128P/Shoemaker-Holt 1
| Parameter |
Value |
| Designation |
128P/Shoemaker-Holt 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-01-10T18:11:45.499200Z |
| Orbit solution date (soln_date, UTC) |
2026-01-08T08:15:32Z |
| Obs used |
834 |
| NEO |
- |
| M1 |
7.300 |
| K1 |
19.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-12-19.0000000 |
| e |
0.32151222 |
| q (au) |
3.055657 |
| a (au) |
4.503629 |
| i (deg) |
4.363715 |
| Ω (om, deg) |
214.295949 |
| ω (w, deg) |
210.577393 |
| M (ma, deg) |
319.909665 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.259 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.259 |
| n |
6.000 |
| gf |
0.970 |
| gb |
-0.886 |
| k |
0.997 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
00:54:40.10 |
+06:06:52.2 |
HIP 4231 |
21.08 |
| 2026-02-03 12:00 |
00:55:13.93 |
+06:09:55.7 |
HIP 4231 |
28.49 |
| 2026-02-04 00:00 |
00:55:47.90 |
+06:12:59.9 |
HIP 4231 |
36.63 |
| 2026-02-04 12:00 |
00:56:22.00 |
+06:16:04.8 |
HIP 4518 |
33.00 |
| 2026-02-05 00:00 |
00:56:56.24 |
+06:19:10.5 |
HIP 4518 |
30.47 |
| 2026-02-05 12:00 |
00:57:30.60 |
+06:22:16.9 |
HIP 4518 |
30.54 |
| 2026-02-06 00:00 |
00:58:05.10 |
+06:25:24.1 |
HIP 4559 |
25.51 |
| 2026-02-06 12:00 |
00:58:39.73 |
+06:28:31.9 |
HIP 4655 |
17.38 |
| 2026-02-07 00:00 |
00:59:14.48 |
+06:31:40.5 |
HIP 4655 |
9.14 |
| 2026-02-07 12:00 |
00:59:49.37 |
+06:34:49.8 |
HIP 4655 |
5.84 |
| 2026-02-08 00:00 |
01:00:24.38 |
+06:37:59.7 |
HIP 4655 |
12.46 |
| 2026-02-08 12:00 |
01:00:59.52 |
+06:41:10.3 |
HIP 4655 |
21.19 |
| 2026-02-09 00:00 |
01:01:34.79 |
+06:44:21.6 |
HIP 4859 |
20.68 |
| 2026-02-09 12:00 |
01:02:10.18 |
+06:47:33.5 |
HIP 4859 |
13.27 |
| 2026-02-10 00:00 |
01:02:45.69 |
+06:50:46.1 |
HIP 4859 |
9.97 |
| 2026-02-10 12:00 |
01:03:21.34 |
+06:53:59.3 |
HIP 4978 |
10.32 |
| 2026-02-11 00:00 |
01:03:57.10 |
+06:57:13.2 |
HIP 4978 |
11.59 |
| 2026-02-11 12:00 |
01:04:32.99 |
+07:00:27.7 |
HIP 5073 |
4.89 |
| 2026-02-12 00:00 |
01:05:09.00 |
+07:03:42.8 |
HIP 5073 |
4.72 |
| 2026-02-12 12:00 |
01:05:45.13 |
+07:06:58.4 |
HIP 5073 |
14.23 |
| 2026-02-13 00:00 |
01:06:21.38 |
+07:10:14.7 |
HIP 5073 |
23.79 |
| 2026-02-13 12:00 |
01:06:57.75 |
+07:13:31.6 |
HIP 5073 |
33.38 |
| 2026-02-14 00:00 |
01:07:34.24 |
+07:16:49.0 |
HIP 5382 |
24.15 |
| 2026-02-14 12:00 |
01:08:10.85 |
+07:20:07.0 |
HIP 5382 |
15.23 |
| 2026-02-15 00:00 |
01:08:47.57 |
+07:23:25.6 |
HIP 5382 |
8.19 |
| 2026-02-15 12:00 |
01:09:24.41 |
+07:26:44.7 |
HIP 5382 |
9.50 |
| 2026-02-16 00:00 |
01:10:01.37 |
+07:30:04.3 |
HIP 5382 |
17.42 |
| 2026-02-16 12:00 |
01:10:38.44 |
+07:33:24.5 |
HIP 5562 |
19.12 |
| 2026-02-17 00:00 |
01:11:15.63 |
+07:36:45.1 |
HIP 5562 |
12.95 |
| 2026-02-17 12:00 |
01:11:52.93 |
+07:40:06.3 |
HIP 5562 |
12.73 |
| 2026-02-18 00:00 |
01:12:30.34 |
+07:43:28.0 |
HIP 5562 |
18.73 |
| 2026-02-18 12:00 |
01:13:07.87 |
+07:46:50.1 |
HIP 5737 |
15.19 |
| 2026-02-19 00:00 |
01:13:45.51 |
+07:50:12.7 |
HIP 5743 |
15.51 |
| 2026-02-19 12:00 |
01:14:23.25 |
+07:53:35.8 |
HIP 5743 |
21.12 |
| 2026-02-20 00:00 |
01:15:01.11 |
+07:56:59.3 |
HIP 5743 |
29.16 |
| 2026-02-20 12:00 |
01:15:39.07 |
+08:00:23.3 |
HIP 5995 |
22.02 |
| 2026-02-21 00:00 |
01:16:17.14 |
+08:03:47.7 |
HIP 5995 |
14.89 |
| 2026-02-21 12:00 |
01:16:55.32 |
+08:07:12.5 |
HIP 5995 |
12.62 |
| 2026-02-22 00:00 |
01:17:33.61 |
+08:10:37.8 |
HIP 5995 |
17.30 |
| 2026-02-22 12:00 |
01:18:11.99 |
+08:14:03.4 |
HIP 6195 |
21.24 |
| 2026-02-23 00:00 |
01:18:50.49 |
+08:17:29.4 |
HIP 6195 |
11.27 |
| 2026-02-23 12:00 |
01:19:29.08 |
+08:20:55.8 |
HIP 6195 |
2.85 |
| 2026-02-24 00:00 |
01:20:07.78 |
+08:24:22.6 |
HIP 6195 |
9.78 |