| 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 |
0.999 |
| 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) |
| 2026-05-12 00:00 |
02:35:13.85 |
+28:36:57.5 |
HIP 11977 |
9.69 |
| 2026-05-12 12:00 |
02:36:11.32 |
+28:41:46.1 |
HIP 11977 |
22.43 |
| 2026-05-13 00:00 |
02:37:08.84 |
+28:46:34.0 |
HIP 12295 |
16.91 |
| 2026-05-13 12:00 |
02:38:06.41 |
+28:51:21.0 |
HIP 12295 |
10.93 |
| 2026-05-14 00:00 |
02:39:04.04 |
+28:56:07.3 |
HIP 12295 |
17.81 |
| 2026-05-14 12:00 |
02:40:01.72 |
+29:00:52.9 |
HIP 12295 |
29.64 |
| 2026-05-15 00:00 |
02:40:59.44 |
+29:05:37.6 |
HIP 12295 |
42.47 |
| 2026-05-15 12:00 |
02:41:57.22 |
+29:10:21.6 |
HIP 12808 |
38.83 |
| 2026-05-16 00:00 |
02:42:55.05 |
+29:15:04.7 |
HIP 12808 |
25.47 |
| 2026-05-16 12:00 |
02:43:52.93 |
+29:19:47.1 |
HIP 12808 |
12.36 |
| 2026-05-17 00:00 |
02:44:50.85 |
+29:24:28.7 |
HIP 12808 |
4.38 |
| 2026-05-17 12:00 |
02:45:48.82 |
+29:29:09.4 |
HIP 12808 |
15.75 |
| 2026-05-18 00:00 |
02:46:46.85 |
+29:33:49.3 |
HIP 13047 |
13.19 |
| 2026-05-18 12:00 |
02:47:44.91 |
+29:38:28.4 |
HIP 13047 |
2.63 |
| 2026-05-19 00:00 |
02:48:43.03 |
+29:43:06.6 |
HIP 13047 |
14.19 |
| 2026-05-19 12:00 |
02:49:41.19 |
+29:47:44.0 |
HIP 13047 |
27.52 |
| 2026-05-20 00:00 |
02:50:39.40 |
+29:52:20.6 |
HIP 13291 |
25.44 |
| 2026-05-20 12:00 |
02:51:37.65 |
+29:56:56.3 |
HIP 13374 |
15.78 |
| 2026-05-21 00:00 |
02:52:35.95 |
+30:01:31.1 |
HIP 13395 |
9.78 |
| 2026-05-21 12:00 |
02:53:34.29 |
+30:06:05.0 |
HIP 13395 |
16.13 |
| 2026-05-22 00:00 |
02:54:32.68 |
+30:10:38.1 |
HIP 13395 |
28.00 |
| 2026-05-22 12:00 |
02:55:31.11 |
+30:15:10.3 |
HIP 13395 |
40.84 |
| 2026-05-23 00:00 |
02:56:29.58 |
+30:19:41.6 |
HIP 13791 |
39.70 |
| 2026-05-23 12:00 |
02:57:28.10 |
+30:24:12.1 |
HIP 13969 |
33.87 |
| 2026-05-24 00:00 |
02:58:26.66 |
+30:28:41.6 |
HIP 13969 |
20.48 |
| 2026-05-24 12:00 |
02:59:25.26 |
+30:33:10.2 |
HIP 13969 |
7.13 |
| 2026-05-25 00:00 |
03:00:23.90 |
+30:37:37.9 |
HIP 14018 |
3.53 |
| 2026-05-25 12:00 |
03:01:22.59 |
+30:42:04.7 |
HIP 14018 |
14.36 |
| 2026-05-26 00:00 |
03:02:21.31 |
+30:46:30.6 |
HIP 14245 |
23.51 |
| 2026-05-26 12:00 |
03:03:20.08 |
+30:50:55.6 |
HIP 14245 |
20.82 |
| 2026-05-27 00:00 |
03:04:18.89 |
+30:55:19.6 |
HIP 14340 |
10.53 |
| 2026-05-27 12:00 |
03:05:17.74 |
+30:59:42.7 |
HIP 14340 |
5.43 |
| 2026-05-28 00:00 |
03:06:16.64 |
+31:04:04.9 |
HIP 14340 |
17.45 |
| 2026-05-28 12:00 |
03:07:15.57 |
+31:08:26.2 |
HIP 14340 |
30.59 |
| 2026-05-29 00:00 |
03:08:14.54 |
+31:12:46.4 |
HIP 14340 |
43.84 |
| 2026-05-29 12:00 |
03:09:13.55 |
+31:17:05.8 |
HIP 14840 |
31.39 |
| 2026-05-30 00:00 |
03:10:12.60 |
+31:21:24.2 |
HIP 14840 |
19.66 |
| 2026-05-30 12:00 |
03:11:11.69 |
+31:25:41.6 |
HIP 14840 |
11.97 |
| 2026-05-31 00:00 |
03:12:10.82 |
+31:29:58.1 |
HIP 14840 |
15.97 |
| 2026-05-31 12:00 |
03:13:09.99 |
+31:34:13.6 |
HIP 14840 |
26.86 |
| 2026-06-01 00:00 |
03:14:09.20 |
+31:38:28.2 |
HIP 15226 |
32.17 |
| 2026-06-01 12:00 |
03:15:08.44 |
+31:42:41.7 |
HIP 15226 |
19.50 |
| 2026-06-02 00:00 |
03:16:07.73 |
+31:46:54.3 |
HIP 15226 |
8.89 |