| Parameter |
Value |
| Designation |
C/1986 E1 (Shoemaker) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1986-03-11T06:37:30.054720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
37 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1986-06-17.0000000 |
| e |
0.94684032 |
| q (au) |
3.593858 |
| a (au) |
67.604972 |
| i (deg) |
159.808447 |
| Ω (om, deg) |
294.843600 |
| ω (w, deg) |
123.567998 |
| M (ma, deg) |
0.173276 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.195 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.195 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.502 |
| k |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
01:21:55.87 |
-12:53:15.0 |
HIP 6391 |
11.58 |
| 2026-07-29 12:00 |
01:21:55.28 |
-12:53:29.4 |
HIP 6391 |
11.38 |
| 2026-07-30 00:00 |
01:21:54.67 |
-12:53:43.9 |
HIP 6391 |
11.19 |
| 2026-07-30 12:00 |
01:21:54.05 |
-12:53:58.5 |
HIP 6391 |
11.00 |
| 2026-07-31 00:00 |
01:21:53.41 |
-12:54:13.2 |
HIP 6391 |
10.82 |
| 2026-07-31 12:00 |
01:21:52.75 |
-12:54:27.9 |
HIP 6391 |
10.64 |
| 2026-08-01 00:00 |
01:21:52.08 |
-12:54:42.7 |
HIP 6391 |
10.47 |
| 2026-08-01 12:00 |
01:21:51.39 |
-12:54:57.5 |
HIP 6391 |
10.31 |
| 2026-08-02 00:00 |
01:21:50.68 |
-12:55:12.5 |
HIP 6391 |
10.15 |
| 2026-08-02 12:00 |
01:21:49.96 |
-12:55:27.4 |
HIP 6391 |
9.99 |
| 2026-08-03 00:00 |
01:21:49.22 |
-12:55:42.5 |
HIP 6391 |
9.85 |
| 2026-08-03 12:00 |
01:21:48.47 |
-12:55:57.6 |
HIP 6391 |
9.72 |
| 2026-08-04 00:00 |
01:21:47.70 |
-12:56:12.8 |
HIP 6391 |
9.59 |
| 2026-08-04 12:00 |
01:21:46.91 |
-12:56:28.0 |
HIP 6391 |
9.47 |
| 2026-08-05 00:00 |
01:21:46.11 |
-12:56:43.3 |
HIP 6391 |
9.37 |
| 2026-08-05 12:00 |
01:21:45.29 |
-12:56:58.6 |
HIP 6391 |
9.28 |
| 2026-08-06 00:00 |
01:21:44.45 |
-12:57:14.0 |
HIP 6391 |
9.20 |
| 2026-08-06 12:00 |
01:21:43.60 |
-12:57:29.5 |
HIP 6391 |
9.13 |
| 2026-08-07 00:00 |
01:21:42.73 |
-12:57:45.0 |
HIP 6391 |
9.07 |
| 2026-08-07 12:00 |
01:21:41.84 |
-12:58:00.5 |
HIP 6391 |
9.03 |
| 2026-08-08 00:00 |
01:21:40.94 |
-12:58:16.1 |
HIP 6391 |
9.01 |
| 2026-08-08 12:00 |
01:21:40.03 |
-12:58:31.8 |
HIP 6391 |
9.00 |
| 2026-08-09 00:00 |
01:21:39.09 |
-12:58:47.5 |
HIP 6391 |
9.00 |
| 2026-08-09 12:00 |
01:21:38.15 |
-12:59:03.3 |
HIP 6391 |
9.02 |
| 2026-08-10 00:00 |
01:21:37.18 |
-12:59:19.1 |
HIP 6391 |
9.06 |
| 2026-08-10 12:00 |
01:21:36.20 |
-12:59:34.9 |
HIP 6391 |
9.11 |
| 2026-08-11 00:00 |
01:21:35.20 |
-12:59:50.8 |
HIP 6391 |
9.18 |
| 2026-08-11 12:00 |
01:21:34.19 |
-13:00:06.8 |
HIP 6391 |
9.27 |
| 2026-08-12 00:00 |
01:21:33.16 |
-13:00:22.8 |
HIP 6391 |
9.37 |
| 2026-08-12 12:00 |
01:21:32.12 |
-13:00:38.8 |
HIP 6391 |
9.49 |
| 2026-08-13 00:00 |
01:21:31.06 |
-13:00:54.9 |
HIP 6391 |
9.63 |
| 2026-08-13 12:00 |
01:21:29.99 |
-13:01:11.0 |
HIP 6391 |
9.78 |
| 2026-08-14 00:00 |
01:21:28.90 |
-13:01:27.1 |
HIP 6391 |
9.94 |
| 2026-08-14 12:00 |
01:21:27.79 |
-13:01:43.3 |
HIP 6391 |
10.12 |
| 2026-08-15 00:00 |
01:21:26.67 |
-13:01:59.5 |
HIP 6391 |
10.32 |
| 2026-08-15 12:00 |
01:21:25.54 |
-13:02:15.8 |
HIP 6391 |
10.53 |
| 2026-08-16 00:00 |
01:21:24.39 |
-13:02:32.1 |
HIP 6391 |
10.75 |
| 2026-08-16 12:00 |
01:21:23.22 |
-13:02:48.4 |
HIP 6391 |
10.98 |
| 2026-08-17 00:00 |
01:21:22.04 |
-13:03:04.7 |
HIP 6391 |
11.23 |
| 2026-08-17 12:00 |
01:21:20.84 |
-13:03:21.1 |
HIP 6391 |
11.49 |
| 2026-08-18 00:00 |
01:21:19.63 |
-13:03:37.5 |
HIP 6391 |
11.76 |
| 2026-08-18 12:00 |
01:21:18.41 |
-13:03:54.0 |
HIP 6391 |
12.04 |
| 2026-08-19 00:00 |
01:21:17.17 |
-13:04:10.4 |
HIP 6391 |
12.34 |