The Worst Moons in the Solar System

[Prometheus]

Now’s your chance as well as saying your favorite in that other thread I did, to tell me how much you hate a/some particular moon/s. I wonder how this will end up.

[neufer]

• 469219 Kamoʻoalewa [note: 469219 is a prime number]

Kamoʻoalewa orbit relative to Sun & Earth from 1600 to 2500

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<<469219 Kamoʻoalewa, provisionally designated 2016 HO3, is a very small asteroid, fast rotator and near-Earth object of the Apollo group, approximately 41 meters in diameter. Currently, it is the smallest, closest, and most stable (known) quasi-satellite of Earth. Photometric observations in April 2017 revealed that Kamoʻoalewa is a fast rotator. Lightcurve analysis gave a rotation period of 0.467 ± 0.008 hours (28.02 ± 0.48 minutes) and a brightness variation of 0.80±0.05 magnitude. In 2021, a comprehensive physical characterization of Kamoʻoalewa was conducted using the Large Binocular Telescope and the Lowell Discovery Telescope, which found that the asteroid is composed of lunar-like silicates and may be an impact fragment from the Moon. Kamoʻoalewa orbits the Sun at a distance of 0.90–1.10 AU once every 366 days. Its orbit has an eccentricity of 0.10 and an inclination of 8° with respect to the ecliptic. It has an Earth minimum orbital intersection distance of 0.0348 AU (5,210,000 km) that translates into 13.6 lunar distances. As it orbits the Sun, Kamoʻoalewa appears to circle (highly elliptically) around Earth as well. The object is beyond the Hill sphere of Earth and the Sun exerts a much stronger pull on it than Earth does. Although it is too distant to be considered a true natural satellite of Earth, it is the best and most stable example to date of a near-Earth companion, or quasi-satellite.

Kamoʻoalewa was first spotted on 27 April 2016, by the Pan-STARRS 1 asteroid survey telescope on Haleakalā, Hawaii, that is operated by the University of Hawaii's Institute for Astronomy and funded by NASA's Planetary Defense Coordination Office. The name Kamoʻoalewa is derived from the Hawaiian words ka 'the', moʻo 'fragment', referring to it being a piece broken off a larger object, a 'of', and lewa 'to oscillate', referring to its motion in the sky as viewed from Earth.

Paul Chodas, manager of NASA's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California, commented on the orbit: "Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the Sun, we refer to it as a quasi-satellite of Earth. One other asteroid – 2003 YN107 – followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth's companion for centuries to come."

Chodas explained how the asteroid's orbit also undergoes a slow, back-and-forth twist over multiple decades: "The asteroid's loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth's gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon.

The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth."

[orin stepanek]

The Martian moons!

[neufer]

The Wurst Asteroid in the Solar System!

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<<25143 Itokawa is a sub-kilometer near-Earth object of the Apollo group and a potentially hazardous asteroid. It was discovered by the LINEAR program in 1998 and later named after Japanese rocket engineer Hideo Itokawa. The peanut-shaped S-type asteroid has a rotation period of 12.1 hours and measures approximately 330 meters in diameter. Due to its low density and high porosity, Itokawa is considered to be a rubble pile, consisting of numerous boulders of different sizes rather than of a single solid body.

25143 Itokawa was the first asteroid to be the target of a sample return mission, the Japanese space probe Hayabusa, which collected more than 1500 regolith dust particles from the asteroid's surface in 2005. After its return to Earth in 2010, the mineralogy, petrography, chemistry, and isotope ratios of these particles have been studied in detail, providing insights into the evolution of the Solar System. Itokawa is the smallest asteroid ever photographed and visited by a spacecraft. The 26 August 2011 issue of Science devoted six articles to findings based on dust that Hayabusa had collected from Itokawa. Scientists' analysis suggested that Itokawa was probably made up from interior fragments of a larger asteroid that broke apart. Dust collected from the asteroid surface is thought to have been exposed there for about eight million years.

Itokawa's composition was found to match the common type of meteorites known as "low-total-iron, low metal ordinary chondrites". [Ironically, Liverwurst, itself, is rich in iron.] Another team of scientists determined that the dark iron color on the surface of Itokawa was the result of abrasion by micrometeoroids and high-speed particles from the Sun which had converted the normally whitish iron oxide coloring.

Two separate groups report water in different Itokawa particles. Jin et al. report water in low-calcium pyroxene grains. The water's isotope level corresponds with inner Solar System and carbonaceous chondrite water isotope levels. Daly et al. report "OH and H₂O" apparently formed by implantation of solar wind hydrogen. The rims of an olivine particle "show an enrichment of up to ~1.2 at % in OH and H₂O". The water concentrations of the Itokawa grains would indicate an estimated BSI (Bulk Silicate Itokawa) water content in line with Earth's bulk water, and that Itokawa had been a "water-rich asteroid".>>

[Prometheus]

• 469219 Kamoʻoalewa [note: 469219 is a prime number]

Kamoʻoalewa orbit relative to Sun & Earth from 1600 to 2500

---

<<469219 Kamoʻoalewa, provisionally designated 2016 HO3, is a very small asteroid, fast rotator and near-Earth object of the Apollo group, approximately 41 meters in diameter. Currently, it is the smallest, closest, and most stable (known) quasi-satellite of Earth. Photometric observations in April 2017 revealed that Kamoʻoalewa is a fast rotator. Lightcurve analysis gave a rotation period of 0.467 ± 0.008 hours (28.02 ± 0.48 minutes) and a brightness variation of 0.80±0.05 magnitude. In 2021, a comprehensive physical characterization of Kamoʻoalewa was conducted using the Large Binocular Telescope and the Lowell Discovery Telescope, which found that the asteroid is composed of lunar-like silicates and may be an impact fragment from the Moon. Kamoʻoalewa orbits the Sun at a distance of 0.90–1.10 AU once every 366 days. Its orbit has an eccentricity of 0.10 and an inclination of 8° with respect to the ecliptic. It has an Earth minimum orbital intersection distance of 0.0348 AU (5,210,000 km) that translates into 13.6 lunar distances. As it orbits the Sun, Kamoʻoalewa appears to circle (highly elliptically) around Earth as well. The object is beyond the Hill sphere of Earth and the Sun exerts a much stronger pull on it than Earth does. Although it is too distant to be considered a true natural satellite of Earth, it is the best and most stable example to date of a near-Earth companion, or quasi-satellite.

Kamoʻoalewa was first spotted on 27 April 2016, by the Pan-STARRS 1 asteroid survey telescope on Haleakalā, Hawaii, that is operated by the University of Hawaii's Institute for Astronomy and funded by NASA's Planetary Defense Coordination Office. The name Kamoʻoalewa is derived from the Hawaiian words ka 'the', moʻo 'fragment', referring to it being a piece broken off a larger object, a 'of', and lewa 'to oscillate', referring to its motion in the sky as viewed from Earth.

Paul Chodas, manager of NASA's Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California, commented on the orbit: "Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the Sun, we refer to it as a quasi-satellite of Earth. One other asteroid – 2003 YN107 – followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth's companion for centuries to come."

Chodas explained how the asteroid's orbit also undergoes a slow, back-and-forth twist over multiple decades: "The asteroid's loops around Earth drift a little ahead or behind from year to year, but when they drift too far forward or backward, Earth's gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the moon.

The same effect also prevents the asteroid from approaching much closer than about 38 times the distance of the moon. In effect, this small asteroid is caught in a little dance with Earth."

That orbit…it bugs me. And who the heck names a “moon” (more like quasi moon) “Kamo’oalewa”?

[neufer]

Click to play embedded YouTube video.

...who the heck names a “moon” (more like quasi moon) “Kamo’oalewa”?

<<Kamoʻoalewa alludes to a celestial object that is oscillating, like its path in the sky as viewed from the Earth. It is a name found in the Hawaiian chant Kumulipo. Name conceived by A Hua He Inoa, ʻImiloa Astronomy Center of Hawaiʻi.>>