| Parameter |
Value |
| Designation |
199P/Shoemaker 4 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2009-04-08T02:25:25.942080Z |
| Orbit solution date (soln_date, UTC) |
2024-08-18T18:42:22Z |
| Obs used |
863 |
| NEO |
- |
| M1 |
7.400 |
| K1 |
16.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-04-27.0000000 |
| e |
0.50752456 |
| q (au) |
2.929047 |
| a (au) |
5.947599 |
| i (deg) |
24.756182 |
| Ω (om, deg) |
92.622289 |
| ω (w, deg) |
191.826638 |
| M (ma, deg) |
50.887927 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.239 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.239 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.902 |
| 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) |
| 2026-09-20 00:00 |
04:37:19.87 |
+07:16:32.6 |
HIP 21575 |
8.91 |
| 2026-09-20 12:00 |
04:37:18.95 |
+07:15:58.4 |
HIP 21575 |
9.30 |
| 2026-09-21 00:00 |
04:37:17.86 |
+07:15:24.1 |
HIP 21575 |
9.76 |
| 2026-09-21 12:00 |
04:37:16.63 |
+07:14:49.5 |
HIP 21575 |
10.26 |
| 2026-09-22 00:00 |
04:37:15.24 |
+07:14:14.7 |
HIP 21575 |
10.82 |
| 2026-09-22 12:00 |
04:37:13.70 |
+07:13:39.7 |
HIP 21575 |
11.43 |
| 2026-09-23 00:00 |
04:37:12.00 |
+07:13:04.6 |
HIP 21575 |
12.08 |
| 2026-09-23 12:00 |
04:37:10.16 |
+07:12:29.3 |
HIP 21575 |
12.77 |
| 2026-09-24 00:00 |
04:37:08.15 |
+07:11:53.8 |
HIP 21575 |
13.51 |
| 2026-09-24 12:00 |
04:37:06.00 |
+07:11:18.2 |
HIP 21575 |
14.28 |
| 2026-09-25 00:00 |
04:37:03.69 |
+07:10:42.4 |
HIP 21575 |
15.08 |
| 2026-09-25 12:00 |
04:37:01.23 |
+07:10:06.4 |
HIP 21575 |
15.92 |
| 2026-09-26 00:00 |
04:36:58.62 |
+07:09:30.3 |
HIP 21575 |
16.80 |
| 2026-09-26 12:00 |
04:36:55.86 |
+07:08:54.1 |
HIP 21575 |
17.71 |
| 2026-09-27 00:00 |
04:36:52.94 |
+07:08:17.7 |
HIP 21575 |
18.65 |
| 2026-09-27 12:00 |
04:36:49.87 |
+07:07:41.2 |
HIP 21575 |
19.62 |
| 2026-09-28 00:00 |
04:36:46.65 |
+07:07:04.6 |
HIP 21575 |
20.63 |
| 2026-09-28 12:00 |
04:36:43.27 |
+07:06:27.8 |
HIP 21575 |
21.66 |
| 2026-09-29 00:00 |
04:36:39.74 |
+07:05:51.0 |
HIP 21575 |
22.73 |
| 2026-09-29 12:00 |
04:36:36.06 |
+07:05:14.0 |
HIP 21575 |
23.83 |
| 2026-09-30 00:00 |
04:36:32.23 |
+07:04:36.9 |
HIP 21575 |
24.97 |
| 2026-09-30 12:00 |
04:36:28.25 |
+07:03:59.7 |
HIP 21575 |
26.13 |
| 2026-10-01 00:00 |
04:36:24.11 |
+07:03:22.4 |
HIP 21575 |
27.33 |
| 2026-10-01 12:00 |
04:36:19.82 |
+07:02:45.1 |
HIP 21575 |
28.56 |
| 2026-10-02 00:00 |
04:36:15.39 |
+07:02:07.6 |
HIP 21575 |
29.82 |
| 2026-10-02 12:00 |
04:36:10.79 |
+07:01:30.1 |
HIP 21575 |
31.11 |
| 2026-10-03 00:00 |
04:36:06.05 |
+07:00:52.6 |
HIP 21346 |
31.75 |
| 2026-10-03 12:00 |
04:36:01.16 |
+07:00:14.9 |
HIP 21346 |
31.56 |
| 2026-10-04 00:00 |
04:35:56.12 |
+06:59:37.2 |
HIP 21346 |
31.40 |
| 2026-10-04 12:00 |
04:35:50.92 |
+06:58:59.5 |
HIP 21346 |
31.30 |
| 2026-10-05 00:00 |
04:35:45.58 |
+06:58:21.7 |
HIP 21346 |
31.24 |
| 2026-10-05 12:00 |
04:35:40.09 |
+06:57:43.9 |
HIP 21321 |
30.64 |
| 2026-10-06 00:00 |
04:35:34.44 |
+06:57:06.0 |
HIP 21321 |
29.39 |
| 2026-10-06 12:00 |
04:35:28.65 |
+06:56:28.1 |
HIP 21321 |
28.15 |
| 2026-10-07 00:00 |
04:35:22.71 |
+06:55:50.2 |
HIP 21321 |
26.94 |
| 2026-10-07 12:00 |
04:35:16.62 |
+06:55:12.3 |
HIP 21321 |
25.75 |
| 2026-10-08 00:00 |
04:35:10.39 |
+06:54:34.4 |
HIP 21321 |
24.60 |
| 2026-10-08 12:00 |
04:35:04.00 |
+06:53:56.6 |
HIP 21321 |
23.50 |
| 2026-10-09 00:00 |
04:34:57.47 |
+06:53:18.7 |
HIP 21321 |
22.47 |
| 2026-10-09 12:00 |
04:34:50.79 |
+06:52:40.8 |
HIP 21321 |
21.53 |
| 2026-10-10 00:00 |
04:34:43.97 |
+06:52:03.0 |
HIP 21321 |
20.69 |
| 2026-10-10 12:00 |
04:34:37.01 |
+06:51:25.2 |
HIP 21321 |
19.98 |
| 2026-10-11 00:00 |
04:34:29.89 |
+06:50:47.5 |
HIP 21321 |
19.43 |