| Parameter |
Value |
| Designation |
P/2025 W4 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2025-10-04T11:24:31.605120Z |
| Orbit solution date (soln_date, UTC) |
2026-03-11T21:13:02Z |
| Obs used |
104 |
| NEO |
- |
| M1 |
17.300 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-11-23T12:20:09.600000Z |
| Discovery magnitude (MPC) |
20.65 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-12-01.0000000 |
| e |
0.21117858 |
| q (au) |
2.034369 |
| a (au) |
2.578999 |
| i (deg) |
1.298188 |
| Ω (om, deg) |
237.120950 |
| ω (w, deg) |
172.279158 |
| M (ma, deg) |
13.689301 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.654 |
| k |
0.916 |
| 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 |
10:53:18.22 |
+06:04:40.7 |
HIP 53362 |
25.74 |
| 2026-09-20 12:00 |
10:54:05.36 |
+05:59:49.7 |
HIP 53362 |
13.43 |
| 2026-09-21 00:00 |
10:54:52.44 |
+05:54:58.7 |
HIP 53362 |
4.45 |
| 2026-09-21 12:00 |
10:55:39.45 |
+05:50:07.7 |
HIP 53362 |
13.42 |
| 2026-09-22 00:00 |
10:56:26.41 |
+05:45:16.6 |
HIP 53513 |
9.49 |
| 2026-09-22 12:00 |
10:57:13.30 |
+05:40:25.6 |
HIP 53513 |
6.26 |
| 2026-09-23 00:00 |
10:58:00.14 |
+05:35:34.5 |
HIP 53513 |
17.53 |
| 2026-09-23 12:00 |
10:58:46.91 |
+05:30:43.4 |
HIP 53513 |
29.88 |
| 2026-09-24 00:00 |
10:59:33.63 |
+05:25:52.4 |
HIP 53856 |
23.14 |
| 2026-09-24 12:00 |
11:00:20.28 |
+05:21:01.3 |
HIP 53856 |
10.82 |
| 2026-09-25 00:00 |
11:01:06.87 |
+05:16:10.2 |
HIP 53856 |
3.93 |
| 2026-09-25 12:00 |
11:01:53.40 |
+05:11:19.2 |
HIP 53899 |
5.91 |
| 2026-09-26 00:00 |
11:02:39.87 |
+05:06:28.2 |
HIP 53899 |
14.39 |
| 2026-09-26 12:00 |
11:03:26.28 |
+05:01:37.2 |
HIP 54120 |
14.62 |
| 2026-09-27 00:00 |
11:04:12.63 |
+04:56:46.3 |
HIP 54120 |
7.03 |
| 2026-09-27 12:00 |
11:04:58.91 |
+04:51:55.4 |
HIP 54213 |
8.78 |
| 2026-09-28 00:00 |
11:05:45.14 |
+04:47:04.5 |
HIP 54213 |
6.46 |
| 2026-09-28 12:00 |
11:06:31.30 |
+04:42:13.7 |
HIP 54213 |
17.84 |
| 2026-09-29 00:00 |
11:07:17.41 |
+04:37:22.9 |
HIP 54440 |
18.50 |
| 2026-09-29 12:00 |
11:08:03.45 |
+04:32:32.3 |
HIP 54440 |
6.54 |
| 2026-09-30 00:00 |
11:08:49.43 |
+04:27:41.6 |
HIP 54440 |
7.29 |
| 2026-09-30 12:00 |
11:09:35.36 |
+04:22:51.1 |
HIP 54440 |
19.30 |
| 2026-10-01 00:00 |
11:10:21.21 |
+04:18:00.6 |
HIP 54440 |
31.63 |
| 2026-10-01 12:00 |
11:11:07.01 |
+04:13:10.2 |
HIP 54810 |
35.24 |
| 2026-10-02 00:00 |
11:11:52.75 |
+04:08:19.9 |
HIP 54810 |
28.80 |
| 2026-10-02 12:00 |
11:12:38.42 |
+04:03:29.7 |
HIP 54810 |
26.90 |
| 2026-10-03 00:00 |
11:13:24.04 |
+03:58:39.6 |
HIP 54886 |
23.42 |
| 2026-10-03 12:00 |
11:14:09.59 |
+03:53:49.6 |
HIP 54886 |
24.04 |
| 2026-10-04 00:00 |
11:14:55.08 |
+03:48:59.7 |
HIP 54853 |
28.56 |
| 2026-10-04 12:00 |
11:15:40.50 |
+03:44:09.9 |
HIP 55102 |
22.51 |
| 2026-10-05 00:00 |
11:16:25.87 |
+03:39:20.3 |
HIP 55102 |
19.22 |
| 2026-10-05 12:00 |
11:17:11.16 |
+03:34:30.8 |
HIP 55102 |
23.12 |
| 2026-10-06 00:00 |
11:17:56.40 |
+03:29:41.5 |
HIP 55231 |
23.71 |
| 2026-10-06 12:00 |
11:18:41.57 |
+03:24:52.3 |
HIP 55231 |
16.57 |
| 2026-10-07 00:00 |
11:19:26.68 |
+03:20:03.3 |
HIP 55231 |
16.96 |
| 2026-10-07 12:00 |
11:20:11.72 |
+03:15:14.4 |
HIP 55324 |
23.05 |
| 2026-10-08 00:00 |
11:20:56.70 |
+03:10:25.7 |
HIP 55408 |
18.81 |
| 2026-10-08 12:00 |
11:21:41.61 |
+03:05:37.2 |
HIP 55408 |
19.23 |
| 2026-10-09 00:00 |
11:22:26.45 |
+03:00:48.9 |
HIP 55408 |
26.13 |
| 2026-10-09 12:00 |
11:23:11.23 |
+02:56:00.8 |
HIP 55408 |
35.94 |
| 2026-10-10 00:00 |
11:23:55.95 |
+02:51:12.9 |
HIP 55769 |
37.27 |
| 2026-10-10 12:00 |
11:24:40.59 |
+02:46:25.2 |
HIP 55846 |
34.38 |
| 2026-10-11 00:00 |
11:25:25.17 |
+02:41:37.8 |
HIP 55848 |
27.66 |