C/2010 U3 (Boattini) is the hyperbolic comet with the longest observation arc[4] and took around a million years to complete half an orbit from its furthest distance in the Oort cloud. It was discovered on 31 October 2010 by Andrea Boattini in images taken with the Mount Lemmon Survey's 1.5-m reflector. The perihelion point is outside of the inner Solar System.[2]
| Discovery | |
|---|---|
| Discovered by | Andrea Boattini Mount Lemmon Survey 1.5-m reflector |
| Discovery date | 31 October 2010 |
| Orbital characteristics | |
| Epoch | 2017-Jun-01 (JD 2457905.5) |
| Observation arc | 16.6 years |
| Number of observations | 4351 |
| Orbit type | Oort cloud |
| Aphelion | ~34,000 AU (inbound)[1] ~9,900 AU (outbound) |
| Perihelion | 8.4458 AU[2] (q) (outside of Jupiter's orbit) |
| Eccentricity | 0.99950 (inbound)[1] 1.0009 (near perihelion)[2] 0.982 (outbound)[1] |
| Orbital period | ~2.2 million yr (inbound)[1][3] ~350,000 yr (outbound) |
| Inclination | 55.512°[2] |
| Last perihelion | 26 February 2019[2] |
| Jupiter MOID | 6.33 AU |
The comet has an observation arc of 15 years[2] allowing a very good estimate of the inbound (original) and outbound (future) orbits. The orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the Solar System. Inbound JPL Horizons shows an epoch 1950 barycentric orbital period of 2.2 millions years with aphelion of 34,000 AU (0.5 ly) from the Sun.[1] Hui et al 2019 has a similar inbound orbital period of 2 million years.[3] Outbound with an epoch of 2050 JPL Horizons shows a period of approximately 350,000 years and an aphelion distance of 9,900 AU (0.2 ly).[1]
The generic JPL Small-Body Database browser uses a near-perihelion epoch of 2017-Jun-01[2] which is before the comet left the planetary region and makes the highly eccentric aphelion point inaccurate since it does not account for any planetary perturbations after that epoch. The heliocentric JPL Small-Body Database solution also does not account for the combined mass of the Sun+Jupiter.
Precovery images from November 2005 when the comet was active 25.8 AU (3.86 billion km) from the Sun are known.[3] The comet was seen to outburst in 2009 and 2017. The coma and tail consist of dust grains about 20 μm in diameter ejected at less than 50 meters per second (110 miles per hour). Supervolatiles such as CO and CO2 can generate activity when a comet is this far from the Sun.
References
edit- ^ a b c d e f Horizons output. "Barycentric Osculating Orbital Elements for Comet C/2010 U3 (Boattini)". Solution using the Solar System Barycenter. Ephemeris Type:Elements and Center:@0 (To be outside planetary region, inbound epoch 1950 and outbound epoch 2050. For epoch 1950-Jan-01 orbit period is "PR= 8E+08 / 365.25 days" = ~2.2 million years)
- ^ a b c d e f g "JPL Small-Body Database Browser: C/2010 U3 (Boattini)" (last observation: 2021-07-02; arc: 15.6 years). Jet Propulsion Laboratory. Retrieved 2021-06-20.
- ^ a b c Hui, Man-To; Farnocchia, Davide; Micheli, Marco (2019). "C/2010 U3 (Boattini): A Bizarre Comet Active at Record Heliocentric Distance". The Astronomical Journal. 157 (4): 162. arXiv:1903.02260. Bibcode:2019AJ....157..162H. doi:10.3847/1538-3881/ab0e09.
- ^ "JPL Small-Body Database Search Engine: e > 1 (sorted by obs arc)". JPL Solar System Dynamics. Retrieved 2021-06-20.