2022 UR₄

2022 UR₄
Discovery
Discovered by	ATLAS-MLO
Discovery site	Mauna Loa Obs.
Discovery date	20 November 2022
Designations
MPC designation	2022 WM7
Alternative designations	A10OBKV
Minor planet category	NEO · Apollo
Orbital characteristics
	Epoch 25 February 2023 (JD 2460000.5)
	Uncertainty parameter 6
Observation arc	13.56 hours
Aphelion	2.701 AU
Perihelion	0.831 AU
Semi-major axis	1.766 AU
Eccentricity	0.5294
Orbital period (sidereal)	2.35 yr (857.0 days)
Mean anomaly	36.030°
Mean motion	0° 25m 12.279s / day
Inclination	11.292°
Longitude of ascending node	207.182°
Time of perihelion	December 2022
Argument of perihelion	238.577°
Earth MOID	0.000407 AU (60,900 km; 0.158 LD)
Jupiter MOID	2.641 AU
Physical characteristics
Mean diameter	4.4–9.9 m (assumed albedo 0.05–0.25)
Absolute magnitude (H)	28.90±0.45

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2022 UR₄ is a small near-Earth asteroid that made an extremely close approach within 0.044 lunar distances (17,000 km; 11,000 mi) from Earth's center on 20 October 2022 at 22:45 UTC.^[4] It was discovered about 14 hours before closest approach by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey telescope at Mauna Loa Observatory, Hawaii on 20 November 2022.^[2] During the close approach, the asteroid passed above the northern hemisphere of Earth and reached a peak brightness of magnitude 10,^[2] just 40 times fainter than the threshold of naked eye visibility.^[a]

Notes

^ The faintest magnitude that can be seen with the naked eye is about 6.^[6] Using the formula $Δ m = -2.5 log 10 (F 1 / F 2)$ ,^[6] where $Δ m = m 1 - m 2 = 6 - 10 = -4$ is the magnitude difference between the naked eye limit and 2022 UR₄'s peak brightness, the brightness ratio $F 1 / F 2$ of the naked eye limit to the peak brightness of 2022 UR₄ is approximately $39.81 \approx F 1 / F 2 = 10 (Δ m /-2.5)$ .

References

^ ^a ^b ^c "2022 UR4". Minor Planet Center. Retrieved 30 November 2022.
^ ^a ^b ^c "MPEC 2022-U145 : 2022 UR4". Minor Planet Electronic Circular. Minor Planet Center. 21 October 2022. Retrieved 30 November 2022.
^ "2022 UR4". NEO Exchange. Las Cumbres Observatory. 20 October 2022. Retrieved 30 November 2022.
^ ^a ^b ^c ^d "JPL Small-Body Database Browser: (2022 UR4)" (2022-10-20 last obs.). Jet Propulsion Laboratory. Retrieved 30 November 2022.
^ "Asteroid Size Estimator". Center for Near Earth Object Studies. NASA. Retrieved 30 November 2022.
^ ^a ^b Mihos, Chris (2005). "The Magnitude Scale". Case Western Reserve University. Retrieved 30 November 2022.

External links

2022 UR4 at NeoDyS-2, Near Earth Objects—Dynamic Site
- Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
2022 UR4 at ESA–space situational awareness
- Ephemerides · Observations · Orbit · Physical properties · Summary
2022 UR4 at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

[magnitude-7] The faintest magnitude that can be seen with the naked eye is about 6.^[6] Using the formula $Δ m = -2.5 log 10 (F 1 / F 2)$ ,^[6] where $Δ m = m 1 - m 2 = 6 - 10 = -4$ is the magnitude difference between the naked eye limit and 2022 UR₄'s peak brightness, the brightness ratio $F 1 / F 2$ of the naked eye limit to the peak brightness of 2022 UR₄ is approximately $39.81 \approx F 1 / F 2 = 10 (Δ m /-2.5)$ .

[MPC-object-1] "2022 UR4". Minor Planet Center. Retrieved 30 November 2022.

[MPEC-2022-U145-2] "MPEC 2022-U145 : 2022 UR4". Minor Planet Electronic Circular. Minor Planet Center. 21 October 2022. Retrieved 30 November 2022.

[NEOExchange-3] "2022 UR4". NEO Exchange. Las Cumbres Observatory. 20 October 2022. Retrieved 30 November 2022.

[jpldata-4] "JPL Small-Body Database Browser: (2022 UR4)" (2022-10-20 last obs.). Jet Propulsion Laboratory. Retrieved 30 November 2022.

[sizeestimator-5] "Asteroid Size Estimator". Center for Near Earth Object Studies. NASA. Retrieved 30 November 2022.

[magnitude-6] Mihos, Chris (2005). "The Magnitude Scale". Case Western Reserve University. Retrieved 30 November 2022.

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