2015 YA
Near-Earth horseshoe
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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 | |
|---|---|
| Discovered by | Catalina Sky Srvy. |
| Discovery site | Mount Lemmon Obs. |
| Discovery date | 16 December 2015 |
| Designations | |
Designation | 2015 YA |
| Orbital characteristics[2][3][4] | |
| Epoch 13 January 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] | |
Discovery
2015 YA was discovered on 16 December 2015 by 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 · Sun · Earth
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.