2015 YQ1

2015 YQ₁

Discovery
Discovered by	Mount Lemmon Srvy.
Discovery site	Mount Lemmon Obs.
Discovery date	19 December 2015
Designations
Designation	2015 YQ1
Minor planet category	Apollo asteroid Earth crosser
Orbital characteristics
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 6
Observation arc	3 days
Aphelion	1.40586 AU
Perihelion	0.59681 AU
Semi-major axis	1.00134 AU
Eccentricity	0.40398
Orbital period (sidereal)	1.00202 y (365.99 d)
Mean anomaly	317.067°
Inclination	2.4865°
Longitude of ascending node	88.89770°
Argument of perihelion	112.185°
Earth MOID	0.00052 AU
Physical characteristics
Dimensions	7–16 m[a]
Absolute magnitude (H)	28.1

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. It experienced a close encounter with the Earth on 2015 December 22 at 0.0037 AU.

Discovery

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. As of 9 March 2016, it has been observed 64 times with an observation arc of 3 days.

Orbit and orbital evolution

Animation of 2015 YQ1's orbit relative to Sun and Earth
  2015 YQ1 ·   Sun ·   Earth

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.

Physical properties

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).

See also

• 54509 YORP
• (419624) 2010 SO16
• 3753 Cruithne
• 2015 SO2
• 2015 XX169
• 2015 YA

Notes

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

References

Further reading

• Understanding the Distribution of Near-Earth Asteroids Bottke, W. F., Jedicke, R., Morbidelli, A., Petit, J.-M., Gladman, B. 2000, Science, Vol. 288, Issue 5474, pp. 2190–2194.
• A Numerical Survey of Transient Co-orbitals of the Terrestrial Planets Christou, A. A. 2000, Icarus, Vol. 144, Issue 1, pp. 1–20.
• Debiased Orbital and Absolute Magnitude Distribution of the Near-Earth Objects Bottke, W. F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H. F., Michel, P., Metcalfe, T. S. 2002, Icarus, Vol. 156, Issue 2, pp. 399–433.
• Transient co-orbital asteroids Brasser, R., Innanen, K. A., Connors, M., Veillet, C., Wiegert, P., Mikkola, S., Chodas, P. W. 2004, Icarus, Vol. 171, Issue 1, pp. 102–109.
• A trio of horseshoes: past, present and future dynamical evolution of Earth co-orbital asteroids 2015 XX₁₆₉, 2015 YA and 2015 YQ₁ de la Fuente Marcos, C., de la Fuente Marcos, R. 2016, Astrophysics and Space Science, Vol. 361, Issue 4, article 121 (13 pp).

External links

• MPEC 2015-Y53 : 2015 YQ1, Discovery Minor Planet Electronic Circular, (at ADS)
• 2015 YQ₁ data at MPC
• 2015 YQ1 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 2015 YQ1 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 2015 YQ1 at the JPL Small-Body Database