C/2018 F4 (PanSTARRS)
Perihelion 3.44584±0.0029 AU | | |
Eccentricity | 1.00385±0.0072[a] (JPL) 1.0130±0.0046 (MPC) | |
---|---|---|
Inclination | 78.2971±0.19° | |
Jupiter MOID | 0.60 AU (90 million km) | |
Physical characteristics | ||
Dimensions | 10–20 km (assumed)[3] | |
11.8±0.5 | ||
C/2018 F4 (PanSTARRS) is a
Overview
It would be no problem to fit a parabolic orbit to the C/2018 F4 data,[2][a] as used to be done for most short arc comets. The orbital eccentricity is decently constrained at 1.0038±0.0072,[a] so it could even be a closed orbit with an eccentricity below 1.[2] The velocity of the object currently has an uncertainty of ±0.2 km/s. With a common Oort cloud velocity of roughly 3 km/s (6,700 mph) when inbound 200 AU from the Sun, there is no reason to think 2018 F4 is of interstellar origin.[5]
It will come to perihelion around 3 December 2019 when it will be 3.4 AU from the Sun.[2]
Further observations will be necessary to determine if the orbit is hyperbolic. As a comet this object became known as C/2018 F4 (PANSTARRS).
The somewhat short
Object | Year | Velocity km/s |
# of observations and obs arc |
---|---|---|---|
90377 Sedna | 1746 | 1.99±0.00 | 196 in 9240 days |
C/1980 E1 (Bowell) | 1765 | 2.95±0.00 | 179 in 2514 days |
C/1997 P2 (Spacewatch) | 1779 | 2.96±0.01 | 94 in 49 days |
C/2010 X1 (Elenin) | 1798 | 2.96±0.00 | 2,222 in 235 days |
C/2012 S1 (ISON) |
1801 | 2.99±0.00 | 6,514 in 784 days |
C/2008 J4 (McNaught) | 1855 | 4.88±5.44 | 22 in 15 days |
C/2018 F4 | 1792 | 2.74±0.03 | 402 in 967 days |
C/1999 U2 (SOHO) | 1947 | 17±447 | 41 in 1 day |
1I/2017 U1 (ʻOumuamua) | 1982 | 26.49±0.03 | 121 in 34 days |
At 200 AU from the Sun, the escape velocity from the Sun is 2.98 km/s. In the above table, the only outlier is ʻOumuamua with a confident 34-day observation arc. Comet C/2008 J4 (McNaught) has a short observation arc with large uncertainties. Comet C/1999 U2 (SOHO) has a meaningless 1-day observation arc. Comet C/2018 F4 has a common Oort cloud velocity when 200 AU from the Sun.[5]
Notes
- ^ a b c C/2018 F4 could have an orbital eccentricity as low as 0.996. (Math: 1.0039-0.0072)
References
- ^ IAU Minor Planet Center. 2018-03-28. Retrieved 2018-03-28. (AK18F040)
- ^ a b c d e f "JPL Small-Body Database Browser: (A/2018 F4)" (2018-04-13 last obs.). Jet Propulsion Laboratory. Archived from the original on 28 March 2018. Retrieved 17 April 2018.
- ^ "Asteroid Size Estimator". Jet Propulsion Laboratory. Retrieved 28 March 2018.
- IAU Minor Planet Center. 2018-04-17. Retrieved 2018-04-17. (CK18F040)
- ^ S2CID 85517040.
- S2CID 209991168.
- ^ Re: fragmentation of comet C/2018 F4 (PANSTARRS)
- JPL. Results produced with JPL Horizons On-Line Ephemeris Systemusing Soln.date: 2018-Apr-29. Observer Location: "@sun"/ Table settings: "20. Observer range & range-rate", "39. Range & range-rate 3-sigmas". Columns: deldot, RNGRT_3sig