| Parameter |
Value |
| Designation |
C/1988 L1 (Shoemaker-Holt-Rodriquez) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1989-06-12T11:09:22.452480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
155 |
| NEO |
- |
| M1 |
9.200 |
| K1 |
4.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1988-11-06.0000000 |
| e |
1.00067716 |
| q (au) |
2.474297 |
| a (au) |
-3653.923503 |
| i (deg) |
97.688560 |
| Ω (om, deg) |
115.255065 |
| ω (w, deg) |
232.145920 |
| M (ma, deg) |
-0.000975 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.401 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.401 |
| n |
2.000 |
| gf |
0.995 |
| gb |
-0.685 |
| k |
0.999 |
| δ90 |
9.990 |
| 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) |
| 2026-07-29 00:00 |
07:58:02.01 |
+49:24:41.6 |
HIP 38824 |
14.87 |
| 2026-07-29 12:00 |
07:58:04.86 |
+49:24:40.0 |
HIP 38824 |
15.27 |
| 2026-07-30 00:00 |
07:58:07.71 |
+49:24:38.4 |
HIP 38824 |
15.68 |
| 2026-07-30 12:00 |
07:58:10.56 |
+49:24:37.0 |
HIP 38824 |
16.09 |
| 2026-07-31 00:00 |
07:58:13.40 |
+49:24:35.7 |
HIP 38824 |
16.51 |
| 2026-07-31 12:00 |
07:58:16.23 |
+49:24:34.5 |
HIP 38824 |
16.92 |
| 2026-08-01 00:00 |
07:58:19.07 |
+49:24:33.4 |
HIP 39097 |
16.55 |
| 2026-08-01 12:00 |
07:58:21.90 |
+49:24:32.5 |
HIP 39097 |
16.13 |
| 2026-08-02 00:00 |
07:58:24.72 |
+49:24:31.6 |
HIP 39097 |
15.71 |
| 2026-08-02 12:00 |
07:58:27.54 |
+49:24:30.9 |
HIP 39097 |
15.30 |
| 2026-08-03 00:00 |
07:58:30.35 |
+49:24:30.3 |
HIP 39097 |
14.88 |
| 2026-08-03 12:00 |
07:58:33.16 |
+49:24:29.8 |
HIP 39097 |
14.47 |
| 2026-08-04 00:00 |
07:58:35.96 |
+49:24:29.5 |
HIP 39097 |
14.06 |
| 2026-08-04 12:00 |
07:58:38.76 |
+49:24:29.2 |
HIP 39097 |
13.66 |
| 2026-08-05 00:00 |
07:58:41.55 |
+49:24:29.1 |
HIP 39097 |
13.25 |
| 2026-08-05 12:00 |
07:58:44.34 |
+49:24:29.1 |
HIP 39097 |
12.85 |
| 2026-08-06 00:00 |
07:58:47.11 |
+49:24:29.2 |
HIP 39097 |
12.46 |
| 2026-08-06 12:00 |
07:58:49.89 |
+49:24:29.4 |
HIP 39097 |
12.06 |
| 2026-08-07 00:00 |
07:58:52.65 |
+49:24:29.8 |
HIP 39097 |
11.68 |
| 2026-08-07 12:00 |
07:58:55.41 |
+49:24:30.3 |
HIP 39097 |
11.29 |
| 2026-08-08 00:00 |
07:58:58.17 |
+49:24:30.9 |
HIP 39097 |
10.91 |
| 2026-08-08 12:00 |
07:59:00.91 |
+49:24:31.6 |
HIP 39097 |
10.54 |
| 2026-08-09 00:00 |
07:59:03.65 |
+49:24:32.4 |
HIP 39097 |
10.17 |
| 2026-08-09 12:00 |
07:59:06.38 |
+49:24:33.4 |
HIP 39097 |
9.81 |
| 2026-08-10 00:00 |
07:59:09.11 |
+49:24:34.4 |
HIP 39097 |
9.45 |
| 2026-08-10 12:00 |
07:59:11.82 |
+49:24:35.6 |
HIP 39097 |
9.10 |
| 2026-08-11 00:00 |
07:59:14.53 |
+49:24:37.0 |
HIP 39097 |
8.76 |
| 2026-08-11 12:00 |
07:59:17.23 |
+49:24:38.4 |
HIP 39097 |
8.43 |
| 2026-08-12 00:00 |
07:59:19.92 |
+49:24:40.0 |
HIP 39097 |
8.11 |
| 2026-08-12 12:00 |
07:59:22.60 |
+49:24:41.6 |
HIP 39097 |
7.79 |
| 2026-08-13 00:00 |
07:59:25.28 |
+49:24:43.5 |
HIP 39097 |
7.49 |
| 2026-08-13 12:00 |
07:59:27.94 |
+49:24:45.4 |
HIP 39097 |
7.21 |
| 2026-08-14 00:00 |
07:59:30.60 |
+49:24:47.4 |
HIP 39097 |
6.94 |
| 2026-08-14 12:00 |
07:59:33.24 |
+49:24:49.6 |
HIP 39097 |
6.68 |
| 2026-08-15 00:00 |
07:59:35.88 |
+49:24:51.9 |
HIP 39097 |
6.44 |
| 2026-08-15 12:00 |
07:59:38.50 |
+49:24:54.3 |
HIP 39097 |
6.22 |
| 2026-08-16 00:00 |
07:59:41.12 |
+49:24:56.9 |
HIP 39097 |
6.02 |
| 2026-08-16 12:00 |
07:59:43.73 |
+49:24:59.5 |
HIP 39097 |
5.85 |
| 2026-08-17 00:00 |
07:59:46.32 |
+49:25:02.3 |
HIP 39097 |
5.70 |
| 2026-08-17 12:00 |
07:59:48.91 |
+49:25:05.2 |
HIP 39097 |
5.57 |
| 2026-08-18 00:00 |
07:59:51.48 |
+49:25:08.2 |
HIP 39097 |
5.48 |
| 2026-08-18 12:00 |
07:59:54.05 |
+49:25:11.4 |
HIP 39097 |
5.41 |
| 2026-08-19 00:00 |
07:59:56.60 |
+49:25:14.6 |
HIP 39097 |
5.38 |