planet Electronic Circulars
  • MPEC 2013-S75 (2013 Sep 30 : 4308 obs : Epoch 2013 Dec 14 e=1.0000020 q=0.0124441)
  • MPEC 2013-S08 (2013 Sep 16 : 3997 obs : Epoch 2013 Dec 14 e=1.0000019 q=0.0124442)
  • MPEC 2013-R59 (2013 Sep 6 : 3897 obs : Epoch 2013 Dec 14 e=1.0000019 q=0.0124441)
  • MPEC 2013-H38 (2013 Apr 23 : 3442 obs : Epoch 2013 Dec 14 e=1.0000020 q=0.0124437)
  • MPEC 2013-G31 (2013 Apr 9 : 3307 obs : Epoch 2013 Dec 14 e=1.0000021 q=0.0124435)
  • MPEC 2013-F47 (2013 Mar 25 : 3121 obs : Epoch 2013 Dec 14 e=1.0000022 q=0.0124434)
  • MPEC 2013-F20 (2013 Mar 18 : 3047 obs : Epoch 2013 Dec 14 e=1.0000022 q=0.0124434)
  • MPEC 2013-E40 (2013 Mar 9 : 2799 obs : Epoch 2013 Dec 14 e=1.0000022 q=0.0124437)
  • MPEC 2013-D50 (2013 Feb 23 : 2372 obs : Epoch 2013 Dec 14 e=1.0000020 q=0.0124436)
  • MPEC 2013-C52 (2013 Feb 12 : 1999 obs : Epoch 2013 Dec 14 e=1.0000019 q=0.0124439)
  • MPEC 2013-A85 (2013 Jan 14 : 1418 obs : Epoch 2013 Dec 14 e=1.0000016 q=0.0124445)
  • MPEC 2012-Y30 (2012 Dec 26 : 1000 obs : Epoch 2013 Dec 14 e=1.0000015 q=0.0124443)
  • MPEC 2012-X53 (2012 Dec 11 : 812 obs : Epoch 2013 Dec 14 e=1.0000014 q=0.0124453)
  • MPEC 2012-W54 (2012 Nov 27 : 706 obs : Epoch 2013 Dec 14 e=1.0000014 q=0.0124475)
  • MPEC 2012-V101 (2012 Nov 15 : 538 obs)
  • MPEC 2012-U109 (2012 Oct 26 : 418 obs : Epoch 2013 Dec 14 e=1.0000013 q=0.0124484)
  • MPEC 2012-T73 (2012 Oct 12 : 272 obs : Epoch 2013 Dec 14 e=1.0000008 q=0.0124472)
  • MPEC 2012-T08 (2012 Oct 3 : 163 obs : Epoch 2013 Dec 14 e=1.0000013 : (1/a)_orig = +0.00005808, (1/a)_fut = +0.00000785)
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