| 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) |
| 2026-06-01 00:00 |
00:47:43.46 |
+02:46:23.9 |
HIP 3722 |
7.90 |
| 2026-06-01 12:00 |
00:47:59.40 |
+02:47:51.1 |
HIP 3758 |
5.40 |
| 2026-06-02 00:00 |
00:48:15.26 |
+02:49:17.7 |
HIP 3758 |
5.54 |
| 2026-06-02 12:00 |
00:48:31.02 |
+02:50:43.5 |
HIP 3758 |
8.21 |
| 2026-06-03 00:00 |
00:48:46.69 |
+02:52:08.7 |
HIP 3758 |
11.77 |
| 2026-06-03 12:00 |
00:49:02.26 |
+02:53:33.1 |
HIP 3758 |
15.61 |
| 2026-06-04 00:00 |
00:49:17.74 |
+02:54:56.9 |
HIP 3758 |
19.54 |
| 2026-06-04 12:00 |
00:49:33.12 |
+02:56:19.9 |
HIP 3758 |
23.50 |
| 2026-06-05 00:00 |
00:49:48.40 |
+02:57:42.2 |
HIP 3973 |
23.06 |
| 2026-06-05 12:00 |
00:50:03.58 |
+02:59:03.8 |
HIP 3973 |
20.96 |
| 2026-06-06 00:00 |
00:50:18.67 |
+03:00:24.6 |
HIP 3973 |
19.49 |
| 2026-06-06 12:00 |
00:50:33.65 |
+03:01:44.7 |
HIP 3973 |
18.77 |
| 2026-06-07 00:00 |
00:50:48.54 |
+03:03:04.1 |
HIP 3973 |
18.87 |
| 2026-06-07 12:00 |
00:51:03.32 |
+03:04:22.7 |
HIP 3992 |
19.10 |
| 2026-06-08 00:00 |
00:51:18.00 |
+03:05:40.5 |
HIP 3992 |
17.43 |
| 2026-06-08 12:00 |
00:51:32.57 |
+03:06:57.7 |
HIP 3992 |
16.54 |
| 2026-06-09 00:00 |
00:51:47.05 |
+03:08:14.0 |
HIP 3992 |
16.52 |
| 2026-06-09 12:00 |
00:52:01.41 |
+03:09:29.6 |
HIP 3992 |
17.35 |
| 2026-06-10 00:00 |
00:52:15.68 |
+03:10:44.4 |
HIP 3992 |
18.92 |
| 2026-06-10 12:00 |
00:52:29.83 |
+03:11:58.5 |
HIP 4186 |
15.91 |
| 2026-06-11 00:00 |
00:52:43.88 |
+03:13:11.7 |
HIP 4186 |
12.21 |
| 2026-06-11 12:00 |
00:52:57.82 |
+03:14:24.2 |
HIP 4186 |
8.54 |
| 2026-06-12 00:00 |
00:53:11.64 |
+03:15:35.9 |
HIP 4186 |
4.94 |
| 2026-06-12 12:00 |
00:53:25.36 |
+03:16:46.7 |
HIP 4186 |
1.60 |
| 2026-06-13 00:00 |
00:53:38.97 |
+03:17:56.8 |
HIP 4186 |
2.61 |
| 2026-06-13 12:00 |
00:53:52.46 |
+03:19:06.1 |
HIP 4186 |
6.04 |
| 2026-06-14 00:00 |
00:54:05.84 |
+03:20:14.5 |
HIP 4186 |
9.54 |
| 2026-06-14 12:00 |
00:54:19.11 |
+03:21:22.2 |
HIP 4186 |
13.02 |
| 2026-06-15 00:00 |
00:54:32.26 |
+03:22:29.0 |
HIP 4186 |
16.48 |
| 2026-06-15 12:00 |
00:54:45.30 |
+03:23:35.0 |
HIP 4186 |
19.91 |
| 2026-06-16 00:00 |
00:54:58.22 |
+03:24:40.1 |
HIP 4370 |
22.21 |
| 2026-06-16 12:00 |
00:55:11.02 |
+03:25:44.4 |
HIP 4370 |
19.25 |
| 2026-06-17 00:00 |
00:55:23.70 |
+03:26:47.9 |
HIP 4370 |
16.47 |
| 2026-06-17 12:00 |
00:55:36.26 |
+03:27:50.6 |
HIP 4370 |
13.96 |
| 2026-06-18 00:00 |
00:55:48.71 |
+03:28:52.3 |
HIP 4370 |
11.86 |
| 2026-06-18 12:00 |
00:56:01.03 |
+03:29:53.3 |
HIP 4370 |
10.41 |
| 2026-06-19 00:00 |
00:56:13.23 |
+03:30:53.3 |
HIP 4370 |
9.86 |
| 2026-06-19 12:00 |
00:56:25.31 |
+03:31:52.5 |
HIP 4370 |
10.31 |
| 2026-06-20 00:00 |
00:56:37.26 |
+03:32:50.9 |
HIP 4370 |
11.63 |
| 2026-06-20 12:00 |
00:56:49.10 |
+03:33:48.3 |
HIP 4370 |
13.54 |
| 2026-06-21 00:00 |
00:57:00.80 |
+03:34:44.9 |
HIP 4370 |
15.81 |
| 2026-06-21 12:00 |
00:57:12.38 |
+03:35:40.7 |
HIP 4370 |
18.29 |
| 2026-06-22 00:00 |
00:57:23.84 |
+03:36:35.5 |
HIP 4370 |
20.88 |