| Parameter |
Value |
| Designation |
138P/Shoemaker-Levy 7 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-06-11T18:10:36.698880Z |
| Orbit solution date (soln_date, UTC) |
2026-09-08T08:47:00Z |
| Obs used |
171 |
| NEO |
- |
| M1 |
16.200 |
| K1 |
9.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-12-28.0000000 |
| e |
0.53054510 |
| q (au) |
1.700540 |
| a (au) |
3.622371 |
| i (deg) |
10.083992 |
| Ω (om, deg) |
309.414913 |
| ω (w, deg) |
95.628205 |
| M (ma, deg) |
336.160361 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.696 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.696 |
| n |
6.000 |
| gf |
0.961 |
| gb |
-0.835 |
| k |
0.991 |
| δ90 |
1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
09:25:47.99 |
+15:56:26.2 |
HIP 46397 |
29.35 |
| 2026-09-20 12:00 |
09:26:37.86 |
+15:51:21.7 |
HIP 46397 |
16.33 |
| 2026-09-21 00:00 |
09:27:27.53 |
+15:46:17.2 |
HIP 46397 |
3.38 |
| 2026-09-21 12:00 |
09:28:17.02 |
+15:41:12.7 |
HIP 46397 |
9.62 |
| 2026-09-22 00:00 |
09:29:06.31 |
+15:36:08.2 |
HIP 46397 |
22.52 |
| 2026-09-22 12:00 |
09:29:55.42 |
+15:31:03.8 |
HIP 46635 |
18.20 |
| 2026-09-23 00:00 |
09:30:44.34 |
+15:25:59.3 |
HIP 46635 |
10.61 |
| 2026-09-23 12:00 |
09:31:33.07 |
+15:20:54.9 |
HIP 46635 |
14.91 |
| 2026-09-24 00:00 |
09:32:21.61 |
+15:15:50.6 |
HIP 46635 |
25.64 |
| 2026-09-24 12:00 |
09:33:09.96 |
+15:10:46.3 |
HIP 46926 |
21.38 |
| 2026-09-25 00:00 |
09:33:58.12 |
+15:05:42.1 |
HIP 46926 |
23.87 |
| 2026-09-25 12:00 |
09:34:46.10 |
+15:00:37.9 |
HIP 46969 |
25.80 |
| 2026-09-26 00:00 |
09:35:33.88 |
+14:55:33.8 |
HIP 46969 |
26.44 |
| 2026-09-26 12:00 |
09:36:21.48 |
+14:50:29.8 |
HIP 47211 |
28.10 |
| 2026-09-27 00:00 |
09:37:08.89 |
+14:45:26.0 |
HIP 47266 |
27.67 |
| 2026-09-27 12:00 |
09:37:56.11 |
+14:40:22.2 |
HIP 47266 |
19.56 |
| 2026-09-28 00:00 |
09:38:43.14 |
+14:35:18.5 |
HIP 47368 |
11.18 |
| 2026-09-28 12:00 |
09:39:29.99 |
+14:30:15.0 |
HIP 47368 |
8.01 |
| 2026-09-29 00:00 |
09:40:16.64 |
+14:25:11.6 |
HIP 47368 |
17.61 |
| 2026-09-29 12:00 |
09:41:03.11 |
+14:20:08.4 |
HIP 47503 |
12.60 |
| 2026-09-30 00:00 |
09:41:49.38 |
+14:15:05.3 |
HIP 47503 |
13.02 |
| 2026-09-30 12:00 |
09:42:35.47 |
+14:10:02.4 |
HIP 47723 |
18.75 |
| 2026-10-01 00:00 |
09:43:21.37 |
+14:04:59.7 |
HIP 47723 |
6.59 |
| 2026-10-01 12:00 |
09:44:07.08 |
+13:59:57.1 |
HIP 47723 |
5.78 |
| 2026-10-02 00:00 |
09:44:52.60 |
+13:54:54.8 |
HIP 47723 |
17.85 |
| 2026-10-02 12:00 |
09:45:37.93 |
+13:49:52.7 |
HIP 47930 |
23.66 |
| 2026-10-03 00:00 |
09:46:23.07 |
+13:44:50.8 |
HIP 47930 |
18.51 |
| 2026-10-03 12:00 |
09:47:08.02 |
+13:39:49.1 |
HIP 48060 |
15.24 |
| 2026-10-04 00:00 |
09:47:52.78 |
+13:34:47.7 |
HIP 48060 |
6.15 |
| 2026-10-04 12:00 |
09:48:37.34 |
+13:29:46.5 |
HIP 48060 |
11.37 |
| 2026-10-05 00:00 |
09:49:21.72 |
+13:24:45.6 |
HIP 48152 |
20.97 |
| 2026-10-05 12:00 |
09:50:05.90 |
+13:19:44.9 |
HIP 48324 |
20.86 |
| 2026-10-06 00:00 |
09:50:49.89 |
+13:14:44.6 |
HIP 48324 |
11.16 |
| 2026-10-06 12:00 |
09:51:33.68 |
+13:09:44.5 |
HIP 48324 |
9.64 |
| 2026-10-07 00:00 |
09:52:17.28 |
+13:04:44.8 |
HIP 48324 |
18.36 |
| 2026-10-07 12:00 |
09:53:00.69 |
+12:59:45.4 |
HIP 48324 |
29.22 |
| 2026-10-08 00:00 |
09:53:43.90 |
+12:54:46.3 |
HIP 48361 |
35.41 |
| 2026-10-08 12:00 |
09:54:26.91 |
+12:49:47.5 |
HIP 48361 |
43.61 |
| 2026-10-09 00:00 |
09:55:09.73 |
+12:44:49.2 |
HIP 48841 |
42.89 |
| 2026-10-09 12:00 |
09:55:52.35 |
+12:39:51.1 |
HIP 48841 |
31.39 |
| 2026-10-10 00:00 |
09:56:34.78 |
+12:34:53.5 |
HIP 48841 |
19.94 |
| 2026-10-10 12:00 |
09:57:17.00 |
+12:29:56.2 |
HIP 48841 |
8.61 |
| 2026-10-11 00:00 |
09:57:59.03 |
+12:24:59.4 |
HIP 48841 |
3.46 |