P/2021 A5 (PANSTARRS)
| 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) |
| 2026-02-03 00:00 |
23:47:18.27 |
+11:17:53.6 |
HIP 117356 |
9.16 |
| 2026-02-03 12:00 |
23:48:02.53 |
+11:22:52.5 |
HIP 117356 |
5.14 |
| 2026-02-04 00:00 |
23:48:46.89 |
+11:27:52.1 |
HIP 117356 |
15.96 |
| 2026-02-04 12:00 |
23:49:31.34 |
+11:32:52.4 |
HIP 117506 |
22.60 |
| 2026-02-05 00:00 |
23:50:15.88 |
+11:37:53.3 |
HIP 117506 |
28.60 |
| 2026-02-05 12:00 |
23:51:00.51 |
+11:42:55.0 |
HIP 117764 |
31.54 |
| 2026-02-06 00:00 |
23:51:45.23 |
+11:47:57.2 |
HIP 117764 |
19.49 |
| 2026-02-06 12:00 |
23:52:30.05 |
+11:53:00.2 |
HIP 117764 |
7.44 |
| 2026-02-07 00:00 |
23:53:14.95 |
+11:58:03.8 |
HIP 117768 |
4.50 |
| 2026-02-07 12:00 |
23:53:59.95 |
+12:03:08.0 |
HIP 117839 |
3.21 |
| 2026-02-08 00:00 |
23:54:45.03 |
+12:08:12.8 |
HIP 117839 |
14.46 |
| 2026-02-08 12:00 |
23:55:30.21 |
+12:13:18.3 |
HIP 117839 |
26.52 |
| 2026-02-09 00:00 |
23:56:15.47 |
+12:18:24.5 |
HIP 118047 |
31.44 |
| 2026-02-09 12:00 |
23:57:00.83 |
+12:23:31.2 |
HIP 118047 |
26.17 |
| 2026-02-10 00:00 |
23:57:46.27 |
+12:28:38.5 |
HIP 118047 |
26.05 |
| 2026-02-10 12:00 |
23:58:31.80 |
+12:33:46.5 |
HIP 118047 |
31.17 |
| 2026-02-11 00:00 |
23:59:17.42 |
+12:38:55.0 |
HIP 36 |
28.19 |
| 2026-02-11 12:00 |
00:00:03.12 |
+12:44:04.2 |
HIP 153 |
28.01 |
| 2026-02-12 00:00 |
00:00:48.91 |
+12:49:13.9 |
HIP 153 |
19.20 |
| 2026-02-12 12:00 |
00:01:34.79 |
+12:54:24.2 |
HIP 153 |
15.99 |
| 2026-02-13 00:00 |
00:02:20.76 |
+12:59:35.1 |
HIP 153 |
21.15 |
| 2026-02-13 12:00 |
00:03:06.81 |
+13:04:46.5 |
HIP 298 |
19.21 |
| 2026-02-14 00:00 |
00:03:52.94 |
+13:09:58.5 |
HIP 298 |
12.21 |
| 2026-02-14 12:00 |
00:04:39.16 |
+13:15:11.0 |
HIP 298 |
15.35 |
| 2026-02-15 00:00 |
00:05:25.46 |
+13:20:24.1 |
HIP 476 |
5.24 |
| 2026-02-15 12:00 |
00:06:11.85 |
+13:25:37.6 |
HIP 476 |
7.51 |
| 2026-02-16 00:00 |
00:06:58.32 |
+13:30:51.8 |
HIP 476 |
19.88 |
| 2026-02-16 12:00 |
00:07:44.87 |
+13:36:06.4 |
HIP 476 |
32.33 |
| 2026-02-17 00:00 |
00:08:31.50 |
+13:41:21.6 |
HIP 704 |
27.39 |
| 2026-02-17 12:00 |
00:09:18.22 |
+13:46:37.2 |
HIP 854 |
20.25 |
| 2026-02-18 00:00 |
00:10:05.02 |
+13:51:53.3 |
HIP 896 |
15.80 |
| 2026-02-18 12:00 |
00:10:51.90 |
+13:57:10.0 |
HIP 896 |
12.47 |
| 2026-02-19 00:00 |
00:11:38.86 |
+14:02:27.0 |
HIP 896 |
19.40 |
| 2026-02-19 12:00 |
00:12:25.89 |
+14:07:44.6 |
HIP 999 |
26.10 |
| 2026-02-20 00:00 |
00:13:13.01 |
+14:13:02.6 |
HIP 999 |
23.23 |
| 2026-02-20 12:00 |
00:14:00.21 |
+14:18:21.1 |
HIP 999 |
26.74 |
| 2026-02-21 00:00 |
00:14:47.48 |
+14:23:40.0 |
HIP 1277 |
26.03 |
| 2026-02-21 12:00 |
00:15:34.83 |
+14:28:59.3 |
HIP 1277 |
14.97 |
| 2026-02-22 00:00 |
00:16:22.26 |
+14:34:19.0 |
HIP 1277 |
9.49 |
| 2026-02-22 12:00 |
00:17:09.77 |
+14:39:39.2 |
HIP 1277 |
16.62 |
| 2026-02-23 00:00 |
00:17:57.35 |
+14:44:59.8 |
HIP 1528 |
23.32 |
| 2026-02-23 12:00 |
00:18:45.00 |
+14:50:20.7 |
HIP 1528 |
12.55 |
| 2026-02-24 00:00 |
00:19:32.74 |
+14:55:42.0 |
HIP 1528 |
9.69 |