C/2022 E3 (ZTF)

C/2022 E3 (ZTF)
	C/2022 E3 (ZTF) on 27 January 2023
Discovery
Discovered by	Zwicky Transient Facility
Discovery date	2 March 2022
Orbital characteristics
Observation arc	456 days
Number of; observations	3382
Orbit type	Long-period comet
Aphelion	≈2800 AU (barycentric epoch 1950)
Perihelion	1.112 AU
Eccentricity	0.999988 (barycentric epoch 2050)
Orbital period	≈50,000 yr (inbound); Possible Ejection (outbound)
Inclination	109.17°
Last perihelion	12 January 2023
Earth MOID	0.221 AU (33.1 million km)
Jupiter MOID	1.743 AU (260.7 million km)
Physical characteristics
Dimensions	≈1 km
Comet total; magnitude (M1)	10.5±0.6

C/2022 E3 (ZTF) is a non-periodic comet from the Oort cloud that was discovered by the Zwicky Transient Facility (ZTF) on 2 March 2022.^[1] The comet has a bright green glow around its nucleus, due to the effect of sunlight on diatomic carbon and cyanogen.^[6]^[5] The comet's systematic designation starts with C to indicate that it is not a periodic comet, and "2022 E3" means that it was the third comet to be discovered in the first half of March 2022.^[5]

The comet nucleus was estimated to be about a kilometer in size,^[7] rotating every 8.5^[8] to 8.7 hours.^[9] Its tails of dust and gas extended for millions of kilometers and, during January 2023, an anti-tail was also visible.^[10]

The comet reached its perihelion on 12 January 2023, at a distance of 1.11 AU (166 million km; 103 million mi), and the closest approach to Earth was on 1 February 2023, at a distance of 0.28 AU (42 million km; 26 million mi). The comet reached magnitude 5 and was visible with the naked eye under moonless dark skies.^[11]^[12]^[13]^[14]

^ ^a ^b Cite error: The named reference MPEC2022-F13 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference pre-perihelion-barycenter was invoked but never defined (see the help page).
^ ^a ^b ^c ^d "JPL Small-Body Database Browser: C/2022 E3". JPL. Archived from the original on 19 January 2023. Retrieved 24 August 2022.
^ ^a ^b Cite error: The named reference post-perihelion-barycenter was invoked but never defined (see the help page).
^ ^a ^b ^c "A rare green comet is becoming visible in northern skies. How to see it without a telescope". www.usatoday.com. 15 January 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.
^ Georgiou, Aristos (10 January 2023). "What makes the green comet green?". Newsweek. Archived from the original on 25 January 2023. Retrieved 25 January 2023.
^ "Once in 50,000-year comet may be visible to the naked eye". France 24. 7 January 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.
^ "ATel #15909: Rotation period and Morphological Structures in the inner coma of comet C/2022 E3 (ZTF)". The Astronomer's Telegram. Retrieved 22 February 2023.
^ "ATel #15879: Rotation period of comet C/2022 E3 ZTF from CN morphology". The Astronomer's Telegram. 30 January 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.
^ "Understanding the Tails of Comet ZTF (C/2022 E3)". Sky & Telescope. 1 February 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.
^ Cite error: The named reference COBS was invoked but never defined (see the help page).
^ Cite error: The named reference S&T20230116 was invoked but never defined (see the help page).
^ Hall, Shannon (20 January 2023). "How to Watch the 'Green Comet' in Night Skies. - Comment". The New York Times. Archived from the original on 24 January 2023. Retrieved 21 January 2023.
^ Mack, Eric (23 January 2023). "Bright Green Comet Passing Earth Is Visible Now in Dark Skies". CNET. Archived from the original on 23 January 2023. Retrieved 24 January 2023.

[MPEC2022-F13-1] Cite error: The named reference MPEC2022-F13 was invoked but never defined (see the help page).

[pre-perihelion-barycenter-2] Cite error: The named reference pre-perihelion-barycenter was invoked but never defined (see the help page).

[jpldata-3] "JPL Small-Body Database Browser: C/2022 E3". JPL. Archived from the original on 19 January 2023. Retrieved 24 August 2022.

[post-perihelion-barycenter-4] Cite error: The named reference post-perihelion-barycenter was invoked but never defined (see the help page).

[UT-5] "A rare green comet is becoming visible in northern skies. How to see it without a telescope". www.usatoday.com. 15 January 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.

[6] Georgiou, Aristos (10 January 2023). "What makes the green comet green?". Newsweek. Archived from the original on 25 January 2023. Retrieved 25 January 2023.

[7] "Once in 50,000-year comet may be visible to the naked eye". France 24. 7 January 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.

[8] "ATel #15909: Rotation period and Morphological Structures in the inner coma of comet C/2022 E3 (ZTF)". The Astronomer's Telegram. Retrieved 22 February 2023.

[9] "ATel #15879: Rotation period of comet C/2022 E3 ZTF from CN morphology". The Astronomer's Telegram. 30 January 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.

[10] "Understanding the Tails of Comet ZTF (C/2022 E3)". Sky & Telescope. 1 February 2023. Archived from the original on 2 February 2023. Retrieved 2 February 2023.

[COBS-11] Cite error: The named reference COBS was invoked but never defined (see the help page).

[S&T20230116-12] Cite error: The named reference S&T20230116 was invoked but never defined (see the help page).

[NYT-20230120-13] Hall, Shannon (20 January 2023). "How to Watch the 'Green Comet' in Night Skies. - Comment". The New York Times. Archived from the original on 24 January 2023. Retrieved 21 January 2023.

[14] Mack, Eric (23 January 2023). "Bright Green Comet Passing Earth Is Visible Now in Dark Skies". CNET. Archived from the original on 23 January 2023. Retrieved 24 January 2023.

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