| Discovery | |
|---|---|
| Discovered by | SOHO Vladimir Bezugly |
| Discovery date | 8 March 2012 |
| Orbital characteristics[1] | |
| Epoch | 13 March 2012 (JD 2455999.5) |
| Observation arc | 2 days |
| Number of observations | 43 |
| Perihelion | 0.0069 AU |
| Semi-major axis | –14.169 AU |
| Eccentricity | 1.0005 |
| Inclination | 144.431° |
| 6.576° | |
| Argument of periapsis | 82.412° |
| Mean anomaly | –0.037° |
| Last perihelion | 15 March 2012 |
| EarthMOID | 0.543 AU |
| JupiterMOID | 2.982 AU |
| Physical characteristics[2] | |
Mean diameter | 0.08–0.68 km (0.050–0.423 mi) |
| 1.0 (2012 apparition) | |
CometC/2012 E2 (SWAN) was aKreutz groupsungrazing comet discovered by Vladimir Bezugly in publicly available images taken by theSWAN instrument (Solar Wind ANisotropies) on board theSOHO spacecraft. It is recognized for being the firstKreutz sungrazer observed in SWAN imagery.
On March 8, 2012, Ukrainian amateur astronomer Vladimir Bezugly reported an unknown comet in 3 images taken by the SWAN instrument on board the SOHO spacecraft. Further study of this object revealed that it was a Kreutz group sungrazer with a perihelion date on March 15, 2012. This was particularly interesting because no Kreutz sungrazer had ever been bright enough to be observed by the SWAN cameras, not even CometC/2011 W3 (Lovejoy) which was visible to the naked-eye three months earlier. This meant that Comet SWAN had a chance of being an exceptionally bright comet.[3]
The SECCHI HI1 camera on board the STEREO-B spacecraft was the first to observe the comet after the SWAN instrument. It entered the field of view on March 11 and appeared reasonably bright, though not as bright as it could have been.
The comet entered the visibility ofSOHO's LASCO telescopes on March 13, there too the comet did not appear exceptionally bright, it was fainter in comparison to CometC/2011 W3 (Lovejoy) at this stage of its orbit. Though it certainly appeared brighter than most sungrazing comets of the Kreutz group. It reached a maximum apparent brightness of mag +1 before it declined in brightness due to disintegration. The comet did not surviveperihelion.
SECCHI's COR instruments on bothSTEREO spacecraft also observed the comet's final moments.[4][3][5]
The reason of the comet's brightness in SWAN remains unknown, though it is thought that the comet experienced an outburst a few days before discovery which rendered it much brighter than it was otherwise.[3] No ground-based observations of the comet were available.
Due to a short 2-dayobservation arc, the long-term trajectory of the comet is poorly constrained. Theorbital period is unknown with anorbital inclination of 144 degrees.[1]
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