C/1986 P1 (Wilson)
| 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
$$
M_a = (5.250 + 3.962\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.250 |
| 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 |
+0.9640 |
-0.237 |
| 1987-04-21 |
1987-06-28 |
+3.0667 |
-0.159 |
| 1987-06-28 |
1987-11-19 |
-3.8705 |
+1.509 |
| 1987-11-19 |
1988-02-13 |
+3.4229 |
-2.366 |
| 1988-02-13 |
1988-04-11 |
-1.9956 |
+1.118 |
| 1988-04-11 |
1988-09-12 |
-4.6843 |
+3.061 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
04:32:22.38 |
+43:50:58.3 |
HIP 21175 |
7.70 |
| 2026-02-03 12:00 |
04:32:21.16 |
+43:50:47.1 |
HIP 21175 |
7.51 |
| 2026-02-04 00:00 |
04:32:19.97 |
+43:50:35.9 |
HIP 21175 |
7.34 |
| 2026-02-04 12:00 |
04:32:18.79 |
+43:50:24.7 |
HIP 21175 |
7.17 |
| 2026-02-05 00:00 |
04:32:17.64 |
+43:50:13.5 |
HIP 21175 |
7.00 |
| 2026-02-05 12:00 |
04:32:16.51 |
+43:50:02.2 |
HIP 21175 |
6.85 |
| 2026-02-06 00:00 |
04:32:15.40 |
+43:49:51.0 |
HIP 21175 |
6.70 |
| 2026-02-06 12:00 |
04:32:14.31 |
+43:49:39.8 |
HIP 21175 |
6.56 |
| 2026-02-07 00:00 |
04:32:13.24 |
+43:49:28.5 |
HIP 21175 |
6.42 |
| 2026-02-07 12:00 |
04:32:12.20 |
+43:49:17.3 |
HIP 21175 |
6.30 |
| 2026-02-08 00:00 |
04:32:11.17 |
+43:49:06.1 |
HIP 21175 |
6.18 |
| 2026-02-08 12:00 |
04:32:10.17 |
+43:48:54.8 |
HIP 21175 |
6.06 |
| 2026-02-09 00:00 |
04:32:09.19 |
+43:48:43.6 |
HIP 21175 |
5.96 |
| 2026-02-09 12:00 |
04:32:08.23 |
+43:48:32.4 |
HIP 21175 |
5.86 |
| 2026-02-10 00:00 |
04:32:07.30 |
+43:48:21.1 |
HIP 21175 |
5.77 |
| 2026-02-10 12:00 |
04:32:06.38 |
+43:48:09.9 |
HIP 21175 |
5.69 |
| 2026-02-11 00:00 |
04:32:05.49 |
+43:47:58.7 |
HIP 21175 |
5.62 |
| 2026-02-11 12:00 |
04:32:04.62 |
+43:47:47.5 |
HIP 21175 |
5.56 |
| 2026-02-12 00:00 |
04:32:03.77 |
+43:47:36.3 |
HIP 21175 |
5.50 |
| 2026-02-12 12:00 |
04:32:02.94 |
+43:47:25.1 |
HIP 21175 |
5.45 |
| 2026-02-13 00:00 |
04:32:02.14 |
+43:47:13.9 |
HIP 21175 |
5.41 |
| 2026-02-13 12:00 |
04:32:01.36 |
+43:47:02.7 |
HIP 21175 |
5.37 |
| 2026-02-14 00:00 |
04:32:00.60 |
+43:46:51.6 |
HIP 21175 |
5.34 |
| 2026-02-14 12:00 |
04:31:59.86 |
+43:46:40.4 |
HIP 21175 |
5.32 |
| 2026-02-15 00:00 |
04:31:59.15 |
+43:46:29.3 |
HIP 21175 |
5.31 |
| 2026-02-15 12:00 |
04:31:58.46 |
+43:46:18.2 |
HIP 21175 |
5.30 |
| 2026-02-16 00:00 |
04:31:57.79 |
+43:46:07.1 |
HIP 21175 |
5.30 |
| 2026-02-16 12:00 |
04:31:57.14 |
+43:45:56.0 |
HIP 21175 |
5.30 |
| 2026-02-17 00:00 |
04:31:56.52 |
+43:45:44.9 |
HIP 21175 |
5.31 |
| 2026-02-17 12:00 |
04:31:55.92 |
+43:45:33.9 |
HIP 21175 |
5.33 |
| 2026-02-18 00:00 |
04:31:55.34 |
+43:45:22.8 |
HIP 21175 |
5.35 |
| 2026-02-18 12:00 |
04:31:54.78 |
+43:45:11.8 |
HIP 21175 |
5.37 |
| 2026-02-19 00:00 |
04:31:54.25 |
+43:45:00.8 |
HIP 21175 |
5.40 |
| 2026-02-19 12:00 |
04:31:53.74 |
+43:44:49.8 |
HIP 21175 |
5.43 |
| 2026-02-20 00:00 |
04:31:53.25 |
+43:44:38.9 |
HIP 21175 |
5.47 |
| 2026-02-20 12:00 |
04:31:52.78 |
+43:44:28.0 |
HIP 21175 |
5.51 |
| 2026-02-21 00:00 |
04:31:52.34 |
+43:44:17.1 |
HIP 21175 |
5.55 |
| 2026-02-21 12:00 |
04:31:51.92 |
+43:44:06.2 |
HIP 21175 |
5.60 |
| 2026-02-22 00:00 |
04:31:51.52 |
+43:43:55.3 |
HIP 21175 |
5.64 |
| 2026-02-22 12:00 |
04:31:51.15 |
+43:43:44.5 |
HIP 21175 |
5.69 |
| 2026-02-23 00:00 |
04:31:50.80 |
+43:43:33.7 |
HIP 21175 |
5.74 |
| 2026-02-23 12:00 |
04:31:50.47 |
+43:43:23.0 |
HIP 21175 |
5.80 |
| 2026-02-24 00:00 |
04:31:50.16 |
+43:43:12.2 |
HIP 21175 |
5.85 |