Discovery | |
---|---|
Discovered by | Vladimir Bezugly SOHO |
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 |
Earth MOID | 0.543 AU |
Jupiter MOID | 2.982 AU |
Comet C/2012 E2 (SWAN) was a Kreutz group sungrazing comet discovered by Vladimir Bezugly in publicly available images taken by the SWAN instrument (Solar Wind ANisotropies) on board the SOHO spacecraft. It is recognized for being the first Kreutz 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 Comet C/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. [2]
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 of SOHO's LASCO telescopes on March 13, there too the comet did not appear exceptionally bright, it was fainter in comparison to Comet C/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 survive perihelion. SECCHI's COR instruments on both STEREO spacecraft also observed the comet's final moments. [3] [2] [4]
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. [2] No ground-based observations of the comet were available.
Due to a short 2-day observation arc, the long-term trajectory of the comet is poorly constrained. The orbital period is unknown with an orbital inclination of 144 degrees. [1]
The Solar and Heliospheric Observatory (SOHO) is a European Space Agency (ESA) spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on 2 December 1995, to study the Sun. It has also discovered over 5,000 comets. It began normal operations in May 1996. It is a joint project between the European Space Agency (ESA) and NASA. SOHO was part of the International Solar Terrestrial Physics Program (ISTP). Originally planned as a two-year mission, SOHO continues to operate after almost 29 years in space; the mission has been extended until the end of 2025, subject to review and confirmation by ESA's Science Programme Committee.
A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation.
The Great Comet of 1843, formally designated C/1843 D1 and 1843 I, was a long-period comet which became very bright in March 1843. It was discovered on February 5, 1843, and rapidly brightened to become a great comet. It was a member of the Kreutz Sungrazers, a family of comets resulting from the breakup of a parent comet into multiple fragments in about 1106. These comets pass extremely close to the surface of the Sun—within a few solar radii—and often become very bright as a result.
The Great Comet of 1882 formally designated C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882. It was a member of the Kreutz Sungrazers, a family of comets which pass within 1 R☉ of the Sun's photosphere at perihelion. The comet was bright enough to be visible next to the Sun in the daytime sky at its perihelion. The comet made its closest approach to Earth on 16 September 1882 at 0.99 AU and then came to perihelion the next day on 17 September.
The Kreutz sungrazers are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. At the far extreme of their orbits, aphelion, Kreutz sungrazers can be a hundred times farther from the Sun than the Earth is, while their distance of closest approach can be less than twice the Sun's radius. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first demonstrated that they were related. These sungrazers make their way from the distant outer Solar System to the inner Solar System, to their perihelion point near the Sun, and then leave the inner Solar System in their return trip to their aphelion.
Comet White–Ortiz–Bolelli was a bright comet which appeared in 1970. It was a member of the Kreutz Sungrazers, a family of comets which resulted from the break-up of a large parent comet several centuries ago. It was already easily visible to the naked eye when first discovered, and reached a maximum apparent magnitude of +1.
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Comet 96P/Machholz or 96P/Machholz 1 is a short-period sungrazing comet discovered on May 12, 1986, by amateur astronomer Donald Machholz on Loma Prieta peak, in central California using 130 millimetres (5.1 in) binoculars. On June 6, 1986, 96P/Machholz passed 0.404 AU from the Earth. 96P/Machholz last came to perihelion on January 31, 2023. The comet has an estimated diameter of around 6.4 km (4.0 mi).
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The Great Southern Comet of 1887, or C/1887 B1 using its International Astronomical Union (IAU) designation, was a bright comet seen from the Southern Hemisphere during January 1887. Later calculations indicated it to be part of the Kreutz Sungrazing group. It came to perihelion on 11 January 1877 at a distance of 0.00483 AU (723 thousand km) with a velocity of 606.1 km/s. Since the Sun has a radius of 696000 km, the comet passed about 27000 km from the surface of the Sun.
Comet Lovejoy, formally designated C/2011 W3 (Lovejoy), is a long-period comet and Kreutz sungrazer. It was discovered in November 2011 by Australian amateur astronomer Terry Lovejoy. The comet's perihelion took it through the Sun's corona on 16 December 2011, after which it emerged intact, though greatly impacted by the event.
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