2011 CQ₁

2011 CQ₁ is a meteoroid discovered on 4 February 2011 by Richard A. Kowalski, at the Catalina Sky Survey.[1] On the same day the meteoroid passed within 0.85 Earth radii (5,480 kilometers (3,410 mi)) of Earth's surface, and was perturbed from the Apollo class to the Aten class of near-Earth objects.[5] With a relative velocity of only 9.7 km/s,[2] had the asteroid passed less than 0.5 Earth radii from Earth's surface, it would have fallen as a brilliant fireball. The meteoroid is between 80 centimeters (31 in) and 2.6 meters (100 in) wide.[5] The meteoroid was removed from the Sentry Risk Table on 5 February 2011.[6]

Parameter	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)
Units		AU				(days)	(°)
Pre-flyby	2011-Jan-26	1.347	0.9096	1.128	0.1940	437.9	1.073°	135.4°	310.9°	58.59°
Post-flyby	2011-Feb-08	1.009	0.6624	0.8360	0.2076	279.2	5.296°	315.4°	220.6°	335.1°

2011 CQ₁

Discovery[1]
Discovered by	Catalina Sky Survey Richard A. Kowalski
Discovery date	4 February 2011
Designations
MPC designation	2011 CQ1
Minor planet category	Aten NEO[2]
Orbital characteristics[2]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 5
Observation arc	12.4 hours[3] (35 observations used)
Aphelion	1.0087 AU (150.90 Gm) (Q)
Perihelion	0.66454 AU (99.414 Gm) (q)
Semi-major axis	0.83661 AU (125.155 Gm) (a)
Eccentricity	0.20567 (e)
Orbital period	0.77 yr (279.5 d)
Mean anomaly	18.607° (M)
Mean motion	1.2880°/day (n)
Inclination	5.2445° (i)
Longitude of ascending node	315.23° (Ω)
Argument of perihelion	335.40° (ω)
Earth MOID	0.000166307 AU (24,879.2 km)
Jupiter MOID	4.09715 AU (612.925 Gm)
Physical characteristics
Dimensions	~1 meter (39 in)
Apparent magnitude	14.2 (2011 peak)[4]
Absolute magnitude (H)	32.1[2]

It was not until 2020 QG on 16 August 2020 that a non-impacting closer approach to Earth was observed.

Animation of 2011 CQ1's orbit - 2011 flyby

Around the Sun

Around the Earth

   Sun ·   2011 CQ1 ·   Earth

See also

Closest non-impacting asteroids to Earth, except Earth-grazing fireballs

Asteroid	Date	Distance from surface of Earth	Uncertainty in approach distance	Reference
2020 VT4	2020-11-13	374 km	±25 km	data
2020 QG	2020-08-16	2946 km	±20 km	data
2011 CQ1	2011-02-04	5481 km	±5 km	data
2019 UN13	2019-10-31	6242 km	±200 km	data
2008 TS26	2008-10-09	6259 km	±1000 km	data
2004 FU162	2004-03-31	6542 km	±15000 km	data

References

1. "MPEC 2011-C12 : 2011 CQ1". IAU Minor Planet Center. 4 February 2011. Retrieved 27 February 2013. (K11C01Q)
2. "JPL Close-Approach Data: (2011 CQ1)" (last observation: 2011-02-04; arc: 1 day). Retrieved 31 March 2016.
3. "2011 CQ1". Minor Planet Center. Retrieved 21 August 2020.
4. "2011 CQ1 Ephemerides for 4 February 2011". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 28 February 2013.
5. Don Yeomans & Paul Chodas (4 February 2011). "Very Small Asteroid Makes Close Earth Approach on 4 February 2011". News. NASA/JPL Near-Earth Object Program Office. Archived from the original on 2 September 2011. Retrieved 18 September 2011.
6. "Date/Time Removed". NASA/JPL Near-Earth Object Program Office. Retrieved 19 March 2012.

External links

• Tiny Asteroid Zips Close By Earth space.com 6 February 2011
• Asteroid makes sharpest turn yet seen in solar system New Scientist 9 February 2011
• Asteroid's Record-Breaking Brush with Earth Changed It Forever Space.com 23 February 2011
• 2011 CQ1 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• 2011 CQ1 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical Properties · Summary
• 2011 CQ1 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters