Discovery | |
---|---|
Discovered by | Mount Lemmon Srvy. |
Discovery site | Mount Lemmon Obs. |
Discovery date | 19 December 2015 |
Designations | |
Designation | 2015 YQ1 |
Orbital characteristics [2] [3] [4] | |
Epoch 13 January 2016 ( JD 2457400.5) | |
Uncertainty parameter 6 | |
Observation arc | 3 days |
Aphelion | 1.40586 AU |
Perihelion | 0.59681 AU |
1.00134 AU | |
Eccentricity | 0.40398 |
1.00202 y (365.99 d) | |
317.067° | |
Inclination | 2.4865 ° |
88.89770° | |
112.185° | |
Earth MOID | 0.00052 AU |
Physical characteristics | |
Dimensions | 7–16 m [a] [5] |
28.1 [2] | |
2015 YQ1 (also written 2015 YQ1) is an Apollo asteroid that is a temporary horseshoe companion to the Earth, the twelfth known Earth horseshoe librator. [6] It experienced a close encounter with the Earth on 2015 December 22 at 0.0037 AU.
2015 YQ1 was discovered on 2015 December 19 by A. D. Grauer observing with the 1.5-m reflector telescope at the Mount Lemmon Survey. [7] As of 9 March 2016, it has been observed 64 times with an observation arc of 3 days. [2]
2015 YQ1 is currently an Apollo asteroid (Earth-crossing but with a period greater than a year). Its semi-major axis (currently 1.00134 AU) is similar to that of Earth (1.00074 AU), but it has a relatively high eccentricity (0.40398) and low orbital inclination (2.4865°). It alternates between being an Aten asteroid and being an Apollo asteroid. As of 9 March 2016, this object is the 17th known Earth co-orbital and the 12th known object following a horseshoe path with respect to our planet. Asteroid 2015 YQ1 follows an asymmetrical horseshoe path with respect to our planet; the value of its relative mean longitude oscillates about 180°, but enclosing 0°; its orbital evolution is rather unstable. [6]
With an absolute magnitude of 28.1 mag, it has a diameter in the range 7–16 meters (for an assumed albedo range of 0.04–0.20, respectively).