2015 YA

2015 YA
Discovery
Discovered by Catalina Sky Srvy.
Discovery site Mount Lemmon Obs.
Discovery date 16 December 2015
Designations
MPC designation 2015 YA
Aten · NEO[1][2]
Earth crosser
Orbital characteristics[2][3][4]
Epoch January 13, 2016 (JD 2457400.5)
Uncertainty parameter 6
Observation arc 5 days
Aphelion 1.27598 AU
Perihelion 0.71908 AU
0.99753 AU
Eccentricity 0.2791
0.99632 y (363.91 d)
99.79°
Inclination 1.6249°
255.3291°
83.849°
Earth MOID 0.00356 AU
Physical characteristics
Dimensions 9–22 m[a][5]
27.4[2]

    2015 YA is a sub-kilometer asteroid, classified as near-Earth object of the Aten group, that is a temporary horseshoe companion to the Earth. It is the 11th known Earth horseshoe librator.[6] Prior to a close encounter with the Earth on 15 December 2015, 2015 YA was an Apollo asteroid.

    Discovery

    2015 YA was discovered on 2015 December 16 G. J. Leonard and R. G. Matheny observing for the Catalina Sky Survey.[7] As of 9 March 2016, it has been observed 47 times with an observation arc of 5 days.[2]

    Orbit and orbital evolution

    2015 YA is currently an Aten asteroid (Earth-crossing but with a period less than a year). Its semi-major axis (currently 0.99753 AU) is similar to that of Earth (1.00074 AU), but it has a moderate eccentricity (0.2791) and very low orbital inclination (1.6249°). It alternates between being an Aten asteroid and being an Apollo asteroid, although its orbital evolution is rather chaotic. As of 9 March 2016, this object is the 16th known Earth co-orbital and the 11th known object following a horseshoe path with respect to our planet. Asteroid 2015 YA follows an asymmetrical horseshoe path with respect to our planet; the value of its relative mean longitude oscillates about 180°, but enclosing 0°.[6]

    Physical properties

    With an absolute magnitude of 27.4 mag, it has a diameter in the range 9–22 meters (for an assumed albedo range of 0.04–0.20, respectively).

    See also

    Notes

    • ^ This is assuming an albedo of 0.20–0.04.

    References

    1. ↑ List Of Aten Minor Planets
    2. 1 2 3 4 2015 YA at the JPL Small-Body Database
    3. ↑ AstDys-2 on 2015 YA Retrieved 2016-03-09
    4. ↑ NEODyS-2 on 2015 YA Retrieved 2016-03-09
    5. ↑ Absolute-magnitude conversion table (H)
    6. 1 2 de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (1 April 2016). "A trio of horseshoes: past, present and future dynamical evolution of Earth co-orbital asteroids 2015 XX169, 2015 YA and 2015 YQ1". Astrophysics and Space Science. 361 (4): 121 (13 pages). arXiv:1603.02415. Bibcode:2016Ap&SS.361..121D. doi:10.1007/s10509-016-2711-6.
    7. ↑ Discovery MPEC
    Further reading

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