| 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
$$
M_a = (10.993 + 5.530\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.993 |
| n |
5.530 |
| gf |
0.921 |
| gb |
-0.787 |
| k |
0.997 |
| δ90 |
6.444 |
| 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) |
| 2026-06-01 00:00 |
15:47:31.89 |
+19:52:03.2 |
HIP 77269 |
14.90 |
| 2026-06-01 12:00 |
15:47:24.51 |
+19:51:57.6 |
HIP 77269 |
13.33 |
| 2026-06-02 00:00 |
15:47:17.15 |
+19:51:51.2 |
HIP 77269 |
11.81 |
| 2026-06-02 12:00 |
15:47:09.81 |
+19:51:44.1 |
HIP 77269 |
10.36 |
| 2026-06-03 00:00 |
15:47:02.50 |
+19:51:36.3 |
HIP 77269 |
9.03 |
| 2026-06-03 12:00 |
15:46:55.20 |
+19:51:27.8 |
HIP 77269 |
7.87 |
| 2026-06-04 00:00 |
15:46:47.93 |
+19:51:18.5 |
HIP 77247 |
6.60 |
| 2026-06-04 12:00 |
15:46:40.69 |
+19:51:08.5 |
HIP 77247 |
5.27 |
| 2026-06-05 00:00 |
15:46:33.47 |
+19:50:57.8 |
HIP 77247 |
4.23 |
| 2026-06-05 12:00 |
15:46:26.27 |
+19:50:46.4 |
HIP 77247 |
3.74 |
| 2026-06-06 00:00 |
15:46:19.10 |
+19:50:34.2 |
HIP 77247 |
4.00 |
| 2026-06-06 12:00 |
15:46:11.96 |
+19:50:21.3 |
HIP 77247 |
4.88 |
| 2026-06-07 00:00 |
15:46:04.84 |
+19:50:07.7 |
HIP 77247 |
6.11 |
| 2026-06-07 12:00 |
15:45:57.75 |
+19:49:53.4 |
HIP 77247 |
7.53 |
| 2026-06-08 00:00 |
15:45:50.69 |
+19:49:38.4 |
HIP 77247 |
9.04 |
| 2026-06-08 12:00 |
15:45:43.66 |
+19:49:22.7 |
HIP 77247 |
10.60 |
| 2026-06-09 00:00 |
15:45:36.66 |
+19:49:06.2 |
HIP 77247 |
12.19 |
| 2026-06-09 12:00 |
15:45:29.69 |
+19:48:49.1 |
HIP 77247 |
13.79 |
| 2026-06-10 00:00 |
15:45:22.75 |
+19:48:31.2 |
HIP 77247 |
15.41 |
| 2026-06-10 12:00 |
15:45:15.85 |
+19:48:12.6 |
HIP 77247 |
17.03 |
| 2026-06-11 00:00 |
15:45:08.97 |
+19:47:53.3 |
HIP 77247 |
18.65 |
| 2026-06-11 12:00 |
15:45:02.13 |
+19:47:33.3 |
HIP 77247 |
20.28 |
| 2026-06-12 00:00 |
15:44:55.33 |
+19:47:12.7 |
HIP 77247 |
21.90 |
| 2026-06-12 12:00 |
15:44:48.55 |
+19:46:51.3 |
HIP 77247 |
23.53 |
| 2026-06-13 00:00 |
15:44:41.82 |
+19:46:29.2 |
HIP 77247 |
25.14 |
| 2026-06-13 12:00 |
15:44:35.11 |
+19:46:06.4 |
HIP 77247 |
26.76 |
| 2026-06-14 00:00 |
15:44:28.45 |
+19:45:42.9 |
HIP 77247 |
28.37 |
| 2026-06-14 12:00 |
15:44:21.82 |
+19:45:18.7 |
HIP 77247 |
29.98 |
| 2026-06-15 00:00 |
15:44:15.23 |
+19:44:53.8 |
HIP 77247 |
31.58 |
| 2026-06-15 12:00 |
15:44:08.68 |
+19:44:28.2 |
HIP 77247 |
33.18 |
| 2026-06-16 00:00 |
15:44:02.17 |
+19:44:02.0 |
HIP 77247 |
34.77 |
| 2026-06-16 12:00 |
15:43:55.70 |
+19:43:35.0 |
HIP 76852 |
33.73 |
| 2026-06-17 00:00 |
15:43:49.27 |
+19:43:07.4 |
HIP 76852 |
32.18 |
| 2026-06-17 12:00 |
15:43:42.88 |
+19:42:39.1 |
HIP 76852 |
30.65 |
| 2026-06-18 00:00 |
15:43:36.53 |
+19:42:10.2 |
HIP 76852 |
29.12 |
| 2026-06-18 12:00 |
15:43:30.22 |
+19:41:40.5 |
HIP 76852 |
27.61 |
| 2026-06-19 00:00 |
15:43:23.96 |
+19:41:10.2 |
HIP 76852 |
26.12 |
| 2026-06-19 12:00 |
15:43:17.74 |
+19:40:39.3 |
HIP 76852 |
24.64 |
| 2026-06-20 00:00 |
15:43:11.56 |
+19:40:07.6 |
HIP 76852 |
23.18 |
| 2026-06-20 12:00 |
15:43:05.43 |
+19:39:35.3 |
HIP 76852 |
21.75 |
| 2026-06-21 00:00 |
15:42:59.34 |
+19:39:02.4 |
HIP 76852 |
20.34 |
| 2026-06-21 12:00 |
15:42:53.30 |
+19:38:28.8 |
HIP 76852 |
18.96 |
| 2026-06-22 00:00 |
15:42:47.31 |
+19:37:54.6 |
HIP 76852 |
17.63 |