C/2021 L3 (Borisov)

Metadata

Parameter Value
Designation C/2021 L3 (Borisov)
Type C
Perihelion (tp_cal, UTC) 2022-02-13T15:37:30.763200Z
Orbit solution date (soln_date, UTC) 2024-04-20T20:42:18Z
Obs used 215
NEO -
M1 9.500
K1 6.000
PC 0.030
Discovery observation (MPC, UTC) 2021-06-08T21:44:52.224000Z
Discovery magnitude (MPC) 20.20 R
Discovery observatory (MPC) L51 · MARGO, Nauchnyi
Osculating Elements
Parameter Value
Epoch (epoch_cal, TDB) 2022-03-04.0000000
e 1.00141430
q (au) 8.457762
a (au) -5980.195992
i (deg) 78.580039
Ω (om, deg) 344.969335
ω (w, deg) 91.593885
M (ma, deg) 0.000039

Magnitude

C/2021 L3 (Borisov) · Magnitude (Full range)

Scatter + Global Linear

$$ M_a = (9.235 + 2.109\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter Value
H0 9.235
n 2.109
gf 0.990
gb -0.789
k 1.000
δ90 10.000
Parameter Symbol Range Description
Absolute magnitude at 1 AU from Sun and Earth H0 -5 to 20 Intrinsic brightness of the comet
Photometric slope parameter n 2 to 6 Rate of brightness change with heliocentric distance
Forward scattering asymmetry factor gf 0.8 to 1 Degree of forward scattering
Backward scattering asymmetry factor gb -1 to -0.5 Degree of backward scattering
Partitioning coefficient k 0.8 to 1 Ratio between forward/backward scattering contributions
Dust-to-gas brightness ratio δ90 1 to 10 Relative contribution of dust scattering to gas emission

Reference: EPSC-DPS2025-160

Ephemeris

Date/Time (UTC) RA (J2000) Dec (J2000) Nearest HIP Dist from HIP (arcmin)
2026-05-12 00:00 11:04:56.30 +28:49:22.0 HIP 54208 11.66
2026-05-12 12:00 11:04:51.49 +28:48:01.3 HIP 54208 13.37
2026-05-13 00:00 11:04:46.76 +28:46:40.2 HIP 54132 14.53
2026-05-13 12:00 11:04:42.13 +28:45:18.5 HIP 54132 12.96
2026-05-14 00:00 11:04:37.58 +28:43:56.4 HIP 54132 11.43
2026-05-14 12:00 11:04:33.13 +28:42:33.8 HIP 54132 9.95
2026-05-15 00:00 11:04:28.76 +28:41:10.8 HIP 54132 8.53
2026-05-15 12:00 11:04:24.49 +28:39:47.3 HIP 54132 7.21
2026-05-16 00:00 11:04:20.30 +28:38:23.3 HIP 54132 6.07
2026-05-16 12:00 11:04:16.21 +28:36:58.8 HIP 54132 5.20
2026-05-17 00:00 11:04:12.21 +28:35:33.9 HIP 54132 4.76
2026-05-17 12:00 11:04:08.30 +28:34:08.6 HIP 54132 4.86
2026-05-18 00:00 11:04:04.48 +28:32:42.8 HIP 54132 5.46
2026-05-18 12:00 11:04:00.75 +28:31:16.6 HIP 54132 6.43
2026-05-19 00:00 11:03:57.11 +28:29:49.9 HIP 54132 7.62
2026-05-19 12:00 11:03:53.56 +28:28:22.8 HIP 54132 8.95
2026-05-20 00:00 11:03:50.10 +28:26:55.3 HIP 54132 10.36
2026-05-20 12:00 11:03:46.73 +28:25:27.4 HIP 54132 11.81
2026-05-21 00:00 11:03:43.45 +28:23:59.1 HIP 54132 13.30
2026-05-21 12:00 11:03:40.26 +28:22:30.3 HIP 54132 14.81
2026-05-22 00:00 11:03:37.16 +28:21:01.2 HIP 54132 16.34
2026-05-22 12:00 11:03:34.15 +28:19:31.6 HIP 54132 17.88
2026-05-23 00:00 11:03:31.24 +28:18:01.7 HIP 54132 19.42
2026-05-23 12:00 11:03:28.41 +28:16:31.4 HIP 54132 20.97
2026-05-24 00:00 11:03:25.66 +28:15:00.7 HIP 54132 22.53
2026-05-24 12:00 11:03:23.01 +28:13:29.6 HIP 54132 24.08
2026-05-25 00:00 11:03:20.45 +28:11:58.1 HIP 53932 25.20
2026-05-25 12:00 11:03:17.98 +28:10:26.3 HIP 53932 23.68
2026-05-26 00:00 11:03:15.59 +28:08:54.1 HIP 53932 22.18
2026-05-26 12:00 11:03:13.29 +28:07:21.6 HIP 53932 20.70
2026-05-27 00:00 11:03:11.08 +28:05:48.7 HIP 53932 19.26
2026-05-27 12:00 11:03:08.96 +28:04:15.4 HIP 53932 17.86
2026-05-28 00:00 11:03:06.93 +28:02:41.8 HIP 53932 16.51
2026-05-28 12:00 11:03:04.98 +28:01:07.9 HIP 53932 15.23
2026-05-29 00:00 11:03:03.12 +27:59:33.6 HIP 53932 14.03
2026-05-29 12:00 11:03:01.35 +27:57:59.0 HIP 53932 12.94
2026-05-30 00:00 11:02:59.66 +27:56:24.1 HIP 53932 11.99
2026-05-30 12:00 11:02:58.07 +27:54:48.8 HIP 53932 11.21
2026-05-31 00:00 11:02:56.55 +27:53:13.2 HIP 53932 10.65
2026-05-31 12:00 11:02:55.13 +27:51:37.3 HIP 53932 10.33
2026-06-01 00:00 11:02:53.79 +27:50:01.1 HIP 53932 10.28
2026-06-01 12:00 11:02:52.53 +27:48:24.6 HIP 53932 10.51
2026-06-02 00:00 11:02:51.36 +27:46:47.8 HIP 53932 11.00