C / 2010 X1 (Elenin)
| C / 2010 X1 (Elenin) [i] | |
|---|---|
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| C / 2010 X1 on August 1, 2011 | |
| Properties of the orbit ( animation ) | |
| Orbit type |
hyperbolic s. Cape. Orbit |
| Numerical eccentricity | 1.000068 |
| Perihelion | 0.482 AU |
| Inclination of the orbit plane | 1.8 ° |
| Perihelion | September 10, 2011 |
| Orbital velocity in the perihelion | 60.6 km / s |
| history | |
| Explorer | Leonid Elenin |
| Date of discovery | December 10, 2010 |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 2010 X1 (Elenin) was a comet that could be observed in 2010 and 2011. As it approached the sun , it dissolved at the beginning of September 2011 shortly before passing through the point of its orbit closest to the sun .
Discovery and observation
The comet was discovered in Russia by L. Elenin on four images taken on December 10, 2010 with a 45 cm astrograph from the International Scientific Optical Network (ISON) in New Mexico . He stated the brightness to be about 19.5 mag. Within half a day, the discovery was confirmed by further observations. At that time, the comet was still about 4.2 AU from the Sun.
An improved orbit calculation was made in the second half of December, and the comet continued to be observed by several observatories . By the beginning of April 2011 the brightness had increased to around 16.5 mag, on April 5th the comet could be observed visually for the first time with a telescope in Spain at 15 mag. By the end of June the brightness had risen to 10.5 mag, which was brighter than expected. Since the comet was now moving further into the southern sky , it could no longer be seen from the northern hemisphere .
It was observed further in the southern hemisphere , and its brightness initially rose to around 8 mag on August 21. Within the next 24 hours, however, the brightness had already decreased by half a magnitude. At the end of August a brightness of 9.4 mag was given and the comet appeared blurred. In the days that followed, the comet could be observed to break up and finally disintegrate. On September 11th, only indistinct traces of him could be found.
Effects on the zeitgeist
The predicted approach of the comet to Earth in October 2011 was exaggerated in advance by some media and conspiracy theorists into a catastrophe scenario in connection with the alleged end of the world in 2012 .
Scientific evaluation
When the comet was about 3 AU from the Sun, it was examined with the BTA-6 telescope at the Zelenchuk Observatory . A mass loss of 6 kg / s was estimated. In the coma , molecules such as CN and C 3 could be detected and the gas production rate was determined.
The exact course of the development of the comet up to its dissolution was analyzed in detail. A radius of 0.6 km was derived for the core before its dissolution. After the disintegration, no fragments with a radius greater than 40 m were found. An increasingly unstable rotation , caused by the loss of mass, is considered to be the cause of the dissolution .
At the time when the comet should have passed Earth, the Herschel Space Telescope's PACS instrument was being searched for remains of it. However, no fragments with a diameter larger than 260 m and no bodies larger than one millimeter were found in the expanding dust cloud.
Orbit
For the comet, a temporary hyperbolic orbit could be determined from 2235 observation data over a period of 271 days , which was inclined by around 2 ° to the ecliptic . The comet's orbit was almost in the same plane as that of the planets . At the point closest to the Sun ( perihelion ), which the comet would have passed on September 10, 2011, it would have been about 72.2 million km from the Sun and would have moved between the orbits of Mercury and Venus . Already on December 20, 2008 it had passed Saturn very closely at a distance of about 2 ⅔ AU and on August 28, 2011 it had approached Venus to about 145.2 million km , it did not come notably close to Mercury and Mars .
If it hadn't disintegrated, it would have come closest to Earth on October 16 at a distance of about 0.23 AU / 34.9 million km. In addition, he would have the earth orbit on 18./19. October 2011 even approximated to a very small distance of 4.6 million km, which corresponds to almost 12 times the mean distance from earth to moon . The earth reached this point of its orbit only two weeks later around November 1st.
According to the orbital elements afflicted with a certain uncertainty , as they are specified in the JPL Small-Body Database and which take into account non-gravitational forces on the comet, one would obtain an elliptical characteristic with a long before the approach to the inner solar system for the original orbit Eccentricity of just under 1.0000, so its orbit was almost parabolic . With a semi-major axis of about 60,000 AU (about one light year ), its orbital period would have been in the range of over 10 million years. The comet then came out of the Oort cloud and possibly experienced its first passage through the inner solar system as a “dynamic young” comet. This could also explain its unexpected increase in brightness when approaching the sun and its decay due to internal instabilities.
In a study from 2013 Królikowska and Dybczyński were able to show, using 2104 observations of the comet, that the observed orbit of the comet can be described much better by a purely gravitational approach, i.e. without taking non-gravitational forces into account, if for The determination of the orbit parameters can only be used for observations up to the end of May 2010, i.e. before the comet showed the first signs of impending decay. They gave the corresponding track elements for this. They also determined values for the original shape of the orbit long before the passage through the inner solar system. You also get the result that the comet moved on an elliptical orbit before it approached the sun, albeit with a semi-major axis of about 41,500 AU and thus had an orbital period of about 8.5 million years (uncertainty ± 10%) . They were able to confirm that it came from the Oort cloud and that it can also be classified as "dynamic new", that is, it probably came near the sun for the first time.
In a further study from 2015, they were able to optimize the data somewhat by simulating the cometary dynamics with statistical methods while also taking into account the forces of attraction of the galactic disc and the galactic center, as well as gravitationally disruptive stars in the solar environment, but these additional effects only had one very little influence, so that the numerical values mentioned above could also be approximately confirmed here.
See also
Web links
- C / 2010 X1 (Elenin) Seiichi Yoshida's Home Page (English)
Individual evidence
- ^ GW Kronk: C / 2010 X1 (Elenin). In: Gary W. Kronk's Cometography. Retrieved July 19, 2020 .
- ↑ F. Freistetter: Danger from Comet Elenin? In: ScienceBlogs. Konradin Medien GmbH, February 28, 2011, accessed on July 19, 2020 .
- ↑ PP Korsun, IV Kulyk, AV Moiseev, VL Afanasiev: Comet C / 2010X1 (Elenin). Unrealized expectations. In: Astrophysical Bulletin. Volume 67, 2012, pp. 414-424 doi: 10.1134 / S1990341312040050 .
- ^ J. Li, D. Jewitt: Disappearance of Comet C / 2010 X1 (Elenin): Gone With a Whimper, Not a Bang. In: The Astronomical Journal. Volume 149, No. 4, 2015, pp. 1–13 doi: 10.1088 / 0004-6256 / 149/4/133 . ( PDF; 1.52 MB )
- ↑ MR Kidger, B. Altieri, Th. Müller, J. Gracia: A Search for the Far-Infrared Ghost of C / 2010 X1 (Elenin) with Herschel. In: Earth, Moon, and Planets. Volume 117, 2016, pp. 101-108 doi: 10.1007 / s11038-016-9484-3 .
- ↑ C / 2010 X1 (Elenin) in the Small-Body Database of the Jet Propulsion Laboratory (English).
- ↑ A. Vitagliano: SOLEX 12.1. Retrieved July 9, 2020 .
- ↑ C / 2010 X1 Elenin. Solar System Dynamics & Planetology Group, 2013, accessed July 24, 2020 .
- ↑ M. Królikowska, PA Dybczyński: Near-parabolic comets observed in 2006–2010. The individualized approach to 1 / a-determination and the new distribution of original and future orbits. In: Monthly Notices of the Royal Astronomical Society. Volume 435, No. 1, 2013, pp. 440–459 doi: 10.1093 / mnras / stt1313 . ( PDF; 1.77 MB )
- ↑ PA Dybczyński, M. Królikowska: Near-parabolic comets observed in 2006–2010 - II. Their past and future motion under the influence of the Galaxy field and known nearby stars. In: Monthly Notices of the Royal Astronomical Society. Volume 448, No. 1, 2015, pp. 588-600 doi: 10.1093 / mnras / stv013 . ( PDF; 967 kB )