| 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) |
| 2026-06-01 00:00 |
07:52:55.90 |
+49:39:24.2 |
HIP 38419 |
6.99 |
| 2026-06-01 12:00 |
07:52:57.93 |
+49:39:12.0 |
HIP 38419 |
7.26 |
| 2026-06-02 00:00 |
07:52:59.97 |
+49:38:59.8 |
HIP 38419 |
7.55 |
| 2026-06-02 12:00 |
07:53:02.04 |
+49:38:47.7 |
HIP 38419 |
7.84 |
| 2026-06-03 00:00 |
07:53:04.11 |
+49:38:35.6 |
HIP 38419 |
8.15 |
| 2026-06-03 12:00 |
07:53:06.21 |
+49:38:23.6 |
HIP 38419 |
8.46 |
| 2026-06-04 00:00 |
07:53:08.32 |
+49:38:11.7 |
HIP 38419 |
8.79 |
| 2026-06-04 12:00 |
07:53:10.45 |
+49:37:59.8 |
HIP 38419 |
9.12 |
| 2026-06-05 00:00 |
07:53:12.59 |
+49:37:47.9 |
HIP 38419 |
9.46 |
| 2026-06-05 12:00 |
07:53:14.75 |
+49:37:36.2 |
HIP 38419 |
9.81 |
| 2026-06-06 00:00 |
07:53:16.93 |
+49:37:24.5 |
HIP 38419 |
10.17 |
| 2026-06-06 12:00 |
07:53:19.12 |
+49:37:12.8 |
HIP 38419 |
10.53 |
| 2026-06-07 00:00 |
07:53:21.32 |
+49:37:01.2 |
HIP 38419 |
10.89 |
| 2026-06-07 12:00 |
07:53:23.54 |
+49:36:49.7 |
HIP 38419 |
11.27 |
| 2026-06-08 00:00 |
07:53:25.78 |
+49:36:38.2 |
HIP 38419 |
11.64 |
| 2026-06-08 12:00 |
07:53:28.03 |
+49:36:26.8 |
HIP 38419 |
12.02 |
| 2026-06-09 00:00 |
07:53:30.30 |
+49:36:15.5 |
HIP 38419 |
12.41 |
| 2026-06-09 12:00 |
07:53:32.58 |
+49:36:04.2 |
HIP 38419 |
12.80 |
| 2026-06-10 00:00 |
07:53:34.88 |
+49:35:53.0 |
HIP 38419 |
13.19 |
| 2026-06-10 12:00 |
07:53:37.19 |
+49:35:41.9 |
HIP 38419 |
13.59 |
| 2026-06-11 00:00 |
07:53:39.51 |
+49:35:30.8 |
HIP 38419 |
13.99 |
| 2026-06-11 12:00 |
07:53:41.85 |
+49:35:19.8 |
HIP 38419 |
14.39 |
| 2026-06-12 00:00 |
07:53:44.21 |
+49:35:08.9 |
HIP 38419 |
14.80 |
| 2026-06-12 12:00 |
07:53:46.57 |
+49:34:58.0 |
HIP 38419 |
15.21 |
| 2026-06-13 00:00 |
07:53:48.95 |
+49:34:47.2 |
HIP 38642 |
15.38 |
| 2026-06-13 12:00 |
07:53:51.35 |
+49:34:36.5 |
HIP 38642 |
15.29 |
| 2026-06-14 00:00 |
07:53:53.76 |
+49:34:25.8 |
HIP 38642 |
15.22 |
| 2026-06-14 12:00 |
07:53:56.18 |
+49:34:15.3 |
HIP 38642 |
15.15 |
| 2026-06-15 00:00 |
07:53:58.61 |
+49:34:04.7 |
HIP 38642 |
15.10 |
| 2026-06-15 12:00 |
07:54:01.06 |
+49:33:54.3 |
HIP 38642 |
15.06 |
| 2026-06-16 00:00 |
07:54:03.51 |
+49:33:44.0 |
HIP 38642 |
15.02 |
| 2026-06-16 12:00 |
07:54:05.99 |
+49:33:33.7 |
HIP 38642 |
15.00 |
| 2026-06-17 00:00 |
07:54:08.47 |
+49:33:23.5 |
HIP 38642 |
14.98 |
| 2026-06-17 12:00 |
07:54:10.96 |
+49:33:13.4 |
HIP 38642 |
14.98 |
| 2026-06-18 00:00 |
07:54:13.47 |
+49:33:03.3 |
HIP 38642 |
14.99 |
| 2026-06-18 12:00 |
07:54:15.99 |
+49:32:53.4 |
HIP 38642 |
15.01 |
| 2026-06-19 00:00 |
07:54:18.52 |
+49:32:43.5 |
HIP 38642 |
15.04 |
| 2026-06-19 12:00 |
07:54:21.06 |
+49:32:33.7 |
HIP 38642 |
15.08 |
| 2026-06-20 00:00 |
07:54:23.61 |
+49:32:24.0 |
HIP 38642 |
15.13 |
| 2026-06-20 12:00 |
07:54:26.18 |
+49:32:14.4 |
HIP 38642 |
15.20 |
| 2026-06-21 00:00 |
07:54:28.75 |
+49:32:04.8 |
HIP 38642 |
15.27 |
| 2026-06-21 12:00 |
07:54:31.34 |
+49:31:55.3 |
HIP 38642 |
15.36 |
| 2026-06-22 00:00 |
07:54:33.93 |
+49:31:46.0 |
HIP 38642 |
15.45 |