| Parameter |
Value |
| Designation |
C/1986 P1 (Wilson) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1987-04-20T18:45:50.837760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
671 |
| NEO |
- |
| M1 |
5.300 |
| K1 |
7.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1987-01-29.0000000 |
| e |
1.00031497 |
| q (au) |
1.199648 |
| a (au) |
-3808.824679 |
| i (deg) |
147.119168 |
| Ω (om, deg) |
111.665561 |
| ω (w, deg) |
238.308426 |
| M (ma, deg) |
-0.000343 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.249 + 3.962\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.249 |
| n |
3.962 |
| gf |
1.000 |
| gb |
-0.519 |
| k |
0.800 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 1986-08-05 |
1987-04-20 |
+0.9682 |
-0.238 |
| 1987-04-21 |
1987-06-28 |
+2.8094 |
-0.131 |
| 1987-06-28 |
1988-01-13 |
-3.5539 |
+1.400 |
| 1988-01-13 |
1988-09-12 |
+0.4903 |
-0.605 |
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 |
04:36:30.57 |
+43:29:06.9 |
HIP 21574 |
17.25 |
| 2026-06-01 12:00 |
04:36:32.99 |
+43:29:10.6 |
HIP 21574 |
16.82 |
| 2026-06-02 00:00 |
04:36:35.40 |
+43:29:14.3 |
HIP 21574 |
16.39 |
| 2026-06-02 12:00 |
04:36:37.82 |
+43:29:18.2 |
HIP 21574 |
15.96 |
| 2026-06-03 00:00 |
04:36:40.24 |
+43:29:22.1 |
HIP 21574 |
15.54 |
| 2026-06-03 12:00 |
04:36:42.65 |
+43:29:26.1 |
HIP 21574 |
15.11 |
| 2026-06-04 00:00 |
04:36:45.07 |
+43:29:30.1 |
HIP 21574 |
14.68 |
| 2026-06-04 12:00 |
04:36:47.48 |
+43:29:34.3 |
HIP 21574 |
14.26 |
| 2026-06-05 00:00 |
04:36:49.90 |
+43:29:38.5 |
HIP 21574 |
13.83 |
| 2026-06-05 12:00 |
04:36:52.31 |
+43:29:42.8 |
HIP 21574 |
13.41 |
| 2026-06-06 00:00 |
04:36:54.72 |
+43:29:47.2 |
HIP 21574 |
12.99 |
| 2026-06-06 12:00 |
04:36:57.13 |
+43:29:51.7 |
HIP 21574 |
12.57 |
| 2026-06-07 00:00 |
04:36:59.54 |
+43:29:56.2 |
HIP 21574 |
12.14 |
| 2026-06-07 12:00 |
04:37:01.94 |
+43:30:00.8 |
HIP 21574 |
11.73 |
| 2026-06-08 00:00 |
04:37:04.35 |
+43:30:05.5 |
HIP 21574 |
11.31 |
| 2026-06-08 12:00 |
04:37:06.75 |
+43:30:10.3 |
HIP 21574 |
10.89 |
| 2026-06-09 00:00 |
04:37:09.15 |
+43:30:15.2 |
HIP 21574 |
10.48 |
| 2026-06-09 12:00 |
04:37:11.55 |
+43:30:20.1 |
HIP 21574 |
10.06 |
| 2026-06-10 00:00 |
04:37:13.94 |
+43:30:25.1 |
HIP 21574 |
9.65 |
| 2026-06-10 12:00 |
04:37:16.33 |
+43:30:30.2 |
HIP 21574 |
9.25 |
| 2026-06-11 00:00 |
04:37:18.72 |
+43:30:35.4 |
HIP 21574 |
8.84 |
| 2026-06-11 12:00 |
04:37:21.11 |
+43:30:40.6 |
HIP 21574 |
8.44 |
| 2026-06-12 00:00 |
04:37:23.49 |
+43:30:45.9 |
HIP 21574 |
8.04 |
| 2026-06-12 12:00 |
04:37:25.87 |
+43:30:51.3 |
HIP 21574 |
7.65 |
| 2026-06-13 00:00 |
04:37:28.25 |
+43:30:56.8 |
HIP 21574 |
7.26 |
| 2026-06-13 12:00 |
04:37:30.62 |
+43:31:02.3 |
HIP 21574 |
6.88 |
| 2026-06-14 00:00 |
04:37:32.99 |
+43:31:07.9 |
HIP 21574 |
6.51 |
| 2026-06-14 12:00 |
04:37:35.35 |
+43:31:13.6 |
HIP 21574 |
6.14 |
| 2026-06-15 00:00 |
04:37:37.71 |
+43:31:19.3 |
HIP 21574 |
5.78 |
| 2026-06-15 12:00 |
04:37:40.07 |
+43:31:25.2 |
HIP 21574 |
5.44 |
| 2026-06-16 00:00 |
04:37:42.42 |
+43:31:31.1 |
HIP 21574 |
5.10 |
| 2026-06-16 12:00 |
04:37:44.77 |
+43:31:37.1 |
HIP 21574 |
4.79 |
| 2026-06-17 00:00 |
04:37:47.11 |
+43:31:43.1 |
HIP 21574 |
4.49 |
| 2026-06-17 12:00 |
04:37:49.44 |
+43:31:49.2 |
HIP 21574 |
4.22 |
| 2026-06-18 00:00 |
04:37:51.77 |
+43:31:55.4 |
HIP 21574 |
3.98 |
| 2026-06-18 12:00 |
04:37:54.10 |
+43:32:01.7 |
HIP 21574 |
3.77 |
| 2026-06-19 00:00 |
04:37:56.42 |
+43:32:08.0 |
HIP 21574 |
3.59 |
| 2026-06-19 12:00 |
04:37:58.73 |
+43:32:14.4 |
HIP 21574 |
3.47 |
| 2026-06-20 00:00 |
04:38:01.04 |
+43:32:20.9 |
HIP 21574 |
3.39 |
| 2026-06-20 12:00 |
04:38:03.34 |
+43:32:27.4 |
HIP 21574 |
3.37 |
| 2026-06-21 00:00 |
04:38:05.64 |
+43:32:34.0 |
HIP 21574 |
3.40 |
| 2026-06-21 12:00 |
04:38:07.92 |
+43:32:40.7 |
HIP 21574 |
3.48 |
| 2026-06-22 00:00 |
04:38:10.21 |
+43:32:47.4 |
HIP 21574 |
3.61 |