| Parameter |
Value |
| Designation |
C/2021 B2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-05-04T06:39:22.443840Z |
| Orbit solution date (soln_date, UTC) |
2022-06-07T21:45:07Z |
| Obs used |
93 |
| NEO |
- |
| M1 |
12.200 |
| K1 |
12.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-01-17T05:33:50.803200Z |
| Discovery magnitude (MPC) |
19.96 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-04-03.0000000 |
| e |
0.99252519 |
| q (au) |
2.513062 |
| a (au) |
336.204150 |
| i (deg) |
38.094193 |
| Ω (om, deg) |
120.555561 |
| ω (w, deg) |
334.974070 |
| M (ma, deg) |
359.994999 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.993 + 5.531\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.993 |
| n |
5.531 |
| gf |
0.921 |
| gb |
-0.787 |
| k |
0.997 |
| δ90 |
6.451 |
| 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 |
16:02:07.58 |
+18:25:45.7 |
HIP 78570 |
20.20 |
| 2026-03-26 12:00 |
16:02:03.92 |
+18:26:56.2 |
HIP 78570 |
21.61 |
| 2026-03-27 00:00 |
16:02:00.19 |
+18:28:06.5 |
HIP 78570 |
23.03 |
| 2026-03-27 12:00 |
16:01:56.39 |
+18:29:16.6 |
HIP 78570 |
24.45 |
| 2026-03-28 00:00 |
16:01:52.52 |
+18:30:26.4 |
HIP 78570 |
25.89 |
| 2026-03-28 12:00 |
16:01:48.59 |
+18:31:36.0 |
HIP 78570 |
27.33 |
| 2026-03-29 00:00 |
16:01:44.59 |
+18:32:45.3 |
HIP 78570 |
28.78 |
| 2026-03-29 12:00 |
16:01:40.53 |
+18:33:54.4 |
HIP 78570 |
30.24 |
| 2026-03-30 00:00 |
16:01:36.40 |
+18:35:03.2 |
HIP 78570 |
31.71 |
| 2026-03-30 12:00 |
16:01:32.21 |
+18:36:11.7 |
HIP 78570 |
33.18 |
| 2026-03-31 00:00 |
16:01:27.95 |
+18:37:19.9 |
HIP 78570 |
34.66 |
| 2026-03-31 12:00 |
16:01:23.63 |
+18:38:27.9 |
HIP 78570 |
36.14 |
| 2026-04-01 00:00 |
16:01:19.24 |
+18:39:35.5 |
HIP 78570 |
37.63 |
| 2026-04-01 12:00 |
16:01:14.80 |
+18:40:42.9 |
HIP 78283 |
37.96 |
| 2026-04-02 00:00 |
16:01:10.29 |
+18:41:49.9 |
HIP 78283 |
37.73 |
| 2026-04-02 12:00 |
16:01:05.72 |
+18:42:56.7 |
HIP 78283 |
37.54 |
| 2026-04-03 00:00 |
16:01:01.08 |
+18:44:03.1 |
HIP 78283 |
37.40 |
| 2026-04-03 12:00 |
16:00:56.39 |
+18:45:09.2 |
HIP 78283 |
37.31 |
| 2026-04-04 00:00 |
16:00:51.63 |
+18:46:14.9 |
HIP 78283 |
37.28 |
| 2026-04-04 12:00 |
16:00:46.82 |
+18:47:20.3 |
HIP 78283 |
37.29 |
| 2026-04-05 00:00 |
16:00:41.94 |
+18:48:25.4 |
HIP 78283 |
37.36 |
| 2026-04-05 12:00 |
16:00:37.01 |
+18:49:30.1 |
HIP 78283 |
37.49 |
| 2026-04-06 00:00 |
16:00:32.01 |
+18:50:34.5 |
HIP 78283 |
37.67 |
| 2026-04-06 12:00 |
16:00:26.96 |
+18:51:38.5 |
HIP 78283 |
37.90 |
| 2026-04-07 00:00 |
16:00:21.85 |
+18:52:42.1 |
HIP 78283 |
38.19 |
| 2026-04-07 12:00 |
16:00:16.68 |
+18:53:45.3 |
HIP 78283 |
38.52 |
| 2026-04-08 00:00 |
16:00:11.46 |
+18:54:48.2 |
HIP 78283 |
38.92 |
| 2026-04-08 12:00 |
16:00:06.18 |
+18:55:50.7 |
HIP 78283 |
39.36 |
| 2026-04-09 00:00 |
16:00:00.84 |
+18:56:52.8 |
HIP 78283 |
39.86 |
| 2026-04-09 12:00 |
15:59:55.44 |
+18:57:54.4 |
HIP 78178 |
39.61 |
| 2026-04-10 00:00 |
15:59:50.00 |
+18:58:55.7 |
HIP 78178 |
37.97 |
| 2026-04-10 12:00 |
15:59:44.49 |
+18:59:56.6 |
HIP 78178 |
36.32 |
| 2026-04-11 00:00 |
15:59:38.94 |
+19:00:57.0 |
HIP 78178 |
34.67 |
| 2026-04-11 12:00 |
15:59:33.33 |
+19:01:57.0 |
HIP 78178 |
33.01 |
| 2026-04-12 00:00 |
15:59:27.66 |
+19:02:56.6 |
HIP 78178 |
31.34 |
| 2026-04-12 12:00 |
15:59:21.95 |
+19:03:55.7 |
HIP 78178 |
29.67 |
| 2026-04-13 00:00 |
15:59:16.18 |
+19:04:54.4 |
HIP 78178 |
28.00 |
| 2026-04-13 12:00 |
15:59:10.36 |
+19:05:52.6 |
HIP 78178 |
26.33 |
| 2026-04-14 00:00 |
15:59:04.49 |
+19:06:50.4 |
HIP 78178 |
24.65 |
| 2026-04-14 12:00 |
15:58:58.57 |
+19:07:47.7 |
HIP 78178 |
22.97 |
| 2026-04-15 00:00 |
15:58:52.60 |
+19:08:44.5 |
HIP 78178 |
21.28 |
| 2026-04-15 12:00 |
15:58:46.58 |
+19:09:40.9 |
HIP 78178 |
19.60 |
| 2026-04-16 00:00 |
15:58:40.51 |
+19:10:36.7 |
HIP 78178 |
17.92 |