| Minorplanet: | yes |
| 2018 CB | |
| Background: |
|
| Discovered: | 4 February 2018 |
| Mpc Name: | 2018 CB |
| Mp Category: | NEOApollo |
| Epoch: | 23 March 2018 (JD 2458200.5) |
| Uncertainty: | 2 |
| Observation Arc: | 5 days |
| Perihelion: | 0.9582 AU |
| Semimajor: | 1.4085 AU |
| Eccentricity: | 0.3197 |
| Period: | 1.67 yr (611 days) |
| Mean Motion: | / day |
| Inclination: | 5.3027° |
| Asc Node: | 320.79° |
| Arg Peri: | 208.11° |
| Moid: | 0.0004 AU (0.2 LD) |
| Mean Diameter: | 7 m 20 m |
| Albedo: | >0.18 ~1 |
| Abs Magnitude: | 26.0 |
is a very bright micro-asteroid, classified as a near-Earth object of the Apollo group, less than 20m (70feet) in diameter. It was first observed by astronomers of the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, on 4 February 2018, during its sub-lunar close encounter with Earth.
On 9 February 2018, the asteroid passed about 64500km (40,100miles) from Earth, traveling 10mi/s relative to Earth and briefly reaching apparent magnitude 13.[1] It was observed by the Goldstone Observatory, which constrained its size to no more than 20 meters.[2]
During the flyby its period was changed from 1.48 years to 1.67 years.
's orbit is in Earth's neighborhood, so it frequently makes other close approaches to Earth like the 2018 one, although not usually as close. In 1953 (65 years or 44 orbits earlier), it passed 0.0065AU from Earth, and in 2090 it will pass between 0.00475AU and 0.00798AU from Earth.
It also may have passed similarly near Earth in 1914, but the uncertainty in the 1953 approach makes it difficult to determine.
appears unusually bright for its size, suggesting it is made of brighter materials than the average asteroid.