| Parameter |
Value |
| Designation |
138P/Shoemaker-Levy 7 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-06-12T06:00:38.257920Z |
| Orbit solution date (soln_date, UTC) |
2026-03-31T14:13:33Z |
| Obs used |
134 |
| NEO |
- |
| M1 |
16.700 |
| K1 |
8.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-10-05.0000000 |
| e |
0.52978979 |
| q (au) |
1.703960 |
| a (au) |
3.623827 |
| i (deg) |
10.079832 |
| Ω (om, deg) |
309.438099 |
| ω (w, deg) |
95.552134 |
| M (ma, deg) |
219.804910 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.401 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.401 |
| n |
6.000 |
| gf |
0.806 |
| gb |
-0.787 |
| k |
0.954 |
| 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) |
| 2026-05-12 00:00 |
04:03:40.13 |
+26:22:14.0 |
HIP 18868 |
29.96 |
| 2026-05-12 12:00 |
04:05:10.83 |
+26:25:14.2 |
HIP 19136 |
17.38 |
| 2026-05-13 00:00 |
04:06:41.53 |
+26:28:11.2 |
HIP 19136 |
17.55 |
| 2026-05-13 12:00 |
04:08:12.21 |
+26:31:04.9 |
HIP 19296 |
4.82 |
| 2026-05-14 00:00 |
04:09:42.89 |
+26:33:55.3 |
HIP 19513 |
15.82 |
| 2026-05-14 12:00 |
04:11:13.56 |
+26:36:42.4 |
HIP 19513 |
9.46 |
| 2026-05-15 00:00 |
04:12:44.21 |
+26:39:26.2 |
HIP 19560 |
23.39 |
| 2026-05-15 12:00 |
04:14:14.85 |
+26:42:06.8 |
HIP 19803 |
15.61 |
| 2026-05-16 00:00 |
04:15:45.47 |
+26:44:44.0 |
HIP 19803 |
21.03 |
| 2026-05-16 12:00 |
04:17:16.07 |
+26:47:18.0 |
HIP 19947 |
26.95 |
| 2026-05-17 00:00 |
04:18:46.64 |
+26:49:48.6 |
HIP 20170 |
36.46 |
| 2026-05-17 12:00 |
04:20:17.19 |
+26:52:16.0 |
HIP 20250 |
28.80 |
| 2026-05-18 00:00 |
04:21:47.72 |
+26:54:40.0 |
HIP 20324 |
27.32 |
| 2026-05-18 12:00 |
04:23:18.21 |
+26:57:00.8 |
HIP 20324 |
36.39 |
| 2026-05-19 00:00 |
04:24:48.68 |
+26:59:18.2 |
HIP 20652 |
42.81 |
| 2026-05-19 12:00 |
04:26:19.10 |
+27:01:32.3 |
HIP 20652 |
45.29 |
| 2026-05-20 00:00 |
04:27:49.50 |
+27:03:43.2 |
HIP 20964 |
28.37 |
| 2026-05-20 12:00 |
04:29:19.85 |
+27:05:50.7 |
HIP 20964 |
11.96 |
| 2026-05-21 00:00 |
04:30:50.16 |
+27:07:54.9 |
HIP 20964 |
17.28 |
| 2026-05-21 12:00 |
04:32:20.43 |
+27:09:55.8 |
HIP 20964 |
35.62 |
| 2026-05-22 00:00 |
04:33:50.65 |
+27:11:53.4 |
HIP 21333 |
23.23 |
| 2026-05-22 12:00 |
04:35:20.83 |
+27:13:47.7 |
HIP 21478 |
18.68 |
| 2026-05-23 00:00 |
04:36:50.96 |
+27:15:38.7 |
HIP 21478 |
1.45 |
| 2026-05-23 12:00 |
04:38:21.03 |
+27:17:26.4 |
HIP 21619 |
21.16 |
| 2026-05-24 00:00 |
04:39:51.05 |
+27:19:10.8 |
HIP 21619 |
29.15 |
| 2026-05-24 12:00 |
04:41:21.02 |
+27:20:51.9 |
HIP 21852 |
23.31 |
| 2026-05-25 00:00 |
04:42:50.92 |
+27:22:29.7 |
HIP 21988 |
21.22 |
| 2026-05-25 12:00 |
04:44:20.77 |
+27:24:04.2 |
HIP 21988 |
19.94 |
| 2026-05-26 00:00 |
04:45:50.56 |
+27:25:35.4 |
HIP 22207 |
29.97 |
| 2026-05-26 12:00 |
04:47:20.28 |
+27:27:03.4 |
HIP 22207 |
28.95 |
| 2026-05-27 00:00 |
04:48:49.94 |
+27:28:28.1 |
HIP 22409 |
17.73 |
| 2026-05-27 12:00 |
04:50:19.52 |
+27:29:49.5 |
HIP 22409 |
20.03 |
| 2026-05-28 00:00 |
04:51:49.05 |
+27:31:07.6 |
HIP 22697 |
26.11 |
| 2026-05-28 12:00 |
04:53:18.49 |
+27:32:22.5 |
HIP 22697 |
22.58 |
| 2026-05-29 00:00 |
04:54:47.87 |
+27:33:34.1 |
HIP 22920 |
22.38 |
| 2026-05-29 12:00 |
04:56:17.17 |
+27:34:42.5 |
HIP 22920 |
16.13 |
| 2026-05-30 00:00 |
04:57:46.40 |
+27:35:47.6 |
HIP 23056 |
13.29 |
| 2026-05-30 12:00 |
04:59:15.55 |
+27:36:49.5 |
HIP 23228 |
19.25 |
| 2026-05-31 00:00 |
05:00:44.62 |
+27:37:48.2 |
HIP 23228 |
21.47 |
| 2026-05-31 12:00 |
05:02:13.60 |
+27:38:43.7 |
HIP 23570 |
25.22 |
| 2026-06-01 00:00 |
05:03:42.51 |
+27:39:35.9 |
HIP 23570 |
8.70 |
| 2026-06-01 12:00 |
05:05:11.32 |
+27:40:24.9 |
HIP 23614 |
7.51 |
| 2026-06-02 00:00 |
05:06:40.05 |
+27:41:10.7 |
HIP 23614 |
27.04 |