&sq=Envato&lang=en&file=File:C2021_T4_2022-12-21_image_ZTF-sso-295-zg-fov-5.6arcmin.png) The comet on 21 December 2022, by ZTF | |
| Discovery[1] | |
|---|---|
| Discovered by | E. Bryssinck |
| Discovery site | Mount Lemmon Observatory |
| Discovery date | 7 October 2021 |
| Designations | |
| CK21T040 C6131F2 | |
| Orbital characteristics[3] | |
| Observation arc | 2.91 years (1,064 days) |
| Number of observations | 2,107 |
| Aphelion | ≈44,000 AU (inbound)[2] ≈2,200 AU (outbound) |
| Perihelion | 1.4833 AU |
| Semi-major axis | 48,585.76 AU |
| Eccentricity | 0.99997 |
| Orbital period | millions of years (inbound)[2] ≈36,000 years (outbound) |
| Inclination | 160.78° |
| 257.88° | |
| Argument of periapsis | 329.81° |
| Last perihelion | 31 July 2023 |
| Earth MOID | 0.4975 AU (74.42×106 km) |
| Jupiter MOID | 0.8699 AU (130.14×106 km) |
| Comet total magnitude (M1) | 6.9 |
C/2021 T4 (Lemmon) is a long period comet discovered by the Mount Lemmon Observatory on 7 October 2021.[1] This passage through the planetary region of the Solar System will reduce the orbital period from millions of years to thousands of years.[2]
It has been south of the celestial equator since October 2022. On 13 June it was 1.5 degrees from magnitude 2 Beta Ceti. Closest approach to Earth was on 20 July 2023 at a distance of 0.54 AU (81 million km).[4] The next day it reached its southernmost declination, at -56 degrees. On 25 July it passed next to the globular cluster NGC 6397.[5] It reached perihelion on 31 July 2023 at a solar distance of 1.48 AU. The comet brightened to around apparent magnitude 8.[6]
- ^ a b Cite error: The named reference
MPCwas invoked but never defined (see the help page). - ^ a b c Cite error: The named reference
barycenterwas invoked but never defined (see the help page). - ^ Cite error: The named reference
jplwas invoked but never defined (see the help page). - ^ Earth Approach 2023 (delta. Close approach occurs when deldot flips from negative to positive.)
- ^ Dickinson, David (25 July 2023). "A Fine Southern Apparition for Comet T4 Lemmon". Universe Today. Retrieved 29 July 2023.
- ^ C/2021 T4 ( Lemmon ) mag chart by Seiichi Yoshida