C/2021 P1 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2021 P1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-06-01T16:41:49.732800Z |
| Orbit solution date (soln_date, UTC) |
2024-03-19T12:12:38Z |
| Obs used |
104 |
| NEO |
- |
| M1 |
12.700 |
| K1 |
7.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-08-04T13:25:21.792000Z |
| Discovery magnitude (MPC) |
21.20 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-09-13.0000000 |
| e |
1.00024450 |
| q (au) |
4.374954 |
| a (au) |
-17893.332037 |
| i (deg) |
51.622012 |
| Ω (om, deg) |
359.671523 |
| ω (w, deg) |
40.363907 |
| M (ma, deg) |
-0.000108 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.879 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.879 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.791 |
| k |
0.800 |
| 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) |
| 2026-02-03 00:00 |
11:26:30.29 |
+39:01:34.3 |
HIP 55819 |
22.62 |
| 2026-02-03 12:00 |
11:26:19.85 |
+39:02:35.5 |
HIP 55819 |
21.61 |
| 2026-02-04 00:00 |
11:26:09.33 |
+39:03:36.2 |
HIP 55819 |
20.80 |
| 2026-02-04 12:00 |
11:25:58.74 |
+39:04:36.4 |
HIP 55819 |
20.23 |
| 2026-02-05 00:00 |
11:25:48.07 |
+39:05:36.1 |
HIP 55819 |
19.92 |
| 2026-02-05 12:00 |
11:25:37.32 |
+39:06:35.2 |
HIP 55819 |
19.88 |
| 2026-02-06 00:00 |
11:25:26.50 |
+39:07:33.9 |
HIP 55819 |
20.12 |
| 2026-02-06 12:00 |
11:25:15.61 |
+39:08:32.0 |
HIP 55819 |
20.64 |
| 2026-02-07 00:00 |
11:25:04.64 |
+39:09:29.5 |
HIP 55819 |
21.42 |
| 2026-02-07 12:00 |
11:24:53.60 |
+39:10:26.5 |
HIP 55819 |
22.42 |
| 2026-02-08 00:00 |
11:24:42.49 |
+39:11:22.9 |
HIP 55819 |
23.63 |
| 2026-02-08 12:00 |
11:24:31.31 |
+39:12:18.7 |
HIP 55819 |
25.02 |
| 2026-02-09 00:00 |
11:24:20.07 |
+39:13:13.9 |
HIP 55819 |
26.56 |
| 2026-02-09 12:00 |
11:24:08.75 |
+39:14:08.5 |
HIP 55819 |
28.23 |
| 2026-02-10 00:00 |
11:23:57.37 |
+39:15:02.5 |
HIP 55819 |
30.01 |
| 2026-02-10 12:00 |
11:23:45.93 |
+39:15:55.9 |
HIP 55819 |
31.88 |
| 2026-02-11 00:00 |
11:23:34.42 |
+39:16:48.6 |
HIP 55447 |
32.93 |
| 2026-02-11 12:00 |
11:23:22.86 |
+39:17:40.7 |
HIP 55447 |
30.65 |
| 2026-02-12 00:00 |
11:23:11.23 |
+39:18:32.2 |
HIP 55447 |
28.39 |
| 2026-02-12 12:00 |
11:22:59.54 |
+39:19:22.9 |
HIP 55447 |
26.15 |
| 2026-02-13 00:00 |
11:22:47.79 |
+39:20:13.0 |
HIP 55447 |
23.94 |
| 2026-02-13 12:00 |
11:22:35.99 |
+39:21:02.5 |
HIP 55447 |
21.78 |
| 2026-02-14 00:00 |
11:22:24.13 |
+39:21:51.2 |
HIP 55447 |
19.69 |
| 2026-02-14 12:00 |
11:22:12.22 |
+39:22:39.2 |
HIP 55447 |
17.69 |
| 2026-02-15 00:00 |
11:22:00.25 |
+39:23:26.5 |
HIP 55447 |
15.81 |
| 2026-02-15 12:00 |
11:21:48.24 |
+39:24:13.1 |
HIP 55447 |
14.12 |
| 2026-02-16 00:00 |
11:21:36.17 |
+39:24:58.9 |
HIP 55447 |
12.68 |
| 2026-02-16 12:00 |
11:21:24.06 |
+39:25:44.0 |
HIP 55447 |
11.60 |
| 2026-02-17 00:00 |
11:21:11.89 |
+39:26:28.4 |
HIP 55447 |
10.99 |
| 2026-02-17 12:00 |
11:20:59.69 |
+39:27:12.0 |
HIP 55447 |
10.92 |
| 2026-02-18 00:00 |
11:20:47.44 |
+39:27:54.8 |
HIP 55447 |
11.41 |
| 2026-02-18 12:00 |
11:20:35.14 |
+39:28:36.8 |
HIP 55447 |
12.40 |
| 2026-02-19 00:00 |
11:20:22.81 |
+39:29:18.1 |
HIP 55447 |
13.78 |
| 2026-02-19 12:00 |
11:20:10.43 |
+39:29:58.6 |
HIP 55447 |
15.45 |
| 2026-02-20 00:00 |
11:19:58.02 |
+39:30:38.2 |
HIP 55447 |
17.32 |
| 2026-02-20 12:00 |
11:19:45.57 |
+39:31:17.1 |
HIP 55447 |
19.35 |
| 2026-02-21 00:00 |
11:19:33.08 |
+39:31:55.1 |
HIP 55447 |
21.48 |
| 2026-02-21 12:00 |
11:19:20.56 |
+39:32:32.3 |
HIP 55447 |
23.68 |
| 2026-02-22 00:00 |
11:19:08.01 |
+39:33:08.7 |
HIP 55447 |
25.95 |
| 2026-02-22 12:00 |
11:18:55.43 |
+39:33:44.2 |
HIP 55447 |
28.26 |
| 2026-02-23 00:00 |
11:18:42.82 |
+39:34:18.9 |
HIP 55103 |
27.54 |
| 2026-02-23 12:00 |
11:18:30.18 |
+39:34:52.8 |
HIP 55103 |
25.35 |
| 2026-02-24 00:00 |
11:18:17.52 |
+39:35:25.7 |
HIP 55103 |
23.23 |