2020 HS7

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 byPan-STARRS 2
Discovery siteHaleakala Obs.
Discovery date27 April 2020
Designations
2020 HS7
NEO · Apollo[3][1]
Orbital characteristics[3]
Epoch 9 August 2022 (JD 2459800.5)
Uncertainty parameter 6
Observation arc1 day
Aphelion2.904 AU
Perihelion0.793 AU
1.849
Eccentricity0.5709
2.51 yr (918 days)
308.988°
0° 23m 31.807s / day
Inclination4.732°
38.531°
245.692°
Physical characteristics
Dimensionsa/b = ≥1.04[4]
Mean diameter
4–8 m[5]
2.9945±0.0002 s[4]
2.9938±0.0002 s[4]
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.[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

    References
    1. "2020 HS7". Minor Planet Center. Retrieved 15 July 2022.
    2. "MPEC 2022-F48 : 2022 FD1". Minor Planet Electronic Circular. Minor Planet Center. 28 April 2020. Retrieved 15 July 2022.
    3. "JPL Small-Body Database Browser: (2020 HS7)" (2022-04-28 last obs.). Jet Propulsion Laboratory. Retrieved 29 July 2020.
    4. Beniyama, Jin; et al. (2022). "Video observations of tiny near-Earth objects with Tomo-e Gozen". Publications of the Astronomical Society of Japan. 74 (4): 877–903. arXiv:2207.07071. doi:10.1093/pasj/psac043.
    5. Bartels, Meghan (5 May 2020). "Tiny asteroid's super-close Earth flyby shows planetary protection in action, scientists say". Space.com.
    6. "ESA space situational awareness 2020HS7". European Space Agency. Retrieved 29 July 2020.
    7. Malik, Tariq (28 April 2020). "Small asteroid zips safely by Earth just ahead of a larger space rock's flyby". Space.com.
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