| Parameter |
Value |
| Designation |
C/1984 U1 (Shoemaker) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1984-09-03T10:51:18.192960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
60 |
| NEO |
- |
| M1 |
8.100 |
| K1 |
7.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1985-06-15.0000000 |
| e |
0.99440837 |
| q (au) |
5.489111 |
| a (au) |
981.666043 |
| i (deg) |
179.212301 |
| Ω (om, deg) |
238.298457 |
| ω (w, deg) |
182.819832 |
| M (ma, deg) |
0.009118 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.829 + 3.472\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.829 |
| n |
3.472 |
| 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) |
| 2026-03-26 00:00 |
18:00:43.94 |
-23:50:37.2 |
HIP 88116 |
13.00 |
| 2026-03-26 12:00 |
18:00:43.67 |
-23:50:37.4 |
HIP 88116 |
12.94 |
| 2026-03-27 00:00 |
18:00:43.38 |
-23:50:37.6 |
HIP 88116 |
12.88 |
| 2026-03-27 12:00 |
18:00:43.08 |
-23:50:37.7 |
HIP 88116 |
12.81 |
| 2026-03-28 00:00 |
18:00:42.75 |
-23:50:37.9 |
HIP 88116 |
12.73 |
| 2026-03-28 12:00 |
18:00:42.41 |
-23:50:38.1 |
HIP 88116 |
12.66 |
| 2026-03-29 00:00 |
18:00:42.05 |
-23:50:38.3 |
HIP 88116 |
12.57 |
| 2026-03-29 12:00 |
18:00:41.67 |
-23:50:38.5 |
HIP 88116 |
12.49 |
| 2026-03-30 00:00 |
18:00:41.27 |
-23:50:38.7 |
HIP 88116 |
12.40 |
| 2026-03-30 12:00 |
18:00:40.86 |
-23:50:38.9 |
HIP 88116 |
12.30 |
| 2026-03-31 00:00 |
18:00:40.42 |
-23:50:39.1 |
HIP 88116 |
12.21 |
| 2026-03-31 12:00 |
18:00:39.97 |
-23:50:39.3 |
HIP 88116 |
12.11 |
| 2026-04-01 00:00 |
18:00:39.50 |
-23:50:39.5 |
HIP 88116 |
12.00 |
| 2026-04-01 12:00 |
18:00:39.02 |
-23:50:39.7 |
HIP 88116 |
11.89 |
| 2026-04-02 00:00 |
18:00:38.51 |
-23:50:39.9 |
HIP 88116 |
11.78 |
| 2026-04-02 12:00 |
18:00:37.99 |
-23:50:40.1 |
HIP 88116 |
11.66 |
| 2026-04-03 00:00 |
18:00:37.45 |
-23:50:40.3 |
HIP 88116 |
11.54 |
| 2026-04-03 12:00 |
18:00:36.89 |
-23:50:40.4 |
HIP 88116 |
11.41 |
| 2026-04-04 00:00 |
18:00:36.32 |
-23:50:40.6 |
HIP 88116 |
11.28 |
| 2026-04-04 12:00 |
18:00:35.72 |
-23:50:40.8 |
HIP 88116 |
11.15 |
| 2026-04-05 00:00 |
18:00:35.11 |
-23:50:41.0 |
HIP 88116 |
11.01 |
| 2026-04-05 12:00 |
18:00:34.49 |
-23:50:41.2 |
HIP 88116 |
10.87 |
| 2026-04-06 00:00 |
18:00:33.84 |
-23:50:41.4 |
HIP 88116 |
10.72 |
| 2026-04-06 12:00 |
18:00:33.18 |
-23:50:41.6 |
HIP 88116 |
10.58 |
| 2026-04-07 00:00 |
18:00:32.50 |
-23:50:41.8 |
HIP 88116 |
10.42 |
| 2026-04-07 12:00 |
18:00:31.80 |
-23:50:42.0 |
HIP 88116 |
10.27 |
| 2026-04-08 00:00 |
18:00:31.08 |
-23:50:42.2 |
HIP 88116 |
10.11 |
| 2026-04-08 12:00 |
18:00:30.35 |
-23:50:42.3 |
HIP 88116 |
9.94 |
| 2026-04-09 00:00 |
18:00:29.60 |
-23:50:42.5 |
HIP 88116 |
9.77 |
| 2026-04-09 12:00 |
18:00:28.83 |
-23:50:42.7 |
HIP 88116 |
9.60 |
| 2026-04-10 00:00 |
18:00:28.05 |
-23:50:42.9 |
HIP 88116 |
9.42 |
| 2026-04-10 12:00 |
18:00:27.25 |
-23:50:43.1 |
HIP 88116 |
9.24 |
| 2026-04-11 00:00 |
18:00:26.43 |
-23:50:43.3 |
HIP 88116 |
9.06 |
| 2026-04-11 12:00 |
18:00:25.59 |
-23:50:43.4 |
HIP 88116 |
8.87 |
| 2026-04-12 00:00 |
18:00:24.74 |
-23:50:43.6 |
HIP 88116 |
8.68 |
| 2026-04-12 12:00 |
18:00:23.87 |
-23:50:43.8 |
HIP 88116 |
8.49 |
| 2026-04-13 00:00 |
18:00:22.98 |
-23:50:44.0 |
HIP 88116 |
8.29 |
| 2026-04-13 12:00 |
18:00:22.08 |
-23:50:44.2 |
HIP 88116 |
8.09 |
| 2026-04-14 00:00 |
18:00:21.16 |
-23:50:44.3 |
HIP 88116 |
7.89 |
| 2026-04-14 12:00 |
18:00:20.22 |
-23:50:44.5 |
HIP 88116 |
7.68 |
| 2026-04-15 00:00 |
18:00:19.26 |
-23:50:44.7 |
HIP 88116 |
7.47 |
| 2026-04-15 12:00 |
18:00:18.29 |
-23:50:44.9 |
HIP 88116 |
7.25 |
| 2026-04-16 00:00 |
18:00:17.30 |
-23:50:45.1 |
HIP 88116 |
7.03 |