C/2010 X1 (Elenin)

C/2010 X1 (Elenin)

Image of comet Elenin on 2011 August 19
Copyright © 2011 by Terry Lovejoy (Australia)

T. Lovejoy obtained this image of the comet on 2011 August 19. He was using a 20-cm Hyperstar reflector and a QHY9 CCD camera. Seventeen 30-second exposures were combined to create this image, which revealed the comet's tail was about a degree long. The comet was then at low altitude and some twilight was present.

Discovery

Leonid Elenin (Lyubertsy, Russia) discovered this comet on four images obtained during the period of 2010 December 10.42-10.46 using the 45-cm astrograph and a CCD camera at the International Scientific Optical Network's robotic observatory near Mayhill, New Mexico. The magnitude was given as 19.5-19.6. The first confirmation came from A. Sergeyev and A. Novichonok(Majdanak Observatory, Uzbekistan), when they obtained four images during December 10.99-11.00 using the 1.5-m reflector and a CCD camera. The magnitude was given as 19.1 and the comet was described as a "teardrop-shaped, very diffuse coma." This coma was 6 arc seconds across and exhibited a nuclear condensation of magnitude 20.7, while a tail extended 10-12 arc seconds toward PA 298 degrees.

Historical Highlights

The first parabolic orbit was calculated by G. V. Williams on 2010 December 17. He took 33 positions from the period spanning 2010 December 10-12 and determined the perihelion date as 2010 April 1.81. The perihelion distance was given as 5.15 AU. Williams added, "It is possible that this comet is of short period." The Minor Planet Center released a revised orbit on December 18 that showed a quite different orbit. The perihelion date was given as 2011 September 5.47, while the perihelion distance was 0.45 AU. This was based on 57 positions from the period of December 10-17. This orbit was confirmed on December 24. We now know that the comet is moving in a very long-period orbit, with a perihelion date of 2011 September 10.75, a perihelion date of 0.48 AU, and a period of about one million years.

Several observatories kept the comet under observation through the remainder of 2010, as the comet slightly brightened to about magnitude 19.

The comet has been well observed by observatories from the beginning of 2011 to the present, with visual observers finally picking up the comet on April 5. The comet began the year at a nuclear magnitude of about 19, and brightened to about 18 by February 1, 17 by March 1, and 16.5 by April 1. The January and February observations typically revealed a coma about 0.3' across and a tail extending 0.3-0.5'. The first visual observation was acquired by J. J. Gonzalez (Alto del Castro - Aralla, Leon, Spain) on April 5. He was using his 20-cm reflector, giving the magnitude as 14.9 and noting a strongly condensed coma 0.3' across. As the comet continued to head southward, Gonzalez reported magnitudes of 13.7 on April 26, 13.2 on May 22, and 10.5 on June 25. During the same period, he noted the coma diameter was 1.3' in April, 1.2' in May, and 2.5' in June. Gonzalez noted on June 25 that the comet was "brighter than expected" and that the larger coma represented the dimension of a faint outer region that had become visible. Another active observer was J. Cerny. Observing from locations in the Czech Republic and Croatia, he followed the comet from late April and throughout May using a 35-cm reflector. Cerny indicated the magnitude generally brightened from 14.8 on April 22 and 23, to 13.0 by May 31, while the coma increased from 0.8' to 1.5' during the same period.

The comet's location in the sky made it increasingly more difficult for observers in the Northern Hemisphere and no observations were made after June. Observers in the Southern Hemisphere picked the comet up near the beginning of June, with A. Amorim (Florianopolic, Brazil) spotting the comet with his 20-cm reflector on the 4th. He gave the magnitude as 13.4. The comet was not observed during the first half of June; however, starting on June 21, M. Mattiazzo (Castlemaine, Victoria, Australia) began following the comet. On that date he reported the magnitude as 10.5, using his 20-cm reflector and noted a coma 3' across. Mattiazzo said the comet brightened to 10.0 by the 28th and then he switched to observing with his 25x100 binoculars and found the comet at magnitude 9.5 by July 30. Although Mattiazzo was not the most prolific observer during August, his observations were the only ones to span all of August (at least as of the early September writing of this). His estimates of the comet's brightness also closely represented the estimates of all other observers. Continuing the use his large binoculars, Mattiazzo reported a magnitude of 9.0 on the 7th, 8.2 on the 17th, and 8.1 on the 19th. His next observation on the 22nd revealed the comet had dimmed to magnitude 8.8 and it was at 8.9 on the 23rd. Another Australian observer, D. A. J. Seargent (Cowra, New South Wales, Australia) had seen the comet using his 25x100 binoculars on August 21 and had noted a magnitude of 8.1. This indicates that the comet faded by over half a magnitude in the 24 hours between the time of Seargent's August 21st observation and Mattiazzo's observation on August 22. Amorim saw the comet on August 31 using an 8-cm reflector and gave the magnitude as 9.4. He noted that the comet appeared very slightly condensed. Mattiazzo also acquired a fine series of images (see below) that revealed the comet was breaking up. Mattiazzo continued to follow the comet into September, but it eventually vanished.

Additional Images
Image of comet Elenin on 2011 February 26
Copyright © 2011 by B. Hausler (Maidbronn, Germany)

Copyright © 2011 by M. Mobberly (England)

Copyright © 2011 by Alfons Diepvens (Balen, Belgium)

A. Diepvens obtained this image of the comet on 2011 March 7.96. He was using a 20-cm refractor and a Canon 7D digital camera. This image was a 57 minute exposure at ISO 1600.

Image of comet Elenin on 2011 June 30
Copyright © 2011 by E. Bryssinck (Belgium)

Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 August 3.5. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Twenty 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 August 19
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 August 19.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Forty 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 August 22
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 August 22.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Forty 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 August 23
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 August 23.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Forty 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 August 27
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 August 27.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Fifteen 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 August 29
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 August 29.38. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 September 1
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 September 1.38. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 September 2
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 September 2.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 September 6
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 September 6.38. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image.

Image of comet Elenin on 2011 September 11
Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia)

M. Mattiazzo obtained this image of the comet on 2011 September 11.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Twenty 10-second exposures were combined to produce this image. The comet was only 8 degrees above the horizon.

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C/2010 X1 (Elenin)


Copyright © 2011 by Terry Lovejoy (Australia) T. Lovejoy obtained this image of the comet on 2011 August 19. He was using a 20-cm Hyperstar reflector and a QHY9 CCD camera. Seventeen 30-second exposures were combined to create this image, which revealed the comet's tail was about a degree long. The comet was then at low altitude and some twilight was present. Discovery Leonid Elenin (Lyubertsy, Russia) discovered this comet on four images obtained during the period of 2010 December 10.42-10.46 using the 45-cm astrograph and a CCD camera at the International Scientific Optical Network's robotic observatory near Mayhill, New Mexico. The magnitude was given as 19.5-19.6. The first confirmation came from A. Sergeyev and A. Novichonok(Majdanak Observatory, Uzbekistan), when they obtained four images during December 10.99-11.00 using the 1.5-m reflector and a CCD camera. The magnitude was given as 19.1 and the comet was described as a "teardrop-shaped, very diffuse coma." This coma was 6 arc seconds across and exhibited a nuclear condensation of magnitude 20.7, while a tail extended 10-12 arc seconds toward PA 298 degrees. Historical Highlights The first parabolic orbit was calculated by G. V. Williams on 2010 December 17. He took 33 positions from the period spanning 2010 December 10-12 and determined the perihelion date as 2010 April 1.81. The perihelion distance was given as 5.15 AU. Williams added, "It is possible that this comet is of short period." The Minor Planet Center released a revised orbit on December 18 that showed a quite different orbit. The perihelion date was given as 2011 September 5.47, while the perihelion distance was 0.45 AU. This was based on 57 positions from the period of December 10-17. This orbit was confirmed on December 24. We now know that the comet is moving in a very long-period orbit, with a perihelion date of 2011 September 10.75, a perihelion date of 0.48 AU, and a period of about one million years. Several observatories kept the comet under observation through the remainder of 2010, as the comet slightly brightened to about magnitude 19. The comet has been well observed by observatories from the beginning of 2011 to the present, with visual observers finally picking up the comet on April 5. The comet began the year at a nuclear magnitude of about 19, and brightened to about 18 by February 1, 17 by March 1, and 16.5 by April 1. The January and February observations typically revealed a coma about 0.3' across and a tail extending 0.3-0.5'. The first visual observation was acquired by J. J. Gonzalez (Alto del Castro - Aralla, Leon, Spain) on April 5. He was using his 20-cm reflector, giving the magnitude as 14.9 and noting a strongly condensed coma 0.3' across. As the comet continued to head southward, Gonzalez reported magnitudes of 13.7 on April 26, 13.2 on May 22, and 10.5 on June 25. During the same period, he noted the coma diameter was 1.3' in April, 1.2' in May, and 2.5' in June. Gonzalez noted on June 25 that the comet was "brighter than expected" and that the larger coma represented the dimension of a faint outer region that had become visible. Another active observer was J. Cerny. Observing from locations in the Czech Republic and Croatia, he followed the comet from late April and throughout May using a 35-cm reflector. Cerny indicated the magnitude generally brightened from 14.8 on April 22 and 23, to 13.0 by May 31, while the coma increased from 0.8' to 1.5' during the same period. The comet's location in the sky made it increasingly more difficult for observers in the Northern Hemisphere and no observations were made after June. Observers in the Southern Hemisphere picked the comet up near the beginning of June, with A. Amorim (Florianopolic, Brazil) spotting the comet with his 20-cm reflector on the 4th. He gave the magnitude as 13.4. The comet was not observed during the first half of June; however, starting on June 21, M. Mattiazzo (Castlemaine, Victoria, Australia) began following the comet. On that date he reported the magnitude as 10.5, using his 20-cm reflector and noted a coma 3' across. Mattiazzo said the comet brightened to 10.0 by the 28th and then he switched to observing with his 25x100 binoculars and found the comet at magnitude 9.5 by July 30. Although Mattiazzo was not the most prolific observer during August, his observations were the only ones to span all of August (at least as of the early September writing of this). His estimates of the comet's brightness also closely represented the estimates of all other observers. Continuing the use his large binoculars, Mattiazzo reported a magnitude of 9.0 on the 7th, 8.2 on the 17th, and 8.1 on the 19th. His next observation on the 22nd revealed the comet had dimmed to magnitude 8.8 and it was at 8.9 on the 23rd. Another Australian observer, D. A. J. Seargent (Cowra, New South Wales, Australia) had seen the comet using his 25x100 binoculars on August 21 and had noted a magnitude of 8.1. This indicates that the comet faded by over half a magnitude in the 24 hours between the time of Seargent's August 21st observation and Mattiazzo's observation on August 22. Amorim saw the comet on August 31 using an 8-cm reflector and gave the magnitude as 9.4. He noted that the comet appeared very slightly condensed. Mattiazzo also acquired a fine series of images (see below) that revealed the comet was breaking up. Mattiazzo continued to follow the comet into September, but it eventually vanished. Additional Images Copyright © 2011 by B. Hausler (Maidbronn, Germany) Copyright © 2011 by M. Mobberly (England) Copyright © 2011 by Alfons Diepvens (Balen, Belgium) A. Diepvens obtained this image of the comet on 2011 March 7.96. He was using a 20-cm refractor and a Canon 7D digital camera. This image was a 57 minute exposure at ISO 1600. Copyright © 2011 by E. Bryssinck (Belgium) Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 August 3.5. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Twenty 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 August 19.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Forty 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 August 22.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Forty 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 August 23.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Forty 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 August 27.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Fifteen 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 August 29.38. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 September 1.38. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 September 2.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 September 6.38. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Ten 10-second exposures were combined to produce this image. Copyright © 2011 by Michael Mattiazzo (Castlemaine, Victoria, Australia) M. Mattiazzo obtained this image of the comet on 2011 September 11.39. He was using a Celestron Nexstar 28-cm reflector and a Starlight Express MX7c CCD camera. Twenty 10-second exposures were combined to produce this image. The comet was only 8 degrees above the horizon.
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