Earth to Get ‘Second Quasi-Moon’ by 2083
- Astronomers have confirmed that a small, rocky object, designated 469219 kamoʻoalewa, is a quasi-satellite of Earth, meaning it orbits the Sun while remaining in a stable configuration relative...
- Kamoʻoalewa was first discovered on april 25, 2016, by the Pan-STARRS telescope at the University of hawaii's Institute for Astronomy.
- initial observations indicated Kamoʻoalewa's orbit was not typical of an asteroid.
Quasi-Satellite of Earth, Kamoʻoalewa (469219)
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Astronomers have confirmed that a small, rocky object, designated 469219 kamoʻoalewa, is a quasi-satellite of Earth, meaning it orbits the Sun while remaining in a stable configuration relative to our planet. This object has been traveling with earth for at least several decades, largely unnoticed untill recently.
Discovery and Initial Observations
Kamoʻoalewa was first discovered on april 25, 2016, by the Pan-STARRS telescope at the University of hawaii’s Institute for Astronomy. Its unusual orbit and composition instantly sparked interest among researchers. The name “kamoʻoalewa” comes from Hawaiian mythology, meaning “oscillator” or “trembling celestial body,” referencing its orbital characteristics.
initial observations indicated Kamoʻoalewa’s orbit was not typical of an asteroid. It doesn’t follow a standard path around the Sun, but rather loops around Earth in a complex dance. Further study revealed it’s a quasi-satellite,a type of celestial body that has a stable orbital relationship with a planet but isn’t gravitationally bound to it like a moon.
Orbital Characteristics and Stability
A quasi-satellite’s orbit is similar to that of a planet, but with a slight variation. Kamoʻoalewa’s orbit takes approximately one year,similar to Earth’s,but it’s slightly more elongated. This allows it to remain in a relatively stable configuration with Earth over long periods.Researchers estimate Kamoʻoalewa has been in this quasi-satellite relationship with Earth for at least several centuries, and possibly much longer.
The object’s distance from Earth varies,ranging from about 9.3 million miles (15 million kilometers). Its orbit is not perfectly stable; it slowly drifts away from Earth, but it will likely remain a quasi-satellite for several more centuries before eventually moving on.
Composition and Potential Origin
Determining Kamoʻoalewa’s composition has been a key focus of research. Spectroscopic analysis suggests its surface is remarkably similar to lunar material. A study published in Nature Communications in 2023 proposes that Kamoʻoalewa might potentially be a fragment of the moon, ejected during an impact event. The research team, led by Benjamin Šmilauer at the University of Hawaii, found that Kamoʻoalewa’s spectral signature closely matches lunar samples returned by the Apollo missions.
This lunar origin hypothesis is supported by the object’s orbital characteristics. The way Kamoʻoalewa orbits suggests it didn’t form in its current location but was captured by Earth’s gravitational influence after being ejected from the Moon. The team estimates that approximately 1.4% of lunar material ejected during impacts could become quasi-satellites of Earth.
Future Research and Observation
Further research is planned to confirm Kamoʻoalewa’s lunar origin and to better understand its orbital dynamics. The OSIRIS-REx mission, after successfully delivering a sample from asteroid bennu, is being repurposed to study Kamoʻoalewa. NASA announced in September 2023 that OSIRIS-REx will be renamed OSIRIS-APEX and will arrive at Kamoʻoalewa in 2029 to conduct a detailed investigation of its composition and structure.
The OSIRIS-APEX mission aims to provide definitive evidence regarding Kamoʻoalewa’s origin and will offer valuable insights into the processes that shape the Earth-Moon system. The mission will also help scientists understand the potential for other lunar fragments to become quasi-satellites of Earth.