| Parameter |
Value |
| Designation |
C/1983 R1 (Shoemaker) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1983-11-23T19:05:28.720320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
117 |
| NEO |
- |
| M1 |
5.800 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1983-12-05.0000000 |
| e |
1.00019923 |
| q (au) |
3.344912 |
| a (au) |
-16789.101324 |
| i (deg) |
137.597258 |
| Ω (om, deg) |
164.683890 |
| ω (w, deg) |
176.039037 |
| M (ma, deg) |
0.000005 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.970 + 5.968\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.970 |
| n |
5.968 |
| gf |
1.000 |
| gb |
-0.719 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
11:53:17.78 |
-20:36:33.0 |
HIP 57986 |
16.07 |
| 2026-07-29 12:00 |
11:53:18.82 |
-20:36:30.6 |
HIP 57986 |
15.96 |
| 2026-07-30 00:00 |
11:53:19.87 |
-20:36:28.2 |
HIP 57986 |
15.86 |
| 2026-07-30 12:00 |
11:53:20.93 |
-20:36:25.9 |
HIP 57986 |
15.76 |
| 2026-07-31 00:00 |
11:53:22.00 |
-20:36:23.8 |
HIP 57986 |
15.66 |
| 2026-07-31 12:00 |
11:53:23.08 |
-20:36:21.8 |
HIP 57986 |
15.57 |
| 2026-08-01 00:00 |
11:53:24.17 |
-20:36:19.9 |
HIP 57986 |
15.48 |
| 2026-08-01 12:00 |
11:53:25.28 |
-20:36:18.1 |
HIP 57986 |
15.40 |
| 2026-08-02 00:00 |
11:53:26.39 |
-20:36:16.4 |
HIP 57986 |
15.32 |
| 2026-08-02 12:00 |
11:53:27.52 |
-20:36:14.9 |
HIP 57986 |
15.25 |
| 2026-08-03 00:00 |
11:53:28.65 |
-20:36:13.4 |
HIP 57986 |
15.19 |
| 2026-08-03 12:00 |
11:53:29.80 |
-20:36:12.1 |
HIP 57986 |
15.13 |
| 2026-08-04 00:00 |
11:53:30.96 |
-20:36:10.9 |
HIP 57986 |
15.08 |
| 2026-08-04 12:00 |
11:53:32.12 |
-20:36:09.8 |
HIP 57986 |
15.03 |
| 2026-08-05 00:00 |
11:53:33.30 |
-20:36:08.9 |
HIP 57986 |
14.99 |
| 2026-08-05 12:00 |
11:53:34.49 |
-20:36:08.0 |
HIP 57986 |
14.96 |
| 2026-08-06 00:00 |
11:53:35.69 |
-20:36:07.3 |
HIP 57986 |
14.93 |
| 2026-08-06 12:00 |
11:53:36.90 |
-20:36:06.6 |
HIP 57986 |
14.91 |
| 2026-08-07 00:00 |
11:53:38.12 |
-20:36:06.1 |
HIP 57986 |
14.90 |
| 2026-08-07 12:00 |
11:53:39.35 |
-20:36:05.7 |
HIP 57986 |
14.90 |
| 2026-08-08 00:00 |
11:53:40.58 |
-20:36:05.5 |
HIP 57986 |
14.90 |
| 2026-08-08 12:00 |
11:53:41.83 |
-20:36:05.3 |
HIP 57986 |
14.91 |
| 2026-08-09 00:00 |
11:53:43.09 |
-20:36:05.3 |
HIP 57986 |
14.93 |
| 2026-08-09 12:00 |
11:53:44.36 |
-20:36:05.3 |
HIP 57986 |
14.96 |
| 2026-08-10 00:00 |
11:53:45.64 |
-20:36:05.5 |
HIP 57986 |
14.99 |
| 2026-08-10 12:00 |
11:53:46.92 |
-20:36:05.8 |
HIP 57986 |
15.04 |
| 2026-08-11 00:00 |
11:53:48.22 |
-20:36:06.3 |
HIP 57986 |
15.09 |
| 2026-08-11 12:00 |
11:53:49.53 |
-20:36:06.8 |
HIP 57986 |
15.15 |
| 2026-08-12 00:00 |
11:53:50.84 |
-20:36:07.4 |
HIP 57986 |
15.22 |
| 2026-08-12 12:00 |
11:53:52.16 |
-20:36:08.2 |
HIP 57986 |
15.29 |
| 2026-08-13 00:00 |
11:53:53.50 |
-20:36:09.1 |
HIP 57986 |
15.38 |
| 2026-08-13 12:00 |
11:53:54.84 |
-20:36:10.1 |
HIP 57986 |
15.47 |
| 2026-08-14 00:00 |
11:53:56.19 |
-20:36:11.2 |
HIP 57986 |
15.57 |
| 2026-08-14 12:00 |
11:53:57.55 |
-20:36:12.5 |
HIP 57986 |
15.68 |
| 2026-08-15 00:00 |
11:53:58.92 |
-20:36:13.8 |
HIP 57986 |
15.80 |
| 2026-08-15 12:00 |
11:54:00.29 |
-20:36:15.3 |
HIP 57986 |
15.92 |
| 2026-08-16 00:00 |
11:54:01.68 |
-20:36:16.8 |
HIP 57986 |
16.05 |
| 2026-08-16 12:00 |
11:54:03.07 |
-20:36:18.5 |
HIP 57986 |
16.19 |
| 2026-08-17 00:00 |
11:54:04.47 |
-20:36:20.3 |
HIP 57986 |
16.34 |
| 2026-08-17 12:00 |
11:54:05.88 |
-20:36:22.3 |
HIP 57986 |
16.50 |
| 2026-08-18 00:00 |
11:54:07.30 |
-20:36:24.3 |
HIP 57986 |
16.66 |
| 2026-08-18 12:00 |
11:54:08.72 |
-20:36:26.4 |
HIP 57986 |
16.84 |
| 2026-08-19 00:00 |
11:54:10.16 |
-20:36:28.7 |
HIP 57986 |
17.02 |