2018 CY₂

The orbit of 2018 CY2 before and after flyby on 14 February 2018
Discovery [1][2]
Discovered by	CSS
Discovery site	Mount Lemmon Obs.
Discovery date	9 February 2018 (first observed only)
Designations
MPC designation	2018 CY2
Minor planet category	NEO · Apollo [3][1]
Orbital characteristics [3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 7
Observation arc	5 days
Aphelion	1.3360 AU
Perihelion	0.9211 AU
Semi-major axis	1.1285 AU
Eccentricity	0.1838
Orbital period (sidereal)	1.20 yr (438 days)
Mean anomaly	338.04°
Mean motion	0° 49m 19.56s / day
Inclination	26.503°
Longitude of ascending node	144.03°
Argument of perihelion	73.482°
Earth MOID	0.0451 AU · 17.6 LD
Physical characteristics
Mean diameter	59–190 m[4] 100 m (est. at 0.20)[5] 190 m (est. at 0.057)[5]
Absolute magnitude (H)	22.33[3]

2018 CY₂ is an asteroid, classified as a near-Earth object of the Apollo group, with an estimated diameter of 59–190 metres (190–620 ft). It was first observed on 9 February 2018, by astronomers of the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, during its close approach to Earth.^[1][2]

2018 CY₂ is an Apollo asteroid. Apollo's cross the orbit of Earth and are the largest group of near-Earth objects with nearly 10 thousand known members. It orbits the Sun at a distance of 0.92–1.34 AU once every 14 months (438 days; semi-major axis of 1.13 AU). Its orbit has an eccentricity of 0.18 and an inclination of 27° with respect to the ecliptic.^[3] It is, however, not a Mars-crossing asteroid, as its aphelion of 1.34 AU is less than the orbit of the Red Planet at 1.666 AU.^[3] The body's observation arc begins its first observation at Mount Lemmon in February 2018.^[1]

The object has a minimum orbital intersection distance with Earth of 6,750,000 km (0.0451 AU), which corresponds to 17.6 lunar distances (LD).^[3] On 14 February 2018, 14:44 UTC, it came within 18.66 LD of the Earth (see diagrams).^[4] Its next close approach will be on 14 February 2024, at a similar distance.^[3]

2018 flyby: Path in sky with daily motion north to south (left). View of path across Earth–Moon system, moving from north to south (right).

The Minor Planet Center estimates a diameter of 59–190 meters.^[4] Based on a generic magnitude-to-diameter conversion, 2018 CY₂ measures between 100 and 190 meters in diameter, for an absolute magnitude of 22.33, and an assumed albedo between 0.057 and 0.20, which represent typical values for carbonaceous and stony asteroids, respectively.^[5]

As of 2018, no rotational lightcurve of 2018 CY₂ has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.^[3]

This minor planet has neither been numbered nor named.^[1]

• List of asteroid close approaches to Earth in 2018

Wikimedia Commons has media related to 2018 CY2.

• MPEC 2018-C87 : 2018 CY2, Minor Planet Electronic Circular
• 2018 CY2 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 2018 CY2 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters