astro.wikisort.org - Asteroid

2020 HS₇ is a very small asteroid classified as a near-Earth object of the Earth-crossing Apollo group. When it was discovered by the Pan-STARRS 2 survey on 27 April 2020, the asteroid was initially calculated to have a 10% chance of impact with Earth before being ruled out by improved orbit determinations from additional observations.[6] Although there is now no risk of impact with Earth, it did make a close approach 42,700 kilometres (26,500 mi) from Earth on 28 April 2020, with a flyby speed of 15.6 kilometres per second (9.7 mi/s) relative to Earth.[3][7][5] The asteroid will not make any close encounters within 1 lunar distance (380,000 km; 240,000 mi) of Earth in the next 100 years.[3]

2020 HS₇

Discovery[1][2]
Discovered by	Pan-STARRS 2
Discovery site	Haleakala Obs.
Discovery date	27 April 2020
Designations
MPC designation	2020 HS7
Minor planet category	NEO · Apollo[3][1]
Orbital characteristics[3]
Epoch 9 August 2022 (JD 2459800.5)
Uncertainty parameter 6
Observation arc	1 day
Aphelion	2.904 AU
Perihelion	0.793 AU
Semi-major axis	1.849
Eccentricity	0.5709
Orbital period (sidereal)	2.51 yr (918 days)
Mean anomaly	308.988°
Mean motion	0° 23m 31.807s / day
Inclination	4.732°
Longitude of ascending node	38.531°
Argument of perihelion	245.692°
Physical characteristics
Dimensions	a/b = ≥1.04[4]
Mean diameter	4–8 m[5]
Synodic rotation period	2.9945±0.0002 s[4] 2.9938±0.0002 s[4]
Absolute magnitude (H)	29.10±0.36[3]

Observations by Kiso Observatory in Nagano, Japan show that the asteroid rotates extremely rapidly with a rotation period of 3 seconds, making it the fastest-rotating asteroid known as of 2022^[update].[4] No other near-Earth asteroid of similar size is known to have a rotation period shorter than 10 seconds, which could be attributed to the tangential component of the YORP effect accelerating their rotation far beyond this period.[4] The asteroid exhibits a very small light curve amplitude of 0.07 magnitudes, which either implies a nearly spherical shape or a pole-on rotation during observations.[4]

See also

• List of fast rotators (minor planets)
• List of asteroid close approaches to Earth in 2020

References

External links

• 2020 HS7 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 2020 HS7 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 2020 HS7 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

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