C/2015 ER61 (PANSTARRS)

2015 ER61 (PANSTARRS)
Discovery
Discovered by Pan-STARRS 1 (F51)
Discovery date 15 March 2015
Designations
Amor, NEO, damocloid, scattered disc object, centaur
Orbital characteristics
Epoch 2015-Jun-27 (JD 2457200.5)
Observation arc 1 yr
Aphelion 2456 ± 62 AU
1425/854 AU
Perihelion 1.059306 ± 0.000046 AU
1229 ± 31 AU
715/428 AU
Eccentricity 0.999138 ± 0.000022
43060 ± 1620 years (1.6x10^7 ± 5.9x10^5 days
359.98435 ± 0.00059°
Inclination 6.129721 ± 0.000071°
238.8124 ± 0.0022°
64.0806 ± 0.0020°
Earth MOID 0.1035 AU
Mars MOID less than 0.01 AU
Jupiter MOID 0.0287 AU
Physical characteristics
Dimensions 9–22 km[1]
20 km
Albedo ~0.05 (assumed)
20.5 (Jan 2016)
14.74 (peak 1 May 2017)
12.2

    2015 ER61 is a comet, centaur, inner Oort cloud object, Amor near-Earth asteroid, and possibly a damocloid. It has the fourth-largest aphelion of any known minor planet in the Solar System, after 2005 VX3, 2012 DR30, and 2013 BL76. It additionally has the most eccentric orbit of any known minor planet, with its distance from the Sun varying by about 99.9% during the course of its orbit, followed by 2005 VX3 with an eccentricity of 0.9973. On January 30, 2016, it was classified as a comet when it was 5.7 AU from the Sun.[2]

    It comes close to Jupiter, and a close approach in the past threw it on the distant orbit it is on now. It also has a small MOID to Mars of less 0.01 AU

    2017 Perihelion

    2015 ER61 was discovered on March 15, 2015 when it was 8.44 AU from the Sun, and magnitude 21.5. As of September 2015, it is magnitude 21.2, and slowly increasing in brightness. In early February 2016, the object reached magnitude 20, and will make a close approach to Jupiter on March 28, 2016 of 0.9245 AU.[3] This will change its orbit, significantly decreasing its aphelion distance from 1430 AU to ~1200 AU, and as it passes through the inner Solar System its aphelion decreases to 160 AU, and by 2020 will have an aphelion of 854 AU.

    On April 4, 2017, 2015 ER61 will reach its closest point to the Earth, at ~1.42 AU. At this point, it will be magnitude 14.8, and, assuming a size of 20 km, have an apparent size of 19 mas. It will not be 50 AU from the Sun until 2045.

    Orbital elements table

    Distance
    from
    Sun    		 Event Epoch Aphelion
    (Q)    		 Perihelion
    (q)    		 Semi-major axis
    (a)    		 Eccentricity
    (e)    		 Period
    (p)    		 Inclination
    (i)    		 Longitude ascending node
    (Ω)    		 Mean anomaly
    (M)    		 Argument of perihelion
    (ω)
    AU (years) (°)
    36.5 AU 2000/01/01 1423.4 1.05378 712.2 0.99852 18,990 6.12745 239.06 359.671 63.99
    20.2 AU 2010/01/01 1435.4 1.05377 718.2 0.99853 19,240 6.12732 239.03 359.862 64.01
    9.01 AU 2015/01/01 1430.8 1.05347 715.9 0.99853 19,140 6.12819 238.97 359.956 64.08
    8.44 AU discovery 2015/03/15 1436.1 1.05313 718.6 0.99853 19,250 6.12879 238.95 359.960 64.11
    6.008 AU 2016/01/01 1667.3 1.04763 834.2 0.99874 24,080 6.15827 238.25 359.980 64.92
    5.204 AU Jupiter approach 2016/03/28 1291.9 1.04030 646.5 0.99839 16,420 6.24250 236.73 359.976 66.64
    2.242 AU 2017/01/01 324.6 1.03505 162.8 0.99364 2,080 6.34928 235.27 359.939 68.46
    1.079 AU Earth approach 2017/04/04 164.3 1.03830 82.7 0.98744 750 6.34595 235.27 359.953 68.30
    1.0397 AU Perihelion 2017/05/10 210.0 1.03973 105.5 0.99015 1,080 6.34423 235.25 000.0004 67.92
    3.437 AU 2018/01/01 1091.1 1.04449 546.1 0.99809 12,750 6.34438 235.23 000.018 68.27
    9.78 AU 2020/01/01 857.8 1.04583 429.4 0.99756 8,890 6.34009 235.21 000.107 68.29
    56.03 AU 2050/01/01 854.6 1.04649 427.8 0.99755 8,840 6.33543 235.18 001.329 68.34

    Comparison

    Sedna compared to some other very distant orbiting bodies. Including 90377 Sedna, 2015 DB216 (orbit wrong), 2000 OO67, 2004 VN112, 2005 VX3, 2006 SQ372, 2007 TG422, 2007 DA61, 2009 MS9, 2010 GB174, 2010 NV1, 2010 BK118, 2012 DR30, 2012 VP113, 2013 BL76, 2013 AZ60, 2013 RF98, 2015 ER61

    See also

    Notes

    ^ assuming a comet-like albedo of 0.05

    ^ ^ Because 2015 ER61's orbit takes it so far from the Sun, a more accurate value for its orbit is a barycentric solution. Additionally, a close approach to Jupiter in 2016, and a travel through the inner solar system in 2017 drastically changes its orbit. Therefore, orbits for 2000-2016 and 2018-2100 are provided, respectively.

    References

    1. ↑ "Glossary: Absolute Magnitude (H)". JPL. NASA. Retrieved 14 September 2015.
    2. ↑ "MPEC 2016-C01 : COMET C/2015 ER61 (PANSTARRS)". IAU Minor Planet Center. 2016-02-01. Retrieved 2016-02-01. (CK15E61R)
    3. ↑ "JPL Small-Body Database Browser: (2015 ER61)" (last observation: 2016-01-23; arc: 1 yr). Jet Propulsion Laboratory.

    External links

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