138P/Shoemaker-Levy 7
| Parameter |
Value |
| Designation |
138P/Shoemaker-Levy 7 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2005-07-19T09:32:42.092160Z |
| Orbit solution date (soln_date, UTC) |
2025-09-16T18:41:04Z |
| Obs used |
126 |
| NEO |
- |
| M1 |
16.600 |
| K1 |
8.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-12-16.0000000 |
| e |
0.52940680 |
| q (au) |
1.705721 |
| a (au) |
3.624618 |
| i (deg) |
10.079607 |
| Ω (om, deg) |
309.442437 |
| ω (w, deg) |
95.558220 |
| M (ma, deg) |
177.905796 |
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) |
| 2026-02-03 00:00 |
23:33:13.48 |
+04:45:39.9 |
HIP 116257 |
7.68 |
| 2026-02-03 12:00 |
23:34:24.31 |
+04:53:26.5 |
HIP 116257 |
21.45 |
| 2026-02-04 00:00 |
23:35:35.27 |
+05:01:13.9 |
HIP 116459 |
4.21 |
| 2026-02-04 12:00 |
23:36:46.36 |
+05:09:02.1 |
HIP 116459 |
15.54 |
| 2026-02-05 00:00 |
23:37:57.60 |
+05:16:51.0 |
HIP 116459 |
34.87 |
| 2026-02-05 12:00 |
23:39:08.96 |
+05:24:40.6 |
HIP 116771 |
17.60 |
| 2026-02-06 00:00 |
23:40:20.47 |
+05:32:31.0 |
HIP 116771 |
7.80 |
| 2026-02-06 12:00 |
23:41:32.11 |
+05:40:22.0 |
HIP 116771 |
23.86 |
| 2026-02-07 00:00 |
23:42:43.89 |
+05:48:13.7 |
HIP 117179 |
40.24 |
| 2026-02-07 12:00 |
23:43:55.81 |
+05:56:06.1 |
HIP 117179 |
23.47 |
| 2026-02-08 00:00 |
23:45:07.86 |
+06:03:59.0 |
HIP 117179 |
15.69 |
| 2026-02-08 12:00 |
23:46:20.05 |
+06:11:52.6 |
HIP 117179 |
26.64 |
| 2026-02-09 00:00 |
23:47:32.38 |
+06:19:46.8 |
HIP 117459 |
22.53 |
| 2026-02-09 12:00 |
23:48:44.85 |
+06:27:41.6 |
HIP 117459 |
3.47 |
| 2026-02-10 00:00 |
23:49:57.45 |
+06:35:36.9 |
HIP 117459 |
17.06 |
| 2026-02-10 12:00 |
23:51:10.18 |
+06:43:32.7 |
HIP 117781 |
29.33 |
| 2026-02-11 00:00 |
23:52:23.06 |
+06:51:29.1 |
HIP 117781 |
14.71 |
| 2026-02-11 12:00 |
23:53:36.07 |
+06:59:26.0 |
HIP 117781 |
18.82 |
| 2026-02-12 00:00 |
23:54:49.22 |
+07:07:23.3 |
HIP 117927 |
5.57 |
| 2026-02-12 12:00 |
23:56:02.50 |
+07:15:21.1 |
HIP 117927 |
17.53 |
| 2026-02-13 00:00 |
23:57:15.93 |
+07:23:19.3 |
HIP 118063 |
5.67 |
| 2026-02-13 12:00 |
23:58:29.48 |
+07:31:18.0 |
HIP 118200 |
8.30 |
| 2026-02-14 00:00 |
23:59:43.18 |
+07:39:17.0 |
HIP 118200 |
17.49 |
| 2026-02-14 12:00 |
00:00:57.01 |
+07:47:16.4 |
HIP 21 |
16.64 |
| 2026-02-15 00:00 |
00:02:10.98 |
+07:55:16.2 |
HIP 247 |
24.23 |
| 2026-02-15 12:00 |
00:03:25.08 |
+08:03:16.3 |
HIP 247 |
13.49 |
| 2026-02-16 00:00 |
00:04:39.32 |
+08:11:16.7 |
HIP 247 |
24.06 |
| 2026-02-16 12:00 |
00:05:53.70 |
+08:19:17.3 |
HIP 551 |
23.66 |
| 2026-02-17 00:00 |
00:07:08.21 |
+08:27:18.3 |
HIP 551 |
13.55 |
| 2026-02-17 12:00 |
00:08:22.86 |
+08:35:19.4 |
HIP 807 |
23.40 |
| 2026-02-18 00:00 |
00:09:37.64 |
+08:43:20.8 |
HIP 807 |
10.01 |
| 2026-02-18 12:00 |
00:10:52.56 |
+08:51:22.4 |
HIP 807 |
21.58 |
| 2026-02-19 00:00 |
00:12:07.61 |
+08:59:24.1 |
HIP 954 |
10.27 |
| 2026-02-19 12:00 |
00:13:22.80 |
+09:07:25.9 |
HIP 1073 |
11.67 |
| 2026-02-20 00:00 |
00:14:38.12 |
+09:15:27.9 |
HIP 1196 |
26.70 |
| 2026-02-20 12:00 |
00:15:53.58 |
+09:23:30.0 |
HIP 1446 |
32.07 |
| 2026-02-21 00:00 |
00:17:09.17 |
+09:31:32.1 |
HIP 1446 |
12.63 |
| 2026-02-21 12:00 |
00:18:24.89 |
+09:39:34.3 |
HIP 1447 |
10.53 |
| 2026-02-22 00:00 |
00:19:40.75 |
+09:47:36.4 |
HIP 1635 |
14.71 |
| 2026-02-22 12:00 |
00:20:56.74 |
+09:55:38.6 |
HIP 1635 |
6.85 |
| 2026-02-23 00:00 |
00:22:12.86 |
+10:03:40.7 |
HIP 1810 |
15.41 |
| 2026-02-23 12:00 |
00:23:29.11 |
+10:11:42.8 |
HIP 1810 |
8.25 |
| 2026-02-24 00:00 |
00:24:45.50 |
+10:19:44.8 |
HIP 2035 |
16.79 |