1998 KY26

Template:Mp is a nearly spherical sub-kilometer asteroid, classified as a near-Earth object of the Apollo group. It measures approximately Template:Convert in diameter and is a fast rotator, having a rotational period of only 5.35 minutes.<ref name="Santana-Ros-2025" /> It was first observed on 2 June 1998, by the Spacewatch survey at Kitt Peak National Observatory during 6 days during which it passed 800,000 kilometers (half a million miles) away from Earth (a little more than twice the Earth–Moon distance).<ref name="MPC-1998KY26" /><ref name=spacewatch />

The object's orbit is well known, since it was recovered in 2002 by the Hawaiian Observatory, and it was most recently observed, from 17 April 2024 through 3 June 2024, by several observatories.<ref name="MPC-1998KY26" />

Orbit and classification

Template:Mp orbits the Sun at a distance of 1.0–1.5 AU once every 16 months (500 days). Its orbit has an eccentricity of 0.20 and an inclination of 1° with respect to the ecliptic. It has an Earth minimum orbital intersection distance of approximately Template:Convert, corresponding to 0.98 lunar distances.<ref name="jpldata" />

As a result, it is one of the most easily accessible objects in the Solar System,<ref name=depaul>Template:Cite web</ref> and its orbit frequently brings it on a path very similar to the optimum Earth–Mars transfer orbit.<ref name="jpldata" /> This, coupled with its high water content, makes it an attractive target for further study and a potential source of water for future missions to Mars.<ref name="APOD" />

Physical properties

The physical properties of this object were measured by an international team of astronomers led by Dr. Steven J. Ostro of the Jet Propulsion Laboratory using a radar telescope in California and optical telescopes in the Czech Republic, Hawaii, Arizona and California.

Template:Mp is characterized as a potentially metallic X-type asteroid.<ref name="lcdb" /> Optical and radar observations indicate that it is a water-rich object.<ref name="APOD" />

From light curve photometry in 1998, the object is measured to have a rotation period of only 10.7 minutes, which was considered to be one of the shortest sidereal days of any known Solar System object at the time; most asteroids with established rotational rates have periods measured in hours.<ref name="Ostro-1999" /> As a result, it cannot possibly be a rubble pile, as many asteroids are thought to be, and must instead be a monolithic object.<ref name="Hicks-1998" /><ref name="Ostro-1999" /><ref name="Pravec-1998" /> It was the first such object to be discovered, but since 1998, several other small asteroids have been found to also have short rotation periods, some even faster than Template:Mp. Being a rotating body in space, it is subject to the Yarkovsky effect. Observations of the asteroid during a close approach to Earth in 2024 revealed a smaller diameter of 11 meters, a shorter rotation period of 5.35 minutes, and a brighter albedo of 0.52.

Exploration

File:Animation of Hayabusa2 orbit - extended mission.webm In September 2020, a mission extension for JAXA's Hayabusa2 asteroid sample return probe was selected to do additional flybys of two near-Earth asteroids: 98943 Torifune in July 2026 and a rendezvous with Template:Mp in July 2031. The rendezvous with Template:Mp will be the first visit of a rapidly rotating micro-asteroid.<ref name="Gough2020"/> This will also make Template:Mp the smallest object to ever be studied by a spacecraft.<ref>Template:Cite web</ref> Observations of the asteroid in 2024 cast doubt on if a landing on the asteroid is even possible.<ref name="jpldata" />

Further reading

• Template:Cite journal

External links

• MPEC 1998-L02
• Scott Hudson's Homepage: The Earth-Crossing Asteroid Template:Mp
• Steven Ostro's Homepage: Template:Mp
• Template:Cite web
• Media Relations Office. Sun never sets, for long, on fast-spinning, water-rich asteroid (press release). Pasadena, California: Jet Propulsion Laboratory. 22 July 1999.
• Template:NeoDys
• Template:ESA-SSA
• Template:JPL small body