| Parameter |
Value |
| Designation |
C/1989 A5 (Shoemaker) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1989-02-26T01:49:07.296960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
77 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1989-01-25.0000000 |
| e |
0.99551906 |
| q (au) |
2.639638 |
| a (au) |
589.081028 |
| i (deg) |
96.558535 |
| Ω (om, deg) |
137.139302 |
| ω (w, deg) |
19.104183 |
| M (ma, deg) |
359.997789 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.268 + 5.033\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.268 |
| n |
5.033 |
| gf |
1.000 |
| gb |
-0.872 |
| 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 |
21:18:27.55 |
-10:55:41.6 |
HIP 105139 |
10.29 |
| 2026-06-01 12:00 |
21:18:26.82 |
-10:55:43.9 |
HIP 105139 |
10.18 |
| 2026-06-02 00:00 |
21:18:26.08 |
-10:55:46.4 |
HIP 105139 |
10.07 |
| 2026-06-02 12:00 |
21:18:25.32 |
-10:55:48.9 |
HIP 105139 |
9.97 |
| 2026-06-03 00:00 |
21:18:24.54 |
-10:55:51.5 |
HIP 105139 |
9.86 |
| 2026-06-03 12:00 |
21:18:23.75 |
-10:55:54.1 |
HIP 105139 |
9.76 |
| 2026-06-04 00:00 |
21:18:22.94 |
-10:55:56.9 |
HIP 105139 |
9.65 |
| 2026-06-04 12:00 |
21:18:22.13 |
-10:55:59.7 |
HIP 105139 |
9.55 |
| 2026-06-05 00:00 |
21:18:21.29 |
-10:56:02.6 |
HIP 105139 |
9.45 |
| 2026-06-05 12:00 |
21:18:20.44 |
-10:56:05.6 |
HIP 105139 |
9.35 |
| 2026-06-06 00:00 |
21:18:19.58 |
-10:56:08.6 |
HIP 105139 |
9.26 |
| 2026-06-06 12:00 |
21:18:18.70 |
-10:56:11.7 |
HIP 105139 |
9.17 |
| 2026-06-07 00:00 |
21:18:17.81 |
-10:56:14.9 |
HIP 105139 |
9.08 |
| 2026-06-07 12:00 |
21:18:16.90 |
-10:56:18.2 |
HIP 105139 |
9.00 |
| 2026-06-08 00:00 |
21:18:15.98 |
-10:56:21.6 |
HIP 105139 |
8.92 |
| 2026-06-08 12:00 |
21:18:15.04 |
-10:56:25.0 |
HIP 105139 |
8.84 |
| 2026-06-09 00:00 |
21:18:14.09 |
-10:56:28.5 |
HIP 105139 |
8.77 |
| 2026-06-09 12:00 |
21:18:13.13 |
-10:56:32.1 |
HIP 105139 |
8.71 |
| 2026-06-10 00:00 |
21:18:12.15 |
-10:56:35.8 |
HIP 105139 |
8.65 |
| 2026-06-10 12:00 |
21:18:11.16 |
-10:56:39.5 |
HIP 105139 |
8.60 |
| 2026-06-11 00:00 |
21:18:10.15 |
-10:56:43.3 |
HIP 105139 |
8.55 |
| 2026-06-11 12:00 |
21:18:09.13 |
-10:56:47.2 |
HIP 105139 |
8.51 |
| 2026-06-12 00:00 |
21:18:08.09 |
-10:56:51.2 |
HIP 105139 |
8.48 |
| 2026-06-12 12:00 |
21:18:07.05 |
-10:56:55.3 |
HIP 105139 |
8.46 |
| 2026-06-13 00:00 |
21:18:05.98 |
-10:56:59.4 |
HIP 105139 |
8.45 |
| 2026-06-13 12:00 |
21:18:04.91 |
-10:57:03.6 |
HIP 105139 |
8.44 |
| 2026-06-14 00:00 |
21:18:03.82 |
-10:57:07.8 |
HIP 105139 |
8.45 |
| 2026-06-14 12:00 |
21:18:02.71 |
-10:57:12.2 |
HIP 105139 |
8.46 |
| 2026-06-15 00:00 |
21:18:01.60 |
-10:57:16.6 |
HIP 105139 |
8.48 |
| 2026-06-15 12:00 |
21:18:00.47 |
-10:57:21.1 |
HIP 105139 |
8.52 |
| 2026-06-16 00:00 |
21:17:59.32 |
-10:57:25.7 |
HIP 105139 |
8.56 |
| 2026-06-16 12:00 |
21:17:58.17 |
-10:57:30.3 |
HIP 105139 |
8.62 |
| 2026-06-17 00:00 |
21:17:57.00 |
-10:57:35.0 |
HIP 105139 |
8.69 |
| 2026-06-17 12:00 |
21:17:55.82 |
-10:57:39.8 |
HIP 105139 |
8.76 |
| 2026-06-18 00:00 |
21:17:54.62 |
-10:57:44.7 |
HIP 105139 |
8.85 |
| 2026-06-18 12:00 |
21:17:53.41 |
-10:57:49.6 |
HIP 105139 |
8.95 |
| 2026-06-19 00:00 |
21:17:52.19 |
-10:57:54.6 |
HIP 105139 |
9.06 |
| 2026-06-19 12:00 |
21:17:50.96 |
-10:57:59.7 |
HIP 105139 |
9.18 |
| 2026-06-20 00:00 |
21:17:49.71 |
-10:58:04.9 |
HIP 105139 |
9.31 |
| 2026-06-20 12:00 |
21:17:48.46 |
-10:58:10.1 |
HIP 105139 |
9.45 |
| 2026-06-21 00:00 |
21:17:47.18 |
-10:58:15.4 |
HIP 105139 |
9.61 |
| 2026-06-21 12:00 |
21:17:45.90 |
-10:58:20.7 |
HIP 105139 |
9.77 |
| 2026-06-22 00:00 |
21:17:44.61 |
-10:58:26.2 |
HIP 105139 |
9.94 |