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2016 WF9

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2016 WF9
Artist's rendition of2016 WF9
Discovery[1]
Discovered byNEOWISE
Discovery siteEarth orbit
Discovery date27 November 2016
(discovery: first observed)
Designations
2016 WF9
NEO·PHA·Apollo[2][3]
Orbital characteristics[2]
Epoch4 September 2017 (JD2458000.5)
Uncertainty parameter4
Observation arc(192 days)
Aphelion4.7614AU
Perihelion0.9816 AU
2.8715 AU
Eccentricity0.6582
4.87yr(1,777 days)
43.511°
0° 12m9.36s/ day
Inclination14.995°
125.41°
342.45°
EarthMOID0.0156 AU (6.1LD)
JupiterMOID0.5211 AU
TJupiter2.893(comet-like)
Physical characteristics
0.5–1.0 km[4]
<0.05(dark)
20.2[2]

2016 WF9is a dark, sub-kilometerasteroidand suspectedextinct comet,classified asnear-Earth objectandpotentially hazardous asteroidof theApollo group.[3]

Description

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2016 WF9is unusually dark for a near-Earth asteroid. It is possibly anextinct comet,but without thecomet-like dust and gas cloud.[4]It was first observed on 27 November 2016 byNEOWISE,the asteroid-and-comet-hunting portion of the Wide-Field Infrared Survey Explorer (WISE) mission.[4]According to NEOWISE, this object could havecometaryorigins, which illustrates the blurry boundary between asteroids and comets. It is speculated that over time, this object has lost the majority of thevolatileson its surface.[5]

2016 WF9is about 0.5–1.0 km (0.3–0.6 mi) across so is one of the largerpotentially hazardous asteroidnear-Earth object(also seelist of largest PHAs).[4]

2017 approach

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2016 WF9passedEarthon 25 February 2017 at a distance of 0.3407AU(50,970,000km;31,670,000mi) and is not considered a threat for the foreseeable future.[4][2]The 2017 approach did not bring it particularly close to Earth.[4]In December 1944 it passed about 0.19 AU (28,000,000 km; 18,000,000 mi) from Earth and in February 2149 it will pass about 0.06 AU (9,000,000 km; 5,600,000 mi) from Earth.[2]

Discovery

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When2016 WF9was first announced and had a short insignificant 3 dayobservation arc,it was estimated to have a 7.6 yearorbital period.[1]The preliminary orbit was also listed on the JPLSentry Risk Table,but none of the virtual impact dates were before 2029.[6]As the observation arc became longer and the orbital parameters better constrained, it was removed from the Sentry Risk Table on 20 December 2016.[7]With a 111-day observation arc, it is now known that it has a 4.86 year orbital period and currently stays inside the orbit ofJupiter.[2]

A simulation of2016 WF9's dynamics over a period of 100 million days (~274,000 years) found that it had roughly a 60% chance of originating from the outer Solar System as a long-period comet.[8]

Orbit of2016 WF9on 25 February 2017, closest approach to Earth.[2]

References

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  1. ^ab"MPEC 2016-W125: 2016 WF9".IAU Minor Planet Center.30 November 2016.Retrieved2 February2017.(K16W09F)
  2. ^abcdefg"JPL Small-Body Database Browser: (2016 WF9)"(2017-04-20 last obs.).Jet Propulsion Laboratory.Retrieved8 February2018.
  3. ^ab"2016 WF9".Minor Planet Center.Retrieved8 February2018.
  4. ^abcdefAgle, DC; Cantillo, Laurie; Brown, Dwayne (29 December 2016)."NASA's NEOWISE Mission Spies One Comet, Maybe Two".NASA.Retrieved29 December2016.
  5. ^Williams, Matt (30 December 2016)."NASA'S NEOWISE Missions Spots New Comets".Universe Today.Retrieved31 December2016.
  6. ^"Tracking News".hohmanntransfer. 1 December 2016. Archived fromthe originalon 3 February 2017.Retrieved2 February2017.
  7. ^"Date/Time Removed".NASA/JPL Near-Earth Object Program Office. Archived fromthe originalon 2 June 2002.Retrieved2 February2017.
  8. ^Odasso, Alessandro (9 January 2017)."2016 WF9 – a simulation based on Jan 5th orbital params".odassoastro.blogspot.it.Retrieved9 January2017.
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