| 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
$$
M_a = (5.830 + 3.472\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.830 |
| n |
3.472 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-06-01 00:00 |
17:57:48.09 |
-23:50:52.5 |
HIP 87880 |
10.78 |
| 2026-06-01 12:00 |
17:57:46.00 |
-23:50:52.4 |
HIP 87880 |
10.38 |
| 2026-06-02 00:00 |
17:57:43.91 |
-23:50:52.3 |
HIP 87880 |
9.97 |
| 2026-06-02 12:00 |
17:57:41.81 |
-23:50:52.3 |
HIP 87880 |
9.58 |
| 2026-06-03 00:00 |
17:57:39.70 |
-23:50:52.2 |
HIP 87880 |
9.19 |
| 2026-06-03 12:00 |
17:57:37.59 |
-23:50:52.1 |
HIP 87880 |
8.81 |
| 2026-06-04 00:00 |
17:57:35.48 |
-23:50:52.0 |
HIP 87880 |
8.43 |
| 2026-06-04 12:00 |
17:57:33.36 |
-23:50:52.0 |
HIP 87880 |
8.07 |
| 2026-06-05 00:00 |
17:57:31.23 |
-23:50:51.9 |
HIP 87880 |
7.72 |
| 2026-06-05 12:00 |
17:57:29.11 |
-23:50:51.8 |
HIP 87880 |
7.39 |
| 2026-06-06 00:00 |
17:57:26.97 |
-23:50:51.7 |
HIP 87880 |
7.08 |
| 2026-06-06 12:00 |
17:57:24.83 |
-23:50:51.6 |
HIP 87880 |
6.78 |
| 2026-06-07 00:00 |
17:57:22.69 |
-23:50:51.5 |
HIP 87880 |
6.51 |
| 2026-06-07 12:00 |
17:57:20.54 |
-23:50:51.4 |
HIP 87880 |
6.26 |
| 2026-06-08 00:00 |
17:57:18.39 |
-23:50:51.3 |
HIP 87880 |
6.04 |
| 2026-06-08 12:00 |
17:57:16.23 |
-23:50:51.1 |
HIP 87880 |
5.86 |
| 2026-06-09 00:00 |
17:57:14.07 |
-23:50:51.0 |
HIP 87880 |
5.71 |
| 2026-06-09 12:00 |
17:57:11.91 |
-23:50:50.9 |
HIP 87880 |
5.60 |
| 2026-06-10 00:00 |
17:57:09.74 |
-23:50:50.8 |
HIP 87880 |
5.53 |
| 2026-06-10 12:00 |
17:57:07.57 |
-23:50:50.7 |
HIP 87880 |
5.51 |
| 2026-06-11 00:00 |
17:57:05.40 |
-23:50:50.5 |
HIP 87880 |
5.53 |
| 2026-06-11 12:00 |
17:57:03.22 |
-23:50:50.4 |
HIP 87880 |
5.60 |
| 2026-06-12 00:00 |
17:57:01.04 |
-23:50:50.2 |
HIP 87880 |
5.71 |
| 2026-06-12 12:00 |
17:56:58.86 |
-23:50:50.1 |
HIP 87880 |
5.86 |
| 2026-06-13 00:00 |
17:56:56.68 |
-23:50:49.9 |
HIP 87880 |
6.05 |
| 2026-06-13 12:00 |
17:56:54.49 |
-23:50:49.8 |
HIP 87880 |
6.27 |
| 2026-06-14 00:00 |
17:56:52.30 |
-23:50:49.6 |
HIP 87880 |
6.52 |
| 2026-06-14 12:00 |
17:56:50.11 |
-23:50:49.5 |
HIP 87880 |
6.80 |
| 2026-06-15 00:00 |
17:56:47.92 |
-23:50:49.3 |
HIP 87880 |
7.11 |
| 2026-06-15 12:00 |
17:56:45.72 |
-23:50:49.2 |
HIP 87880 |
7.44 |
| 2026-06-16 00:00 |
17:56:43.52 |
-23:50:49.0 |
HIP 87880 |
7.78 |
| 2026-06-16 12:00 |
17:56:41.33 |
-23:50:48.8 |
HIP 87880 |
8.15 |
| 2026-06-17 00:00 |
17:56:39.13 |
-23:50:48.6 |
HIP 87880 |
8.52 |
| 2026-06-17 12:00 |
17:56:36.93 |
-23:50:48.5 |
HIP 87880 |
8.91 |
| 2026-06-18 00:00 |
17:56:34.73 |
-23:50:48.3 |
HIP 87880 |
9.32 |
| 2026-06-18 12:00 |
17:56:32.52 |
-23:50:48.1 |
HIP 87880 |
9.73 |
| 2026-06-19 00:00 |
17:56:30.32 |
-23:50:47.9 |
HIP 87880 |
10.15 |
| 2026-06-19 12:00 |
17:56:28.12 |
-23:50:47.7 |
HIP 87880 |
10.57 |
| 2026-06-20 00:00 |
17:56:25.92 |
-23:50:47.5 |
HIP 87880 |
11.01 |
| 2026-06-20 12:00 |
17:56:23.71 |
-23:50:47.3 |
HIP 87880 |
11.44 |
| 2026-06-21 00:00 |
17:56:21.51 |
-23:50:47.1 |
HIP 87880 |
11.89 |
| 2026-06-21 12:00 |
17:56:19.31 |
-23:50:46.9 |
HIP 87880 |
12.34 |
| 2026-06-22 00:00 |
17:56:17.10 |
-23:50:46.7 |
HIP 87880 |
12.79 |