(15810) 1994 JR1

(15810) 1994 JR1

A distant view of 1994 JR1 from New Horizons in November 2015.[lower-alpha 1]
Discovery
Discovered by M. J. Irwin, A. Zytkow
Discovery date May 12, 1994
Designations
MPC designation (15810) 1994 JR1
Plutino[1][2]
Orbital characteristics[3]
Epoch April 18, 2013 (JD 2456400.5)
Aphelion 43.6977721 AU
Perihelion 34.7394915 AU
39.2186318 AU
Eccentricity 0.1142095
245.61 y (89709.1181843 d)
25.57449°
Inclination 3.80462 °
144.72980°
101.66735°
Physical characteristics
Dimensions 127 km[4]
Albedo 0.09 (assumed)
7.7[3]

    (15810) 1994 JR1, also written (15810) 1994 JR1, is a minor planet that orbits around the Sun in an orbit entirely located beyond Neptune. It is the first object that was confirmed to be a quasi-satellite of Pluto.[5]

    Discovery, orbit and physical properties

    (15810) 1994 JR1 was discovered on May 12, 1994, by M. J. Irwin and A. Zytkow with the 2.5 m Isaac Newton Telescope at the Roque de los Muchachos Observatory in the island of La Palma.[3] It is a plutino, so it is trapped in a 2:3 mean motion resonance with Neptune, similarly to dwarf planet Pluto (the largest known plutino). It has a perihelion (closest approach to the Sun) of 34.753 AU and an aphelion (farthest distance from the Sun) of 43.722 AU, so it is moving in a relatively eccentric orbit entirely beyond Neptune. It is about 127 km in diameter.[4]

    Quasi-satellite dynamical state and orbital evolution

    (15810) 1994 JR1 is currently following a quasi-satellite loop around Pluto.[5] In contrast with the cases of 2002 VE68 or (309239) 2007 RW10, the quasi-satellite state of (15810) 1994 JR1 is mainly the result of resonances with Neptune not caused by a discrete close encounter with another body. This dynamical behavior is recurrent: the object becomes a Plutonian quasi-satellite every 2 Myr and remains in that phase for nearly 350,000 years.[5][6]

    Origin

    (15810) 1994 JR1 is moving in a very stable orbit, likely as stable as Pluto's. This suggests that it may be a primordial plutino formed around the same time Pluto itself and Charon came into existence. It is unlikely to be relatively recent debris originated in collisions within Pluto’s system or a captured object.[5]

    New Horizons

    Orbit of 1994 JR1 near Pluto

    (15810) 1994 JR1 is currently a relatively close neighbor of Pluto's. In 2017, it will be only 2.7 AU from Pluto.[7] Before 2014 MU69 was discovered in 2014, (15810) 1994 JR1 was the best known target for a flyby by the New Horizons spacecraft after its Pluto flyby in 2015.[8][9]

    1994 JR1 was one of the first objects targeted for distant observations by New Horizons, which were taken on November 2, 2015.[10]

    On 2 November 2015, 1994 JR1 was imaged by the LORRI instrument aboard New Horizons, making the closest observation of a Kuiper Belt object by a factor of 15 of anything outside the Pluto-Charon system.[11]

    References

    Notes
    1. ↑ This four-frame animation depicting 1994 JR1 was taken on November 2, 2015 by New Horizons, when the spacecraft was 270 million kilometers (170 million miles) away. 1994 JR1 is the white dot, just left of center, moving from right to left.
    Citations
    1. ↑ Marc W. Buie (2006-10-14). "Orbit Fit and Astrometric record for 15810". SwRI (Space Science Department). Retrieved 2008-10-02.
    2. ↑ Brian G. Marsden (2008-07-17). "MPEC 2008-O05 : Distant Minor Planets (2008 Aug. 2.0 TT)". IAU Minor Planet Center. Harvard-Smithsonian Center for Astrophysics. Archived from the original on 7 December 2008. Retrieved 2008-10-02.
    3. 1 2 3 "JPL Small-Body Database Browser: 15810 (1994 JR1)" (2000-06-25 last obs). Retrieved 2008-10-02.
    4. 1 2 "List of Known Trans-Neptunian Objects". Johnston's Archive. Archived from the original on 18 February 2007. Retrieved 2007-01-25.
    5. 1 2 3 4 de la Fuente Marcos, C.; de la Fuente Marcos, R. (November 2012). "Plutino 15810 (1994 JR1), an accidental quasi-satellite of Pluto". Monthly Notices of the Royal Astronomical Society: Letters 427 (1): L85–L89. arXiv:1209.3116. Bibcode:2012MNRAS.427L..85D. doi:10.1111/j.1745-3933.2012.01350.x.
    6. ↑ "Pluto's fake moon". Archived from the original on 2015-03-25. Retrieved 2012-09-24.
    7. ↑ "50000 Quaoar distance (AU) from Pluto". Retrieved 2007-12-18.
    8. ↑ Ted Stryk / Emily Lakdawalla (January 24, 2011). "Ted Stryk: Report from the 2011 New Horizons Science Team Meeting". The Planetary Society Blog. Retrieved 2011-01-25.
    9. ↑ "25 closer candidates". Retrieved 2012-09-30.
    10. ↑ "A Distant Close-up: New Horizons’ Camera Captures a Wandering Kuiper Belt Object". New Horizons. NASA/JHUAPL. December 4, 2015. Retrieved December 5, 2015.
    11. ↑ "New Horizons' catches a wandering Kuiper Belt Object not far off". SpaceDaily. 7 December 2015.

    External links

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