| 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) |
| 2026-05-12 00:00 |
15:52:35.97 |
+19:45:49.1 |
HIP 77869 |
29.86 |
| 2026-05-12 12:00 |
15:52:28.36 |
+19:46:12.6 |
HIP 77723 |
29.26 |
| 2026-05-13 00:00 |
15:52:20.73 |
+19:46:35.4 |
HIP 77723 |
28.58 |
| 2026-05-13 12:00 |
15:52:13.10 |
+19:46:57.5 |
HIP 77723 |
28.02 |
| 2026-05-14 00:00 |
15:52:05.46 |
+19:47:18.9 |
HIP 77723 |
27.58 |
| 2026-05-14 12:00 |
15:51:57.81 |
+19:47:39.5 |
HIP 77723 |
27.27 |
| 2026-05-15 00:00 |
15:51:50.16 |
+19:47:59.5 |
HIP 77549 |
26.48 |
| 2026-05-15 12:00 |
15:51:42.50 |
+19:48:18.7 |
HIP 77549 |
24.82 |
| 2026-05-16 00:00 |
15:51:34.83 |
+19:48:37.2 |
HIP 77549 |
23.19 |
| 2026-05-16 12:00 |
15:51:27.17 |
+19:48:55.0 |
HIP 77549 |
21.57 |
| 2026-05-17 00:00 |
15:51:19.50 |
+19:49:12.0 |
HIP 77549 |
19.99 |
| 2026-05-17 12:00 |
15:51:11.82 |
+19:49:28.4 |
HIP 77549 |
18.45 |
| 2026-05-18 00:00 |
15:51:04.15 |
+19:49:44.0 |
HIP 77549 |
16.96 |
| 2026-05-18 12:00 |
15:50:56.47 |
+19:49:58.9 |
HIP 77549 |
15.54 |
| 2026-05-19 00:00 |
15:50:48.80 |
+19:50:13.0 |
HIP 77549 |
14.20 |
| 2026-05-19 12:00 |
15:50:41.12 |
+19:50:26.4 |
HIP 77549 |
12.97 |
| 2026-05-20 00:00 |
15:50:33.45 |
+19:50:39.1 |
HIP 77549 |
11.88 |
| 2026-05-20 12:00 |
15:50:25.78 |
+19:50:51.0 |
HIP 77549 |
10.98 |
| 2026-05-21 00:00 |
15:50:18.12 |
+19:51:02.3 |
HIP 77549 |
10.30 |
| 2026-05-21 12:00 |
15:50:10.46 |
+19:51:12.7 |
HIP 77549 |
9.91 |
| 2026-05-22 00:00 |
15:50:02.80 |
+19:51:22.5 |
HIP 77549 |
9.83 |
| 2026-05-22 12:00 |
15:49:55.15 |
+19:51:31.5 |
HIP 77549 |
10.06 |
| 2026-05-23 00:00 |
15:49:47.51 |
+19:51:39.8 |
HIP 77549 |
10.59 |
| 2026-05-23 12:00 |
15:49:39.87 |
+19:51:47.3 |
HIP 77549 |
11.37 |
| 2026-05-24 00:00 |
15:49:32.24 |
+19:51:54.1 |
HIP 77549 |
12.36 |
| 2026-05-24 12:00 |
15:49:24.62 |
+19:52:00.2 |
HIP 77549 |
13.50 |
| 2026-05-25 00:00 |
15:49:17.01 |
+19:52:05.5 |
HIP 77549 |
14.76 |
| 2026-05-25 12:00 |
15:49:09.41 |
+19:52:10.1 |
HIP 77549 |
16.12 |
| 2026-05-26 00:00 |
15:49:01.83 |
+19:52:14.0 |
HIP 77549 |
17.54 |
| 2026-05-26 12:00 |
15:48:54.25 |
+19:52:17.1 |
HIP 77549 |
19.01 |
| 2026-05-27 00:00 |
15:48:46.69 |
+19:52:19.5 |
HIP 77549 |
20.53 |
| 2026-05-27 12:00 |
15:48:39.14 |
+19:52:21.2 |
HIP 77549 |
22.07 |
| 2026-05-28 00:00 |
15:48:31.60 |
+19:52:22.1 |
HIP 77549 |
23.64 |
| 2026-05-28 12:00 |
15:48:24.08 |
+19:52:22.3 |
HIP 77549 |
25.23 |
| 2026-05-29 00:00 |
15:48:16.57 |
+19:52:21.8 |
HIP 77269 |
24.95 |
| 2026-05-29 12:00 |
15:48:09.08 |
+19:52:20.5 |
HIP 77269 |
23.24 |
| 2026-05-30 00:00 |
15:48:01.61 |
+19:52:18.5 |
HIP 77269 |
21.53 |
| 2026-05-30 12:00 |
15:47:54.15 |
+19:52:15.8 |
HIP 77269 |
19.84 |
| 2026-05-31 00:00 |
15:47:46.71 |
+19:52:12.3 |
HIP 77269 |
18.17 |
| 2026-05-31 12:00 |
15:47:39.29 |
+19:52:08.2 |
HIP 77269 |
16.52 |
| 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 |