Editing Apollo asteroid (section)

{{Short description|Group of near-Earth asteroids}}
[[File:Neo orbit types.jpg|thumb|upright=2.4|Common orbital subgroups of [[Near-Earth Object]]s (NEOs)]]

The '''Apollo asteroids''' are a group of [[near-Earth asteroid]]s named after [[1862 Apollo]], discovered by German astronomer [[Karl Reinmuth]] in the 1930s. They are [[Earth-crosser asteroid|Earth-crossing asteroid]]s that have an orbital [[semimajor axis|semi-major axis]] greater than that of the Earth (a &gt; 1 [[Astronomical unit|AU]]) but [[perihelion]] distances less than the Earth's [[aphelion]] distance (q < 1.017 AU).<ref name="NEO-groups" /><ref name="Wolfram-Apollo" />

{{As of|2025|01}}, the number of known Apollo asteroids is 21,083, making the class the largest group of [[near-Earth object]]s (''cf''. the [[Aten asteroid|Aten]], [[Amor asteroid|Amor]] and [[Atira asteroid|Atira]] asteroids), of which 1,742 are [[Minor planet designation|numbered]] (asteroids are not numbered until they have been observed at two or more [[Opposition (planets)|oppositions]]), 81 are named, and 2,130 are identified as [[potentially hazardous asteroids]].<ref name="ssd-jpl">{{cite web |title=Small-Body Database Query |url=https://ssd.jpl.nasa.gov/tools/sbdb_query.html#!#results |website=Solar System Dynamics – Jet Propulsion Laboratory |publisher=NASA – California Institute of Technology |access-date=2025-01-17}}</ref><ref>{{cite web |title=List of Apollo Minor Planets |url=https://minorplanetcenter.net/iau/lists/Apollos.html |website=IAU Minor Planet Center |publisher=Center for Astrophysics |access-date=2025-01-17}}</ref>

The closer their semi-major axis is to Earth's, the less [[Eccentricity (orbit)|eccentricity]] is needed for the [[orbit]]s to cross. The [[Chelyabinsk meteor]], that exploded over the city of [[Chelyabinsk#2013 meteor|Chelyabinsk]] in the southern Urals region of Russia on February 15, 2013, injuring an estimated 1,500 people with flying glass from broken windows, was an Apollo-class [[asteroid]].<ref name="USA-Today-Chelyabinsk" /><ref name="NewScientist-Chelyabinsk" />