C/1999 T1 (McNaught–Hartley) is a near-parabolic long-period comet, discovered by Robert H. McNaught and Malcolm Hartley at the Siding Spring Observatory in 1999.[4]
| Discovery[1] | |
|---|---|
| Discovered by | Robert H. McNaught Malcolm Hartley |
| Discovery site | Siding Spring Observatory |
| Discovery date | 7 October 1999 |
| Designations | |
| Comet McNaught-Hartley | |
| Orbital characteristics[2][3] | |
| Epoch | 2 December 2000 (JD 2451880.5) |
| Observation arc | 787 days (2.15 years) |
| Number of observations | 661 |
| Aphelion | 16,247 AU |
| Perihelion | 1.172 AU |
| Semi-major axis | 8,124 AU |
| Eccentricity | 0.99985 |
| Orbital period | 732,246 years |
| Inclination | 79.975° |
| 182.483° | |
| Argument of periapsis | 344.758° |
| Last perihelion | 13 December 2000 |
| TJupiter | 0.234 |
| Earth MOID | 0.19397 AU |
| Jupiter MOID | 3.41621 AU |
| Physical characteristics | |
| 1–10 days | |
| Comet total magnitude (M1) | 8.3 |
Observations
Comet McNaught–Hartley was a magnitude 15 object upon discovery on October 7, 1999.[4] Gas emissions were measured in x-ray light by the Chandra observatory (alongside C/1999 S4 (LINEAR)) between 8–14 January 2001.[5][6] Observations of its coma between January 26 and February 5, 2001 show that the nucleus has a rotation period between 1 and 10 days.[7]
Encounter with the Ulysses probe
Research published in 2004 found that the Ulysses spacecraft had likely detected ions from the comet tail of C/1999 T1. This was the spacecraft's second encounter with a comet tail, after Comet Hyakutake in 1996.[8][9]
See also
References
External links
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