| 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) |
| 2026-07-29 00:00 |
01:04:46.66 |
+03:58:57.4 |
HIP 5023 |
15.93 |
| 2026-07-29 12:00 |
01:04:46.48 |
+03:58:35.6 |
HIP 5023 |
16.25 |
| 2026-07-30 00:00 |
01:04:46.11 |
+03:58:12.6 |
HIP 5023 |
16.57 |
| 2026-07-30 12:00 |
01:04:45.57 |
+03:57:48.6 |
HIP 5023 |
16.90 |
| 2026-07-31 00:00 |
01:04:44.85 |
+03:57:23.4 |
HIP 5023 |
17.23 |
| 2026-07-31 12:00 |
01:04:43.95 |
+03:56:57.0 |
HIP 5023 |
17.57 |
| 2026-08-01 00:00 |
01:04:42.87 |
+03:56:29.6 |
HIP 5023 |
17.93 |
| 2026-08-01 12:00 |
01:04:41.61 |
+03:56:01.0 |
HIP 5023 |
18.29 |
| 2026-08-02 00:00 |
01:04:40.16 |
+03:55:31.2 |
HIP 5023 |
18.68 |
| 2026-08-02 12:00 |
01:04:38.54 |
+03:55:00.4 |
HIP 5023 |
19.08 |
| 2026-08-03 00:00 |
01:04:36.73 |
+03:54:28.4 |
HIP 5023 |
19.51 |
| 2026-08-03 12:00 |
01:04:34.74 |
+03:53:55.3 |
HIP 5023 |
19.97 |
| 2026-08-04 00:00 |
01:04:32.57 |
+03:53:21.0 |
HIP 5023 |
20.45 |
| 2026-08-04 12:00 |
01:04:30.22 |
+03:52:45.6 |
HIP 5023 |
20.97 |
| 2026-08-05 00:00 |
01:04:27.68 |
+03:52:09.1 |
HIP 5023 |
21.52 |
| 2026-08-05 12:00 |
01:04:24.96 |
+03:51:31.5 |
HIP 5023 |
22.11 |
| 2026-08-06 00:00 |
01:04:22.05 |
+03:50:52.7 |
HIP 5023 |
22.74 |
| 2026-08-06 12:00 |
01:04:18.96 |
+03:50:12.7 |
HIP 5023 |
23.42 |
| 2026-08-07 00:00 |
01:04:15.69 |
+03:49:31.6 |
HIP 5023 |
24.14 |
| 2026-08-07 12:00 |
01:04:12.23 |
+03:48:49.4 |
HIP 5023 |
24.91 |
| 2026-08-08 00:00 |
01:04:08.59 |
+03:48:06.1 |
HIP 5023 |
25.73 |
| 2026-08-08 12:00 |
01:04:04.76 |
+03:47:21.6 |
HIP 5023 |
26.60 |
| 2026-08-09 00:00 |
01:04:00.74 |
+03:46:36.0 |
HIP 5023 |
27.52 |
| 2026-08-09 12:00 |
01:03:56.54 |
+03:45:49.2 |
HIP 5023 |
28.50 |
| 2026-08-10 00:00 |
01:03:52.16 |
+03:45:01.3 |
HIP 5023 |
29.53 |
| 2026-08-10 12:00 |
01:03:47.59 |
+03:44:12.3 |
HIP 4945 |
29.37 |
| 2026-08-11 00:00 |
01:03:42.83 |
+03:43:22.1 |
HIP 4945 |
28.35 |
| 2026-08-11 12:00 |
01:03:37.89 |
+03:42:30.8 |
HIP 4945 |
27.34 |
| 2026-08-12 00:00 |
01:03:32.77 |
+03:41:38.4 |
HIP 4945 |
26.36 |
| 2026-08-12 12:00 |
01:03:27.46 |
+03:40:44.9 |
HIP 4945 |
25.41 |
| 2026-08-13 00:00 |
01:03:21.96 |
+03:39:50.3 |
HIP 4945 |
24.52 |
| 2026-08-13 12:00 |
01:03:16.28 |
+03:38:54.5 |
HIP 4945 |
23.70 |
| 2026-08-14 00:00 |
01:03:10.41 |
+03:37:57.6 |
HIP 4945 |
22.96 |
| 2026-08-14 12:00 |
01:03:04.37 |
+03:36:59.6 |
HIP 4945 |
22.32 |
| 2026-08-15 00:00 |
01:02:58.13 |
+03:36:00.6 |
HIP 4945 |
21.81 |
| 2026-08-15 12:00 |
01:02:51.72 |
+03:35:00.4 |
HIP 4945 |
21.45 |
| 2026-08-16 00:00 |
01:02:45.12 |
+03:33:59.1 |
HIP 4945 |
21.25 |
| 2026-08-16 12:00 |
01:02:38.34 |
+03:32:56.7 |
HIP 4945 |
21.25 |
| 2026-08-17 00:00 |
01:02:31.38 |
+03:31:53.3 |
HIP 4759 |
21.22 |
| 2026-08-17 12:00 |
01:02:24.23 |
+03:30:48.7 |
HIP 4759 |
19.21 |
| 2026-08-18 00:00 |
01:02:16.91 |
+03:29:43.1 |
HIP 4759 |
17.17 |
| 2026-08-18 12:00 |
01:02:09.40 |
+03:28:36.4 |
HIP 4759 |
15.10 |
| 2026-08-19 00:00 |
01:02:01.72 |
+03:27:28.7 |
HIP 4759 |
13.03 |