C / 2009 R1 (McNaught)
| C / 2009 R1 (McNaught) [i] | |
|---|---|
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| C / 2009 R1 on June 9, 2010 | |
| Properties of the orbit ( animation ) | |
| Orbit type |
hyperbolic s. Cape. Orbit |
| Numerical eccentricity | 1,00041 |
| Perihelion | 0.405 AU |
| Inclination of the orbit plane | 77.0 ° |
| Perihelion | July 2, 2010 |
| Orbital velocity in the perihelion | 66.2 km / s |
| history | |
| Explorer | Robert McNaught |
| Date of discovery | September 9, 2009 |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 2009 R1 (McNaught) is a comet that could be seen with the naked eye in 2010 .
Discovery and observation
The comet was discovered by RH McNaught at the Siding Spring Observatory in Australia on five images taken on September 9, 2009 with a 50 cm telescope . He gave the brightness to about 17.4 mag. Within a few hours, the discovery was confirmed by further observations. The comet was about 4.5 at this time AE from the sun away. The comet was subsequently found on several photos taken in Siding Spring on July 20th, August 1st and August 18th.
An initial orbit calculation by Brian Marsden already indicated that the comet could come close to the sun in July 2010 and thus become a fairly bright object. Several observatories continued to observe the comet . By the end of the year the brightness had grown to around 16 mag. When it reappeared for observers in the southern hemisphere at dawn in mid-March , the brightness was still only around 15 mag, but it then rose rapidly to brighter than 10 mag at the end of April.
The comet migrated further north and could be seen for the first time in the northern hemisphere in early May , and by the end of the month it had reached 7 mag. In June the brightness rose to around 5 mag and it could be seen with the naked eye. At the time it was still expected that the brightness would increase to 2 mag, even if the comet would be difficult to observe at dawn and dusk. However, it fell well short of expectations and was no brighter than 5 mag until it passed the sun.
After passing through the perihelion, the comet could no longer be found. Some observers reported its dissolution.
Scientific evaluation
With the 2 m telescope of the Pik Terskol Observatory in the Caucasus , the spectrum of cometary light was examined and emission lines of molecules such as C 2 , CN, CH, NH 2 and ions such as CO + and CH + were detected.
In June 2010, the radio telescope of the Crimean Observatory was used to study the gas production rate of the OH molecule as a function of the comet's distance from the sun.
Orbit
For the comet, a hyperbolic orbit could be determined from 765 observation data over a period of almost a year , which is inclined by around 77 ° to the ecliptic . The comet's orbit thus runs steeply against the planets of the planets . At the point closest to the Sun ( perihelion ), which the comet passed on July 2, 2010, it was about 60.6 million km from the Sun and was thus in the area of Mercury's orbit . Already on June 15, the closest approximation to the earth to about 1.13 AU / 169.8 million km had taken place. After passing through the perihelion, it may have approached Venus up to about 113.2 million km on July 5th and Mercury up to 22.5 million km on July 19th.
According to the orbit elements afflicted with a certain uncertainty , as they are given in the JPL Small-Body Database and which do not take into account non-gravitational forces on the comet, one would obtain both for the original orbit long before the approach to the inner solar system , as well as for the future orbit long after leaving the inner solar system, a hyperbolic characteristic for the comet's orbit, according to which it would have had an interstellar origin and would have left the solar system (if it had survived passing the sun) there again.
In a study from 2013, Królikowska and Dybczyński were able to show, using 792 observations of the comet, that the comet's orbit can be described much better if, in addition to the gravitational influences of all planets and the relativistic effects when flying close to the sun, it can be described non-gravitational forces on the comet can be taken into account through outgassing effects. They gave the corresponding track elements for this. They also determined values for the original and future shape of the orbit long before and after the passage through the inner solar system. They obtained the result that the comet was moving on an elliptical orbit with a semi-major axis of about 82,000 AU before it approached the sun and thus had an orbital period of about 24 million years (uncertainty ± 25%). With a high probability it did not have an interstellar origin, but came from the Oort cloud . They also classified the comet as "dynamic new," meaning that it was probably the first time it came near the Sun.
Even before approaching the sun, the comet had passed Uranus on June 27, 2004 at a distance of about 12 AU and on August 25, 2009 very close to Jupiter at a distance of only about 1 ¼ AU . If the comet had not dissolved in the vicinity of the sun, the gravitational pull of these planets in particular, as well as a further approach to Saturn on August 9, 2010 to a distance of about 9 AU, would most likely have the semiaxis of its orbit around 5900 AU and his Orbit period has been reduced to about 450,000 years. This information is very imprecise, however, because no observations of the comet are available after it has passed the sun, so that the orbital time could also have been considerably shorter or the orbit could have become slightly hyperbolic.
In another study from 2015, they were able to optimize the data somewhat by simulating the comet dynamics with statistical methods , taking into account the forces of attraction of the galactic disk and the galactic center, as well as gravitationally disruptive stars in the sun's surroundings, so that the comet was originally rather moved on an elliptical orbit with a semi-major axis of about 77,000 AU and thus had an orbital period of about 21 million years (uncertainty ± 25%). After a hypothetical departure from the solar system, the semi-major axis of its orbit would most likely have been reduced to about 6,000 AU and its orbital period to about 470,000 years. As before, these details are also very imprecise, so that the orbit time could also have been significantly shorter or the path could also have become slightly hyperbolic.
See also
Web links
- C / 2009 R1 (McNaught) Seiichi Yoshida's Home Page (English)
Individual evidence
- ^ GW Kronk: C / 2009 R1 (McNaught). In: Gary W. Kronk's Cometography. Retrieved July 20, 2020 .
- ↑ a b C / 2009 R1 McNaught. Solar System Dynamics & Planetology Group, 2013, accessed July 20, 2020 .
- ↑ P. Korsun, I. Kulyk, S. Velichko: The spectrum of comet C / 2009 R1 (McNaught) in 4140-5240 Å wavelength region. In: Planetary and Space Science. Volume 60, No. 1, 2012, pp. 255-260 doi: 10.1016 / j.pss.2011.08.016 .
- ↑ LN Volvach, AA Berezhnoi, AE Volvach: Observation of comets C / 2009 R1 (McNaught) and 17P / Holmes in the OH line at a wavelength of 18 cm. In: Bulletin of the Crimean Astrophysical Observatory. Volume 109, 2013, pp. 71-75 doi: 10.3103 / S0190271713010270 .
- ↑ C / 2009 R1 (McNaught) in the Small-Body Database of the Jet Propulsion Laboratory (English).
- ↑ A. Vitagliano: SOLEX 12.1. Retrieved July 9, 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 )