| 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
$$
M_a = (14.696 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
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) |
| 2026-07-29 00:00 |
07:39:41.65 |
+24:11:38.6 |
HIP 37269 |
6.97 |
| 2026-07-29 12:00 |
07:40:51.89 |
+24:07:47.2 |
HIP 37517 |
16.31 |
| 2026-07-30 00:00 |
07:42:01.93 |
+24:03:54.4 |
HIP 37517 |
0.96 |
| 2026-07-30 12:00 |
07:43:11.77 |
+24:00:00.1 |
HIP 37650 |
13.70 |
| 2026-07-31 00:00 |
07:44:21.42 |
+23:56:04.4 |
HIP 37650 |
13.75 |
| 2026-07-31 12:00 |
07:45:30.87 |
+23:52:07.3 |
HIP 37914 |
21.22 |
| 2026-08-01 00:00 |
07:46:40.12 |
+23:48:08.9 |
HIP 37988 |
10.63 |
| 2026-08-01 12:00 |
07:47:49.18 |
+23:44:09.0 |
HIP 37988 |
10.16 |
| 2026-08-02 00:00 |
07:48:58.05 |
+23:40:07.8 |
HIP 37988 |
24.97 |
| 2026-08-02 12:00 |
07:50:06.72 |
+23:36:05.2 |
HIP 38287 |
34.42 |
| 2026-08-03 00:00 |
07:51:15.19 |
+23:32:01.3 |
HIP 38287 |
38.50 |
| 2026-08-03 12:00 |
07:52:23.47 |
+23:27:56.1 |
HIP 38603 |
25.51 |
| 2026-08-04 00:00 |
07:53:31.56 |
+23:23:49.6 |
HIP 38603 |
11.71 |
| 2026-08-04 12:00 |
07:54:39.45 |
+23:19:41.8 |
HIP 38603 |
12.02 |
| 2026-08-05 00:00 |
07:55:47.14 |
+23:15:32.8 |
HIP 38761 |
22.33 |
| 2026-08-05 12:00 |
07:56:54.64 |
+23:11:22.5 |
HIP 38761 |
28.30 |
| 2026-08-06 00:00 |
07:58:01.95 |
+23:07:11.0 |
HIP 39077 |
23.45 |
| 2026-08-06 12:00 |
07:59:09.06 |
+23:02:58.2 |
HIP 39087 |
8.96 |
| 2026-08-07 00:00 |
08:00:15.97 |
+22:58:44.3 |
HIP 39087 |
9.33 |
| 2026-08-07 12:00 |
08:01:22.69 |
+22:54:29.1 |
HIP 39087 |
24.54 |
| 2026-08-08 00:00 |
08:02:29.22 |
+22:50:12.8 |
HIP 39223 |
32.59 |
| 2026-08-08 12:00 |
08:03:35.55 |
+22:45:55.4 |
HIP 39659 |
38.36 |
| 2026-08-09 00:00 |
08:04:41.68 |
+22:41:36.8 |
HIP 39659 |
22.58 |
| 2026-08-09 12:00 |
08:05:47.62 |
+22:37:17.0 |
HIP 39659 |
7.15 |
| 2026-08-10 00:00 |
08:06:53.37 |
+22:32:56.2 |
HIP 39681 |
7.04 |
| 2026-08-10 12:00 |
08:07:58.92 |
+22:28:34.3 |
HIP 39788 |
18.49 |
| 2026-08-11 00:00 |
08:09:04.27 |
+22:24:11.3 |
HIP 39788 |
28.40 |
| 2026-08-11 12:00 |
08:10:09.43 |
+22:19:47.2 |
HIP 39950 |
26.99 |
| 2026-08-12 00:00 |
08:11:14.40 |
+22:15:22.2 |
HIP 40216 |
23.16 |
| 2026-08-12 12:00 |
08:12:19.16 |
+22:10:56.0 |
HIP 40216 |
13.75 |
| 2026-08-13 00:00 |
08:13:23.73 |
+22:06:28.9 |
HIP 40306 |
12.03 |
| 2026-08-13 12:00 |
08:14:28.11 |
+22:02:00.8 |
HIP 40306 |
17.13 |
| 2026-08-14 00:00 |
08:15:32.29 |
+21:57:31.7 |
HIP 40565 |
19.70 |
| 2026-08-14 12:00 |
08:16:36.27 |
+21:53:01.6 |
HIP 40565 |
5.20 |
| 2026-08-15 00:00 |
08:17:40.05 |
+21:48:30.6 |
HIP 40565 |
12.09 |
| 2026-08-15 12:00 |
08:18:43.64 |
+21:43:58.7 |
HIP 40565 |
27.25 |
| 2026-08-16 00:00 |
08:19:47.04 |
+21:39:25.9 |
HIP 40781 |
24.58 |
| 2026-08-16 12:00 |
08:20:50.23 |
+21:34:52.1 |
HIP 40950 |
21.57 |
| 2026-08-17 00:00 |
08:21:53.24 |
+21:30:17.5 |
HIP 40950 |
24.96 |
| 2026-08-17 12:00 |
08:22:56.04 |
+21:25:42.0 |
HIP 41130 |
26.55 |
| 2026-08-18 00:00 |
08:23:58.65 |
+21:21:05.6 |
HIP 41311 |
26.42 |
| 2026-08-18 12:00 |
08:25:01.06 |
+21:16:28.4 |
HIP 41311 |
11.24 |
| 2026-08-19 00:00 |
08:26:03.28 |
+21:11:50.4 |
HIP 41311 |
4.47 |