| Parameter |
Value |
| Designation |
P/2021 A5 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-11-13T00:03:53.236800Z |
| Orbit solution date (soln_date, UTC) |
2025-01-14T17:42:18Z |
| Obs used |
47 |
| NEO |
- |
| M1 |
15.000 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-01-06T07:09:10.742400Z |
| Discovery magnitude (MPC) |
21.24 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-01-05.0000000 |
| e |
0.14092491 |
| q (au) |
2.622101 |
| a (au) |
3.052238 |
| i (deg) |
18.186098 |
| Ω (om, deg) |
328.718645 |
| ω (w, deg) |
61.512717 |
| M (ma, deg) |
9.795583 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.273 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.273 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.501 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
06:42:45.30 |
+40:26:21.2 |
HIP 32275 |
20.69 |
| 2026-09-20 12:00 |
06:43:28.25 |
+40:27:28.2 |
HIP 32275 |
13.63 |
| 2026-09-21 00:00 |
06:44:10.95 |
+40:28:35.3 |
HIP 32275 |
8.89 |
| 2026-09-21 12:00 |
06:44:53.40 |
+40:29:42.4 |
HIP 32277 |
10.03 |
| 2026-09-22 00:00 |
06:45:35.60 |
+40:30:49.5 |
HIP 32277 |
15.88 |
| 2026-09-22 12:00 |
06:46:17.55 |
+40:31:56.7 |
HIP 32486 |
18.51 |
| 2026-09-23 00:00 |
06:46:59.23 |
+40:33:03.8 |
HIP 32486 |
18.92 |
| 2026-09-23 12:00 |
06:47:40.66 |
+40:34:11.1 |
HIP 32486 |
22.37 |
| 2026-09-24 00:00 |
06:48:21.83 |
+40:35:18.4 |
HIP 32626 |
22.45 |
| 2026-09-24 12:00 |
06:49:02.73 |
+40:36:25.8 |
HIP 32626 |
22.67 |
| 2026-09-25 00:00 |
06:49:43.37 |
+40:37:33.3 |
HIP 32892 |
18.54 |
| 2026-09-25 12:00 |
06:50:23.74 |
+40:38:40.9 |
HIP 32892 |
12.80 |
| 2026-09-26 00:00 |
06:51:03.84 |
+40:39:48.6 |
HIP 32892 |
10.21 |
| 2026-09-26 12:00 |
06:51:43.67 |
+40:40:56.5 |
HIP 32916 |
11.42 |
| 2026-09-27 00:00 |
06:52:23.22 |
+40:42:04.5 |
HIP 32916 |
14.14 |
| 2026-09-27 12:00 |
06:53:02.50 |
+40:43:12.7 |
HIP 33159 |
16.54 |
| 2026-09-28 00:00 |
06:53:41.50 |
+40:44:21.0 |
HIP 33159 |
10.67 |
| 2026-09-28 12:00 |
06:54:20.21 |
+40:45:29.5 |
HIP 33159 |
8.10 |
| 2026-09-29 00:00 |
06:54:58.64 |
+40:46:38.2 |
HIP 33159 |
11.24 |
| 2026-09-29 12:00 |
06:55:36.79 |
+40:47:47.1 |
HIP 33159 |
17.13 |
| 2026-09-30 00:00 |
06:56:14.64 |
+40:48:56.2 |
HIP 33355 |
16.72 |
| 2026-09-30 12:00 |
06:56:52.21 |
+40:50:05.6 |
HIP 33494 |
9.65 |
| 2026-10-01 00:00 |
06:57:29.47 |
+40:51:15.2 |
HIP 33494 |
3.00 |
| 2026-10-01 12:00 |
06:58:06.44 |
+40:52:25.1 |
HIP 33494 |
5.15 |
| 2026-10-02 00:00 |
06:58:43.11 |
+40:53:35.2 |
HIP 33494 |
11.96 |
| 2026-10-02 12:00 |
06:59:19.48 |
+40:54:45.7 |
HIP 33494 |
18.88 |
| 2026-10-03 00:00 |
06:59:55.54 |
+40:55:56.4 |
HIP 33783 |
23.28 |
| 2026-10-03 12:00 |
07:00:31.29 |
+40:57:07.4 |
HIP 33783 |
19.78 |
| 2026-10-04 00:00 |
07:01:06.72 |
+40:58:18.7 |
HIP 33783 |
18.26 |
| 2026-10-04 12:00 |
07:01:41.85 |
+40:59:30.4 |
HIP 33783 |
19.14 |
| 2026-10-05 00:00 |
07:02:16.65 |
+41:00:42.4 |
HIP 33783 |
22.08 |
| 2026-10-05 12:00 |
07:02:51.13 |
+41:01:54.8 |
HIP 33783 |
26.35 |
| 2026-10-06 00:00 |
07:03:25.29 |
+41:03:07.5 |
HIP 34068 |
28.88 |
| 2026-10-06 12:00 |
07:03:59.12 |
+41:04:20.6 |
HIP 34068 |
29.41 |
| 2026-10-07 00:00 |
07:04:32.62 |
+41:05:34.1 |
HIP 34315 |
29.21 |
| 2026-10-07 12:00 |
07:05:05.78 |
+41:06:47.9 |
HIP 34315 |
23.13 |
| 2026-10-08 00:00 |
07:05:38.61 |
+41:08:02.2 |
HIP 34315 |
17.32 |
| 2026-10-08 12:00 |
07:06:11.10 |
+41:09:16.9 |
HIP 34315 |
12.03 |
| 2026-10-09 00:00 |
07:06:43.25 |
+41:10:32.0 |
HIP 34315 |
8.22 |
| 2026-10-09 12:00 |
07:07:15.05 |
+41:11:47.5 |
HIP 34315 |
8.11 |
| 2026-10-10 00:00 |
07:07:46.50 |
+41:13:03.4 |
HIP 34403 |
3.23 |
| 2026-10-10 12:00 |
07:08:17.60 |
+41:14:19.8 |
HIP 34403 |
3.93 |
| 2026-10-11 00:00 |
07:08:48.35 |
+41:15:36.7 |
HIP 34403 |
9.53 |