The 469219 Kamo’oalewa, tentatively called the 2016 HO3, is a very small asteroid, fast rotor, and near-Earth object of the Apollo Group, about 41 meters in diameter. It is currently the Earth’s quasi-satellite and is currently the smallest, closest and most stable (known) of such quasi-satellites.
Discovery of Kamo’oalewa
In the year 2016, Pan-STARRS at Haleakala Observatory discovered this asteroid. It was called Kamo’oalewa,, which refers to a vibrating celestial body in Hawaiian. Earth-like orbits and moon-like silicates can be the result of lunar ejecta.
Asteroid survey telescope, Pan-STARRS 1 in Haleakala, Hawaii is operated by the University of Hawaii’s Institute of Astronomy and is funded by Planetary Defense Coordination Office of NASA. The name Kamo’oalewa comes from the Hawaiian words ka and mo’o’ fragment’. This refers to the fact that it is a separate part from the larger objects and lewa is its movement in heaven when viewed from the earth. The official name quote was published by the Asteroid Center on April 6, 2019.
Orbit
It orbits the sun at a distance of 0.90 to 1.10 AU. The period as of 2022 is about 366 days, but since it is a quasi-satellite of the earth and lasts for hundreds of years, the long-term average period will be close to 365 days. Its orbit has an inclination of 8 and an eccentricity of 0.10 with respect to the ecliptic. The minimum orbit intersection distance is 0.033 AU (4.9 million km), which is equivalent to 13 lunar distances. However, 13 LD is far outside the hills of the Earth, 1.5 million kilometers.
When orbiting the sun, Kamo’oalewa also appears to orbit the earth (strongly oval). The object is outside the Earth’s hill sphere, and the Sun exerts much stronger force than the Earth. This is the most stable example of a near-Earth object or quasi-satellite to date.
In the annual movement around the Sun, it spends about half of the time closer to the Sun than the Earth and swaying because the orbit is slightly tilted. This little asteroid orbit the Earth once a year and is trapped in a game of jumping with the Earth that has lasted for hundreds of years.
Physical Characteristics of 469219 Kamo’oalewa
The size is not yet well established, but it is about 40-100 m. Based on a 0.20 stone S-type asteroid and an assumed standard albedo of 24.3 absolute brightness, it measures a diameter of 41 meters. Photometric observations showed that the Kamo’oalewa is a high-speed rotor. Light curve analysis showed a rotation period of 0.467 0.008 hours and a change in brightness of 0.80 0.05 digits. In the year 2021, a comprehensive physical characterization was performed using the Lowell Discovery Telescope and the Large Binocular Telescope, where the asteroid was composed of lunar-like silicates and was impacted from the moon.
Proposed Missions
A team of research assistants from Colorado Boulder University and Sao Paulo State University were invited to Characterize and Observe asteroids near the Earth and to provide the first baseline for exploring this object on a spacecraft. Another version of this work was recently announced, which undertakes other limitations of dynamics. China National Space Administration is planning a robotic mission to bring back samples. The start of this mission by ZhengHe is currently planned for the year 2025.
