| Discovery | |
|---|---|
| Discovered by | Catalina Sky Survey 1.5-m reflector (703)[1][2] |
| Discovery date | March 23, 1999 |
| Orbital characteristics | |
| Epoch | May 14, 2001 (JD 2452043.5) |
| Observation arc | 6.46 years |
| Number of observations | 166 |
| Orbit type | Oort cloud |
| Aphelion | ~54,000AU (inbound)[3] ~66,000 AU (outbound) |
| Perihelion | 5.787 AU[4] (q) (outside ofJupiter's orbit) |
| Eccentricity | 0.99914[4] |
| Orbital period | ~4 millionyr (inbound)[3] ~6 million yr (outbound) |
| Inclination | 92.035°[4] |
| Last perihelion | February 13, 2002[4] |
| JupiterMOID | 2.91 AU |
C/1999 F1 (Catalina) is one of the longest knownlong-period comets. It was discovered on March 23, 1999, by theCatalina Sky Survey.[1] The currentperihelion point is outside of theinner Solar System[4] which helps reduce planetaryperturbations to this outerOort cloud object and keep the inbound and outbound orbital periods similar.
The comet has anobservation arc of 6 years[4] allowing a good estimate of the inbound (original) and outbound (future) orbits. 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. C/1999 F1 made its closest approach toNeptune in August 2017.[5] UsingJPL Horizons, the barycentric orbital elements for epoch 2050-Jan-01 generate asemi-major axis of 33,000 AU, anaphelion distance of 66,000 AU (1 ly), and a period of approximately 6 million years.[3] The large distance of the comet from Sun mean that galactic and stellar gravitational perturbations can change its orbit. The comet will pass 11,000 AU (0.17 ly) fromGliese 710. Smaller perturbations may be caused by approaching 1.78 parsec from HD 179939.[6]
The genericJPL Small-Body Database browser uses a near-perihelion epoch of 2001-May-25[4] which is before the comet left the planetary region and makes the highly eccentric aphelion point inaccurate since it does not account for any planetaryperturbations after that epoch. The heliocentric JPL Small-Body Database solution also does not account for the combined mass of the Sun+Jupiter.
There was potential for a close approach to Saturn when C/1999 F1 crossed theecliptic plane in 1999, but Saturn was on the other side of its orbit.
| Planet | MOID (AU) | Actual Approach Distance (AU) | Date of Closest Approach |
|---|---|---|---|
| Jupiter | 2.914 | 7.68 | 2002-04-24 |
| Saturn | 0.159 | 10.1 | 2003-03-01 |
| Uranus | 2.944 | 7.70[7] | 2011-10-19 |
| Neptune | 10.11 | 22.1[5] | 2017-08-31 |
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