| 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) |
| 2026-05-12 00:00 |
07:51:50.25 |
+49:48:07.5 |
HIP 38334 |
10.28 |
| 2026-05-12 12:00 |
07:51:51.49 |
+49:47:53.8 |
HIP 38334 |
10.25 |
| 2026-05-13 00:00 |
07:51:52.75 |
+49:47:40.2 |
HIP 38334 |
10.23 |
| 2026-05-13 12:00 |
07:51:54.03 |
+49:47:26.6 |
HIP 38334 |
10.22 |
| 2026-05-14 00:00 |
07:51:55.33 |
+49:47:13.0 |
HIP 38419 |
10.07 |
| 2026-05-14 12:00 |
07:51:56.66 |
+49:46:59.4 |
HIP 38419 |
9.79 |
| 2026-05-15 00:00 |
07:51:58.00 |
+49:46:45.8 |
HIP 38419 |
9.51 |
| 2026-05-15 12:00 |
07:51:59.37 |
+49:46:32.3 |
HIP 38419 |
9.24 |
| 2026-05-16 00:00 |
07:52:00.77 |
+49:46:18.7 |
HIP 38419 |
8.96 |
| 2026-05-16 12:00 |
07:52:02.18 |
+49:46:05.2 |
HIP 38419 |
8.69 |
| 2026-05-17 00:00 |
07:52:03.61 |
+49:45:51.8 |
HIP 38419 |
8.42 |
| 2026-05-17 12:00 |
07:52:05.07 |
+49:45:38.3 |
HIP 38419 |
8.16 |
| 2026-05-18 00:00 |
07:52:06.54 |
+49:45:24.9 |
HIP 38419 |
7.90 |
| 2026-05-18 12:00 |
07:52:08.04 |
+49:45:11.5 |
HIP 38419 |
7.64 |
| 2026-05-19 00:00 |
07:52:09.56 |
+49:44:58.2 |
HIP 38419 |
7.39 |
| 2026-05-19 12:00 |
07:52:11.10 |
+49:44:44.8 |
HIP 38419 |
7.15 |
| 2026-05-20 00:00 |
07:52:12.66 |
+49:44:31.5 |
HIP 38419 |
6.92 |
| 2026-05-20 12:00 |
07:52:14.24 |
+49:44:18.3 |
HIP 38419 |
6.69 |
| 2026-05-21 00:00 |
07:52:15.84 |
+49:44:05.0 |
HIP 38419 |
6.48 |
| 2026-05-21 12:00 |
07:52:17.46 |
+49:43:51.8 |
HIP 38419 |
6.27 |
| 2026-05-22 00:00 |
07:52:19.10 |
+49:43:38.7 |
HIP 38419 |
6.08 |
| 2026-05-22 12:00 |
07:52:20.76 |
+49:43:25.5 |
HIP 38419 |
5.91 |
| 2026-05-23 00:00 |
07:52:22.44 |
+49:43:12.5 |
HIP 38419 |
5.75 |
| 2026-05-23 12:00 |
07:52:24.14 |
+49:42:59.4 |
HIP 38419 |
5.61 |
| 2026-05-24 00:00 |
07:52:25.86 |
+49:42:46.4 |
HIP 38419 |
5.50 |
| 2026-05-24 12:00 |
07:52:27.60 |
+49:42:33.4 |
HIP 38419 |
5.40 |
| 2026-05-25 00:00 |
07:52:29.36 |
+49:42:20.5 |
HIP 38419 |
5.33 |
| 2026-05-25 12:00 |
07:52:31.14 |
+49:42:07.6 |
HIP 38419 |
5.28 |
| 2026-05-26 00:00 |
07:52:32.93 |
+49:41:54.7 |
HIP 38419 |
5.26 |
| 2026-05-26 12:00 |
07:52:34.75 |
+49:41:41.9 |
HIP 38419 |
5.27 |
| 2026-05-27 00:00 |
07:52:36.58 |
+49:41:29.2 |
HIP 38419 |
5.31 |
| 2026-05-27 12:00 |
07:52:38.43 |
+49:41:16.5 |
HIP 38419 |
5.37 |
| 2026-05-28 00:00 |
07:52:40.30 |
+49:41:03.8 |
HIP 38419 |
5.46 |
| 2026-05-28 12:00 |
07:52:42.19 |
+49:40:51.2 |
HIP 38419 |
5.57 |
| 2026-05-29 00:00 |
07:52:44.09 |
+49:40:38.6 |
HIP 38419 |
5.71 |
| 2026-05-29 12:00 |
07:52:46.02 |
+49:40:26.1 |
HIP 38419 |
5.88 |
| 2026-05-30 00:00 |
07:52:47.96 |
+49:40:13.6 |
HIP 38419 |
6.06 |
| 2026-05-30 12:00 |
07:52:49.92 |
+49:40:01.2 |
HIP 38419 |
6.27 |
| 2026-05-31 00:00 |
07:52:51.89 |
+49:39:48.8 |
HIP 38419 |
6.49 |
| 2026-05-31 12:00 |
07:52:53.89 |
+49:39:36.5 |
HIP 38419 |
6.73 |
| 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 |