| Parameter |
Value |
| Designation |
C/2021 B3 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-03-10T21:53:20.584320Z |
| Orbit solution date (soln_date, UTC) |
2021-07-01T22:12:56Z |
| Obs used |
84 |
| NEO |
- |
| M1 |
13.900 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-01-22T05:58:17.184000Z |
| Discovery magnitude (MPC) |
19.00 R |
| Discovery observatory (MPC) |
C51 · WISE |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-02-16.0000000 |
| e |
0.93819965 |
| q (au) |
2.160159 |
| a (au) |
34.953837 |
| i (deg) |
119.489804 |
| Ω (om, deg) |
67.284845 |
| ω (w, deg) |
293.559147 |
| M (ma, deg) |
359.890724 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.234 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.234 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-03-26 00:00 |
22:42:00.32 |
+50:31:31.6 |
HIP 112133 |
16.95 |
| 2026-03-26 12:00 |
22:42:09.16 |
+50:32:37.5 |
HIP 112133 |
15.34 |
| 2026-03-27 00:00 |
22:42:17.96 |
+50:33:44.0 |
HIP 112133 |
13.75 |
| 2026-03-27 12:00 |
22:42:26.71 |
+50:34:51.1 |
HIP 112133 |
12.22 |
| 2026-03-28 00:00 |
22:42:35.42 |
+50:35:58.9 |
HIP 112133 |
10.75 |
| 2026-03-28 12:00 |
22:42:44.08 |
+50:37:07.3 |
HIP 112133 |
9.38 |
| 2026-03-29 00:00 |
22:42:52.70 |
+50:38:16.3 |
HIP 112133 |
8.16 |
| 2026-03-29 12:00 |
22:43:01.27 |
+50:39:26.0 |
HIP 112133 |
7.18 |
| 2026-03-30 00:00 |
22:43:09.80 |
+50:40:36.3 |
HIP 112133 |
6.52 |
| 2026-03-30 12:00 |
22:43:18.27 |
+50:41:47.2 |
HIP 112133 |
6.31 |
| 2026-03-31 00:00 |
22:43:26.70 |
+50:42:58.7 |
HIP 112133 |
6.58 |
| 2026-03-31 12:00 |
22:43:35.08 |
+50:44:10.8 |
HIP 112244 |
6.55 |
| 2026-04-01 00:00 |
22:43:43.41 |
+50:45:23.5 |
HIP 112244 |
4.76 |
| 2026-04-01 12:00 |
22:43:51.69 |
+50:46:36.8 |
HIP 112244 |
2.97 |
| 2026-04-02 00:00 |
22:43:59.92 |
+50:47:50.7 |
HIP 112244 |
1.18 |
| 2026-04-02 12:00 |
22:44:08.09 |
+50:49:05.1 |
HIP 112244 |
0.62 |
| 2026-04-03 00:00 |
22:44:16.22 |
+50:50:20.2 |
HIP 112244 |
2.41 |
| 2026-04-03 12:00 |
22:44:24.30 |
+50:51:35.9 |
HIP 112244 |
4.20 |
| 2026-04-04 00:00 |
22:44:32.32 |
+50:52:52.1 |
HIP 112244 |
5.99 |
| 2026-04-04 12:00 |
22:44:40.29 |
+50:54:08.8 |
HIP 112244 |
7.78 |
| 2026-04-05 00:00 |
22:44:48.20 |
+50:55:26.2 |
HIP 112244 |
9.58 |
| 2026-04-05 12:00 |
22:44:56.06 |
+50:56:44.1 |
HIP 112244 |
11.37 |
| 2026-04-06 00:00 |
22:45:03.87 |
+50:58:02.6 |
HIP 112244 |
13.17 |
| 2026-04-06 12:00 |
22:45:11.62 |
+50:59:21.6 |
HIP 112244 |
14.96 |
| 2026-04-07 00:00 |
22:45:19.31 |
+51:00:41.1 |
HIP 112244 |
16.76 |
| 2026-04-07 12:00 |
22:45:26.95 |
+51:02:01.3 |
HIP 112244 |
18.55 |
| 2026-04-08 00:00 |
22:45:34.53 |
+51:03:21.9 |
HIP 112244 |
20.35 |
| 2026-04-08 12:00 |
22:45:42.05 |
+51:04:43.1 |
HIP 112555 |
20.58 |
| 2026-04-09 00:00 |
22:45:49.51 |
+51:06:04.8 |
HIP 112555 |
19.09 |
| 2026-04-09 12:00 |
22:45:56.91 |
+51:07:27.0 |
HIP 112555 |
17.67 |
| 2026-04-10 00:00 |
22:46:04.26 |
+51:08:49.7 |
HIP 112555 |
16.32 |
| 2026-04-10 12:00 |
22:46:11.54 |
+51:10:13.0 |
HIP 112555 |
15.08 |
| 2026-04-11 00:00 |
22:46:18.76 |
+51:11:36.8 |
HIP 112555 |
13.98 |
| 2026-04-11 12:00 |
22:46:25.92 |
+51:13:01.0 |
HIP 112555 |
13.04 |
| 2026-04-12 00:00 |
22:46:33.02 |
+51:14:25.8 |
HIP 112555 |
12.31 |
| 2026-04-12 12:00 |
22:46:40.06 |
+51:15:51.1 |
HIP 112555 |
11.82 |
| 2026-04-13 00:00 |
22:46:47.03 |
+51:17:16.8 |
HIP 112555 |
11.61 |
| 2026-04-13 12:00 |
22:46:53.94 |
+51:18:43.1 |
HIP 112555 |
11.69 |
| 2026-04-14 00:00 |
22:47:00.78 |
+51:20:09.8 |
HIP 112555 |
12.05 |
| 2026-04-14 12:00 |
22:47:07.56 |
+51:21:37.0 |
HIP 112555 |
12.67 |
| 2026-04-15 00:00 |
22:47:14.27 |
+51:23:04.6 |
HIP 112555 |
13.52 |
| 2026-04-15 12:00 |
22:47:20.91 |
+51:24:32.7 |
HIP 112555 |
14.55 |
| 2026-04-16 00:00 |
22:47:27.49 |
+51:26:01.3 |
HIP 112555 |
15.73 |