C / 2007 Q3 (Siding Spring)
| C / 2007 Q3 (Siding Spring) [i] | |
|---|---|
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| C / 2007 Q3 on 02/21/2010 | |
| Properties of the orbit ( animation ) | |
| Orbit type |
hyperbolic s. Cape. Orbit |
| Numerical eccentricity | 1,00024 |
| Perihelion | 2.252 AU |
| Inclination of the orbit plane | 65.7 ° |
| Perihelion | October 7, 2009 |
| Orbital velocity in the perihelion | 28.1 km / s |
| history | |
| Explorer | Donna Burton , Siding Spring Observatory |
| Date of discovery | August 25, 2007 |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 2007 Q3 (Siding Spring) is a comet that could only be observed with optical aids in Europe in 2009 and 2010.
Discovery and observation
The comet was discovered by D. Burton at the Siding Spring Observatory in New South Wales as part of the Siding Spring Survey . At the time of its discovery, the object was still over 7.6 AU from the Sun and could not be clearly identified as a comet. This was only possible after further recordings in the next few days, which is why the comet was not named after its discoverer.
When it was discovered in the southern sky , the comet had a magnitude of 18 mag. For more than two years it could only be observed from the southern hemisphere . From October 2009 the comet could then be found in the northern hemisphere at a brightness of about 9-10 mag at dawn . The comet continued to move north and could be observed from midnight by the end of the year. In the course of the first half of 2010 the brightness sank again to around 14 mag, but the comet could still be observed until September 2011.
On March 13, 2010, a photograph showed that a larger fragment had detached from the main body of the comet together with a smaller fragment. Further recordings on the following days were also able to confirm the larger fragment B, it was about 40 times weaker than the main component A. By April 12, no traces of the fragment could be found, apparently it had dissolved.
Scientific evaluation
With the ARC Échelle spectrometer at the Apache Point Observatory in New Mexico , a “forbidden” spectral line of oxygen in the light of the comet was observed at a distance of about 3 AU from the sun and production rates of carbon dioxide and water at this distance from the sun were derived from this.
As part of the commissioning of the WISE space telescope in January 2010, a number of images were taken, including an infrared image of comet C / 2007 Q3 (Siding Spring).
Orbit
A temporary hyperbolic orbit could be determined for the comet from 1335 observation data over a period of four years , which is inclined by around 66 ° 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 October 7, 2009, it was still about 2.25 AU / 336.9 million km from the Sun and was thus in the asteroid belt between the orbits of Mars and Jupiter . It did not come very close to any of the inner planets, the closest approach to Venus took place on October 15, 2009 to about 229.8 million km, to Mars on December 24, 2009 to about 302.7 million km, and to earth on February 2, 2010 to about 2.2 AU / 328.1 million km.
According to the orbital elements afflicted with a certain uncertainty, as they are specified in the JPL Small-Body Database and which do not take into account non-gravitational forces on the comet, its orbit would have had an elliptical characteristic with an eccentricity before it approached the inner solar system of about 0.99994 and a semi-major axis of about 36,000 AU, so that its orbital period would have been about 7 million years. Due to the gravitational pull of the planets, especially by passing the large planet Jupiter on June 6th, 2009 at a distance of about 7 ¼ AU, Saturn on November 13, 2009 in about 7 ½ AU distance, and one more time at Jupiter, namely on the 7th May 2010 at a distance of about 7 AU, its orbital eccentricity would be reduced to about 0.99970 and its semi-major axis to about 7600 AU, so that the period of revolution would be about 660,000 years.
In a study from 2013, however, Królikowska and Dybczyński were able to show, using a total of 1368 observations of the comet over a period of more than four years, that this comet should be treated in a special way. They obtained the best agreement with the observed positions of the comet through a purely gravitational orbit determination and through a separate evaluation of the observation results before and after the perihelion passage. They initially used 568 observations to determine a set of orbit elements to describe the comet's orbit up to perihelion. Since a few months after the comet's perihelion passage could be observed how a larger fragment detached from it, which also affected the orbit of the main body, they did not consider the observations during this period, but used to determine a set of orbital elements to describe the Comet's orbit after perihelion only 177 observations from June 2010 onwards. In addition, they determined values for the original and future orbital shape long before and after passing through the inner solar system. As a result, they obtained that the comet, before approaching the Sun, was on an elliptical orbit with an eccentricity of about 0.99991, a semiaxial major axis of about 23,900 AU (uncertainty ± 1.3%) and an orbital time of about 3, 7 million years ago. For the future orbit, they determined an elliptical characteristic with an eccentricity of around 0.99970, a semi-major axis of around 7600 AU (uncertainty ± 2.8%) and an orbital period of around 660,000 years.
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 aforementioned numerical values could also be approximately confirmed here. They also classified the comet as "dynamically old", which means that it had already come close to the sun at least once. In doing so, it had probably approached the Sun up to a distance of about 9.6 AU.
See also
Web links
- C / 2007 Q3 (Siding Spring) Seiichi Yoshida's Home Page (English)
Individual evidence
- ^ A. Hale: 441. COMET SIDING SPRING C / 2007 Q3. In: Countdown to 500 Comets. Earthrise Institute, January 28, 2012, accessed July 26, 2020 .
- ↑ A. Kammerer: C / 2007 Q3 (Siding Spring). In: Expert group comets in the VdS. Vereinigung der Sternfreunde eV (VdS), accessed on July 26, 2020 .
- ↑ DWE Green: Comet C / 2007 Q3 (Siding Spring). In: IAU Circular, No. 9135 April 2020, accessed on July 26, 2020 .
- ↑ AJ McKay, NJ Chanover, JP Morgenthaler, AL Cochran, WM Harris, N. Dello Russo: Forbidden oxygen lines in Comets C / 2006 W3 Christensen and C / 2007 Q3 Siding Spring at large heliocentric distance: Implications for the sublimation of volatile ices . In: Icarus. Volume 220, No. 1, 2012, pp. 277-285 doi: 10.1016 / j.icarus.2012.04.030 .
- ↑ Multimedia Gallery - Comet Siding Spring. In: WISE Wide-field Infrared Survey Explorer. WISE at NASA / JPL, February 17, 2010, accessed July 26, 2020 .
- ↑ C / 2007 Q3 (Siding Spring) in the Small-Body Database of the Jet Propulsion Laboratory (English).
- ↑ A. Vitagliano: SOLEX 12.1. Retrieved July 9, 2020 .
- ↑ C / 2007 Q3 Siding Spring. Solar System Dynamics & Planetology Group, 2013, accessed July 25, 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 )