| Parameter |
Value |
| Designation |
81P/Wild 2 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-12-15T18:49:47.694720Z |
| Orbit solution date (soln_date, UTC) |
2024-09-12T12:06:16Z |
| Obs used |
2795 |
| NEO |
- |
| M1 |
9.800 |
| K1 |
12.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-11-21.0000000 |
| e |
0.53739891 |
| q (au) |
1.595856 |
| a (au) |
3.449746 |
| i (deg) |
3.237004 |
| Ω (om, deg) |
136.110221 |
| ω (w, deg) |
41.725231 |
| M (ma, deg) |
187.596681 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.658 + 5.323\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.658 |
| n |
5.323 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.894 |
| δ90 |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2020-09-17 |
2022-12-15 |
+5.7911 |
-3.099 |
| 2022-12-15 |
2023-03-16 |
+32.4001 |
-7.929 |
| 2023-03-16 |
2024-09-07 |
-2.8049 |
+1.007 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
00:48:21.32 |
+01:44:16.5 |
HIP 3655 |
26.17 |
| 2026-09-20 12:00 |
00:48:04.45 |
+01:42:18.9 |
HIP 3655 |
21.53 |
| 2026-09-21 00:00 |
00:47:47.51 |
+01:40:20.9 |
HIP 3655 |
16.86 |
| 2026-09-21 12:00 |
00:47:30.49 |
+01:38:22.7 |
HIP 3655 |
12.18 |
| 2026-09-22 00:00 |
00:47:13.40 |
+01:36:24.2 |
HIP 3655 |
7.49 |
| 2026-09-22 12:00 |
00:46:56.23 |
+01:34:25.4 |
HIP 3655 |
2.82 |
| 2026-09-23 00:00 |
00:46:39.00 |
+01:32:26.4 |
HIP 3655 |
2.13 |
| 2026-09-23 12:00 |
00:46:21.71 |
+01:30:27.1 |
HIP 3655 |
6.81 |
| 2026-09-24 00:00 |
00:46:04.35 |
+01:28:27.7 |
HIP 3655 |
11.56 |
| 2026-09-24 12:00 |
00:45:46.93 |
+01:26:28.0 |
HIP 3655 |
16.35 |
| 2026-09-25 00:00 |
00:45:29.45 |
+01:24:28.2 |
HIP 3655 |
21.15 |
| 2026-09-25 12:00 |
00:45:11.92 |
+01:22:28.2 |
HIP 3535 |
24.81 |
| 2026-09-26 00:00 |
00:44:54.34 |
+01:20:28.1 |
HIP 3535 |
26.88 |
| 2026-09-26 12:00 |
00:44:36.71 |
+01:18:27.9 |
HIP 3535 |
29.60 |
| 2026-09-27 00:00 |
00:44:19.03 |
+01:16:27.6 |
HIP 3535 |
32.82 |
| 2026-09-27 12:00 |
00:44:01.30 |
+01:14:27.2 |
HIP 3302 |
30.55 |
| 2026-09-28 00:00 |
00:43:43.54 |
+01:12:26.7 |
HIP 3302 |
25.69 |
| 2026-09-28 12:00 |
00:43:25.73 |
+01:10:26.1 |
HIP 3302 |
20.83 |
| 2026-09-29 00:00 |
00:43:07.89 |
+01:08:25.6 |
HIP 3302 |
15.97 |
| 2026-09-29 12:00 |
00:42:50.01 |
+01:06:25.0 |
HIP 3302 |
11.13 |
| 2026-09-30 00:00 |
00:42:32.11 |
+01:04:24.5 |
HIP 3302 |
6.37 |
| 2026-09-30 12:00 |
00:42:14.17 |
+01:02:23.9 |
HIP 3302 |
2.34 |
| 2026-10-01 00:00 |
00:41:56.21 |
+01:00:23.4 |
HIP 3296 |
1.83 |
| 2026-10-01 12:00 |
00:41:38.22 |
+00:58:23.0 |
HIP 3296 |
6.73 |
| 2026-10-02 00:00 |
00:41:20.22 |
+00:56:22.6 |
HIP 3296 |
11.66 |
| 2026-10-02 12:00 |
00:41:02.20 |
+00:54:22.3 |
HIP 3296 |
16.59 |
| 2026-10-03 00:00 |
00:40:44.16 |
+00:52:22.2 |
HIP 3296 |
21.52 |
| 2026-10-03 12:00 |
00:40:26.11 |
+00:50:22.2 |
HIP 3055 |
25.31 |
| 2026-10-04 00:00 |
00:40:08.05 |
+00:48:22.3 |
HIP 3055 |
21.68 |
| 2026-10-04 12:00 |
00:39:49.99 |
+00:46:22.6 |
HIP 3055 |
18.64 |
| 2026-10-05 00:00 |
00:39:31.92 |
+00:44:23.2 |
HIP 3055 |
16.54 |
| 2026-10-05 12:00 |
00:39:13.86 |
+00:42:23.9 |
HIP 3055 |
15.76 |
| 2026-10-06 00:00 |
00:38:55.79 |
+00:40:24.8 |
HIP 3055 |
16.49 |
| 2026-10-06 12:00 |
00:38:37.74 |
+00:38:26.1 |
HIP 2982 |
15.84 |
| 2026-10-07 00:00 |
00:38:19.69 |
+00:36:27.5 |
HIP 2982 |
11.65 |
| 2026-10-07 12:00 |
00:38:01.65 |
+00:34:29.3 |
HIP 2982 |
8.30 |
| 2026-10-08 00:00 |
00:37:43.63 |
+00:32:31.4 |
HIP 2982 |
7.12 |
| 2026-10-08 12:00 |
00:37:25.62 |
+00:30:33.9 |
HIP 2982 |
8.98 |
| 2026-10-09 00:00 |
00:37:07.64 |
+00:28:36.6 |
HIP 2982 |
12.60 |
| 2026-10-09 12:00 |
00:36:49.68 |
+00:26:39.8 |
HIP 2982 |
16.88 |
| 2026-10-10 00:00 |
00:36:31.75 |
+00:24:43.4 |
HIP 2982 |
21.41 |
| 2026-10-10 12:00 |
00:36:13.85 |
+00:22:47.3 |
HIP 2982 |
26.06 |
| 2026-10-11 00:00 |
00:35:55.98 |
+00:20:51.7 |
HIP 2982 |
30.77 |