asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
near-Earth object
A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...
of the Apollo group, approximately in diameter. At present it is a quasi-satellite of Earth, and currently the second-smallest, closest, and most stable known such quasi-satellite (after ).
The asteroid was discovered by
Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical ...
at Haleakala Observatory on 27 April 2016. Numerous proposed missions have since targeted the object, including a NASA solar-sail mission,Heiligers, J., Fernandez, J. M., Stohlman, O. R., & Wilkie, W. K. (2019). Trajectory design for a solar-sail mission to asteroid 2016 HO3. Astrodynamics, 3(3), 231-246. https://doi.org/10.1007/s42064-019-0061-1 a University of Colorado flyby and impact experiment, and was selected as a target for the Chinese ZhengHe project, which has developed into the Tianwen-2 mission. The chondriticsimulants QLS-1, 2, and 3 have been developed by the Qian Xuesen Laboratory of Space Technology to better prepare for these missions. In an ambitious proposal, 469219 Kamo'oalewa is even considered for use as a space station for Earth-to-Mars travel.Fargion, D. (2022). Mini-moon, Kamo'oalewa: The Future Space Station 44th COSPAR Scientific Assemly, https://ui.adsabs.harvard.edu/abs/2022cosp...44..215F/abstract
The object's Earth-like orbit, proximity to the Earth-Moon system, higher spectral reddening to other asteroids, and similarity to space weathered lunar materials indicate that it is likely lunar
ejecta
Ejecta (; ) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic rock, pyroclastic materials (tephra) that came out of a explosive eruption, volcanic explosion and magma eruption v ...
.Castro-Cisneros, J. D., Malhotra, R., & Rosengren, A. J. (2023). Lunar ejecta origin of near-Earth asteroid Kamo'oalewa is compatible with rare orbital pathways. Commun Earth Environ, 4(1), 372. https://doi.org/10.1038/s43247-023-01031-w However, it might also be an S-type or L-type asteroid.Reddy, V., Kuhn, O., Thirouin, A., Conrad, A., Malhotra, R., Sanchez, J., & Veillet, C. (2017). Ground-based Characterization of Earth Quasi Satellite (469219) 2016 HO3 49th AAS-DPS Meeting, https://ui.adsabs.harvard.edu/abs/2017DPS....4920407R/abstractFenucci, M., & Novaković, B. (2021). The Role of the Yarkovsky Effect in the Long-term Dynamics of Asteroid (469219) Kamo'oalewa. The Astronomical Journal, 162(6). https://doi.org/10.3847/1538-3881/ac2902 Despite being most similar to weathered Apollo 14 and Luna 24 Lunar Mare soils, it is suggested to be from the lunar far-side highland crust crater,
Giordano Bruno
Giordano Bruno ( , ; ; born Filippo Bruno; January or February 1548 – 17 February 1600) was an Italian philosopher, poet, alchemist, astrologer, cosmological theorist, and esotericist. He is known for his cosmological theories, which concep ...
.
Orbital similarities suggest it is likely a co-orbital pair with 2000 WN10Dermawan, B. (2019). Temporal Earth Coorbital Types of Asteroid 2016 HO3. Paper No. 012038 6th International Conference on Mathematics & Natural Sciences 2019. IOP Publishing. DOI: 10.1088/1742-6596/1127/1/012038 or a broken up set including the other NEOs 2020 KZ2, 2020 PN1, and 2020 PP1.
Discovery and naming
Kamooalewa was first spotted on 27 April 2016, by the
Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical ...
1 asteroid survey telescope on Haleakalā, Hawaii, that is operated by the
University of Hawaii
A university () is an educational institution, institution of tertiary education and research which awards academic degrees in several Discipline (academia), academic disciplines. ''University'' is derived from the Latin phrase , which roughly ...
's Institute for Astronomy and funded by NASA's Planetary Defense Coordination Office. It was named in 2019 , from the Hawaiian chant Kumulipo for an oscillating celestial object by A Hua He Ino at the 'Imiloa Astronomy Center of Hawai'i.
The name Kamooalewa is derived from the Hawaiian words ''ka'' 'the', ''moo'' '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. The official was published by the
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory.
Funct ...
Kamooalewa orbits the Sun at a distance of 0.90–1.10 AU. Although the period as of 2022 is about 366 days, its longer-term average period is closer to 365 days. 469219 Kamooalewa is a quasi-moon and not gravitationally bound to Earth like a true satellite. Its orbit transfers between a Quasi satellite orbit type which resides in the L1 and L2
Lagrange
Joseph-Louis Lagrange (born Giuseppe Luigi LagrangiaHorseshoe orbit between the L4 and L5 Lagrange points.Qi, Y., & Qiao, D. (2022). Co-orbital transition of 2016 HO3. Astrodynamics, 7(1), 3-14. https://doi.org/10.1007/s42064-021-0122-0
Its orbit has an
eccentricity
Eccentricity or eccentric may refer to:
* Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal"
Mathematics, science and technology Mathematics
* Off-Centre (geometry), center, in geometry
* Eccentricity (g ...
of 0.10 and an inclination of 8 ° with respect to the
ecliptic
The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making.
Fr ...
Hill sphere
The Hill sphere is a common model for the calculation of a Sphere of influence (astrodynamics), gravitational sphere of influence. It is the most commonly used model to calculate the spatial extent of gravitational influence of an astronomical ...
of .
Quasi-satellite of Earth
In a rotating frame of reference Kamooalewa appears to circle elliptically around the Earth every ~45 years. Although it is too distant to be considered a true
natural satellite
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, a deriv ...
of Earth, it is the best and most stable example to date of a near-Earth companion, or quasi-satellite. Orbital and Yarkovsky effect modeling suggest it will be stable for 0.3-0.5 million years.
Paul Chodas, manager of
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
Jet Propulsion Laboratory
The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by Cali ...
(JPL) in
Pasadena, California
Pasadena ( ) is a city in Los Angeles County, California, United States, northeast of downtown Los Angeles. It is the most populous city and the primary cultural center of the San Gabriel Valley. Old Pasadena is the city's original commerci ...
described the orbit of as a quasi-satellite of Earth. Unlike asteroid , which previously followed a similar orbit, 2016 HO3 is more stable and has been Earth's companion for more than a century and will remain so for much longer. This asteroid spends half of its orbit closer to the Sun than Earth and the other half farther away, causing it to oscillate above and below Earth's orbit annually. Its orbit experiences slight drifts that Earth's gravity corrects, keeping it between 38 and 100 times the distance of the Moon. Thus, 2016 HO3 continually dances around the Earth.
The closest Earth approach was on at . By late May 2369, the asteroid will be from Earth. The Earth-like orbit may be a result of it being lunar ejecta. Most objects in this kind of orbit are eventually perturbed out of being in an Earth-co-orbital state and hit the Earth, Venus, or the Sun or are ejected from the
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...
, and Kamooalewa will probably hit the Earth in the next 100 million years.
Physical characteristics
The size of Kamooalewa has not yet been firmly established, but it is approximately . Based on an assumed standard
albedo
Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...
Lightcurve
In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...
analysis gave a
rotation period
In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...
of and a brightness variation of magnitude ().. 2024 inversion modeling was used to create a 100m x 81m x 46m (~72m diameter) 3D model from light curve data.
In 2021, a spectroscopic characterization of Kamooalewa was conducted using the Large Binocular Telescope and the Lowell Discovery Telescope, which found that the asteroid is likely silicate in origin. The object's Earth-like orbit, proximity to the Earth-Moon system, higher spectral reddening to other asteroids, and similarity to space weathered lunar materials indicate that it is likely lunar
ejecta
Ejecta (; ) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic rock, pyroclastic materials (tephra) that came out of a explosive eruption, volcanic explosion and magma eruption v ...
. However, it might also be an S-type or L-type asteroid. Despite being most similar to weathered Apollo 14 and Luna 24 Lunar Mare soils, it is suggested to be from the lunar far-side highland crust crater,
Giordano Bruno
Giordano Bruno ( , ; ; born Filippo Bruno; January or February 1548 – 17 February 1600) was an Italian philosopher, poet, alchemist, astrologer, cosmological theorist, and esotericist. He is known for his cosmological theories, which concep ...
for its required size and Copernican age.
Lunar ejecta modeling shows some avenues that can achieve a stable QS 469219 Kamo'oalewa-style orbit.
Exploration
Tianwen-2
The
China National Space Administration
The China National Space Administration (CNSA) is a government agency of the People's Republic of China headquartered in Haidian District, Haidian, Beijing, responsible for civil space administration and international space cooperation. These ...
De la Fuente Marcos & de la Fuente Marcos first suggested in situ study of because of its ideal orbital characteristics in their August 2016 paper.
During the 2017 Astrodynamics Specialist Conference held in Stevenson in the U.S. state of Washington, a team composed of graduate research assistants from the University of Colorado Boulder and the
São Paulo State University
São Paulo State University (Unesp, ) is a public university run by the São Paulo State Government, state government of São Paulo (state), São Paulo, Brazil.
Unesp has a combined student body of over 45,000 spread among its 23 campuses. The ...
(UNESP) was awarded for presenting a project denominated "Near-Earth Asteroid Characterization and Observation (NEACO) Mission to Asteroid (469219) ", providing the first baselines for the investigation of this celestial object using a spacecraft. Recently, another version of this work was presented adopting different constraints in the dynamics.
A 2019 NASA solar sail mission proposal selected it as a target.
469219 Kamo'oalewa has been considered for use as a space station in near-Earth space.
Gallery
See also
* Arjuna asteroid
* 3753 Cruithne
* 6Q0B44E
*
*
*
*
*
*
*
*
*
* , a quasi-satellite of Venus, and the first quasi-satellite discovered around any major planet