 | |
| Discovery[2][3] | |
|---|---|
| Discovered by | Donna M. Burton |
| Discovery site | Siding Spring, Australia 0.5-mSchmidt (E12) |
| Discovery date | 25 August 2007 |
| Orbital characteristics[4][5] | |
| Epoch | 20 August 2009 (JD 2455063.5) |
| Observation arc | 4.02 years (1,470 days) |
| Number of observations | 1,333 |
| Orbit type | Oort cloud |
| Aphelion | ~69,000 AU (inbound) ~15,000 AU (outbound) |
| Perihelion | 2.252 AU |
| Semi-major axis | ~7,500 AU (outbound) |
| Eccentricity | 1.0002077 |
| Orbital period | 6.4 million years (inbound) ~650,000 years (outbound) |
| Inclination | 65.650° |
| 149.41° | |
| Argument of periapsis | 2.093° |
| Last perihelion | 7 October 2009 |
| TJupiter | 0.767 |
| EarthMOID | 1.262 AU |
| JupiterMOID | 3.129 AU |
| Physical characteristics[5][6] | |
| Comet total magnitude (M1) | 8.6 |
| 8.7 (2009 apparition) | |
C/2007 Q3 (Siding Spring), is anOort cloudcomet that was discovered by Donna Burton in 2007 atSiding Spring Observatory inNew South Wales, Australia.[7] Siding Spring came within 1.2 AU (180 million km) of Earth and 2.25 AU (337 million km) of the Sun on October 7, 2009.[1] The comet was visible with binoculars until January 2010.[7]
Images of the comet taken in March 2010 by N. Howes using the Faulkes telescope, showed that thenucleus hadfragmented.[8]
The comet has an observationarc of 1,333 days and was continuously observed until September 2011.[5] The orbit of a long-period comet is properly obtained when theosculating orbit is computed at anepoch after leaving the planetary region and is calculated with respect to thecenter of mass of the Solar System. UsingJPL Horizons, the barycentric orbital elements for epoch 2030-Jan-01 generate asemi-major axis of 7,500 AU (0.119 ly), anapoapsis distance of 15,000 AU (0.24 ly), and a period of approximately 650,000 years.[4]
Before entering the planetary region (epoch 1950), C/2007 Q3 had a calculated barycentric orbital period of ~6.4 million years with an apoapsis (aphelion) distance of about 69,000 AU (1.09 ly).[4] The comet was probably in the outerOort cloud for millions or billions of years with a loosely bound chaotic orbit until it wasperturbed inward.[9]
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