51P/Harrington
| Parameter |
Value |
| Designation |
51P/Harrington |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-08-12T09:52:15.983040Z |
| Orbit solution date (soln_date, UTC) |
2022-10-24T10:18:34Z |
| Obs used |
99 |
| NEO |
- |
| M1 |
18.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-06-21.0000000 |
| e |
0.54204517 |
| q (au) |
1.699112 |
| a (au) |
3.710217 |
| i (deg) |
5.423652 |
| Ω (om, deg) |
83.717710 |
| ω (w, deg) |
269.163564 |
| M (ma, deg) |
93.586186 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.171 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.171 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.607 |
| k |
0.920 |
| δ90 |
10.000 |
| 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 |
11:53:32.34 |
+07:31:14.8 |
HIP 57924 |
12.26 |
| 2026-02-03 12:00 |
11:53:22.48 |
+07:32:47.2 |
HIP 57924 |
9.41 |
| 2026-02-04 00:00 |
11:53:12.47 |
+07:34:20.4 |
HIP 57924 |
6.55 |
| 2026-02-04 12:00 |
11:53:02.30 |
+07:35:54.3 |
HIP 57924 |
3.76 |
| 2026-02-05 00:00 |
11:52:51.97 |
+07:37:29.0 |
HIP 57924 |
1.71 |
| 2026-02-05 12:00 |
11:52:41.48 |
+07:39:04.5 |
HIP 57924 |
3.16 |
| 2026-02-06 00:00 |
11:52:30.85 |
+07:40:40.7 |
HIP 57924 |
6.00 |
| 2026-02-06 12:00 |
11:52:20.06 |
+07:42:17.6 |
HIP 57924 |
9.04 |
| 2026-02-07 00:00 |
11:52:09.11 |
+07:43:55.3 |
HIP 57924 |
12.16 |
| 2026-02-07 12:00 |
11:51:58.02 |
+07:45:33.6 |
HIP 57924 |
15.33 |
| 2026-02-08 00:00 |
11:51:46.78 |
+07:47:12.6 |
HIP 57924 |
18.55 |
| 2026-02-08 12:00 |
11:51:35.39 |
+07:48:52.3 |
HIP 57924 |
21.81 |
| 2026-02-09 00:00 |
11:51:23.85 |
+07:50:32.7 |
HIP 57686 |
23.52 |
| 2026-02-09 12:00 |
11:51:12.16 |
+07:52:13.7 |
HIP 57686 |
21.11 |
| 2026-02-10 00:00 |
11:51:00.33 |
+07:53:55.4 |
HIP 57686 |
18.97 |
| 2026-02-10 12:00 |
11:50:48.36 |
+07:55:37.7 |
HIP 57686 |
17.20 |
| 2026-02-11 00:00 |
11:50:36.25 |
+07:57:20.6 |
HIP 57686 |
15.96 |
| 2026-02-11 12:00 |
11:50:24.00 |
+07:59:04.0 |
HIP 57686 |
15.41 |
| 2026-02-12 00:00 |
11:50:11.60 |
+08:00:48.1 |
HIP 57686 |
15.63 |
| 2026-02-12 12:00 |
11:49:59.07 |
+08:02:32.7 |
HIP 57686 |
16.61 |
| 2026-02-13 00:00 |
11:49:46.41 |
+08:04:17.9 |
HIP 57686 |
18.26 |
| 2026-02-13 12:00 |
11:49:33.61 |
+08:06:03.6 |
HIP 57686 |
20.44 |
| 2026-02-14 00:00 |
11:49:20.68 |
+08:07:49.8 |
HIP 57562 |
22.32 |
| 2026-02-14 12:00 |
11:49:07.62 |
+08:09:36.6 |
HIP 57562 |
18.71 |
| 2026-02-15 00:00 |
11:48:54.42 |
+08:11:23.8 |
HIP 57562 |
15.10 |
| 2026-02-15 12:00 |
11:48:41.11 |
+08:13:11.5 |
HIP 57562 |
11.53 |
| 2026-02-16 00:00 |
11:48:27.66 |
+08:14:59.6 |
HIP 57562 |
8.10 |
| 2026-02-16 12:00 |
11:48:14.10 |
+08:16:48.2 |
HIP 57562 |
5.17 |
| 2026-02-17 00:00 |
11:48:00.41 |
+08:18:37.2 |
HIP 57562 |
4.10 |
| 2026-02-17 12:00 |
11:47:46.60 |
+08:20:26.6 |
HIP 57562 |
6.05 |
| 2026-02-18 00:00 |
11:47:32.68 |
+08:22:16.4 |
HIP 57562 |
9.32 |
| 2026-02-18 12:00 |
11:47:18.63 |
+08:24:06.5 |
HIP 57562 |
12.97 |
| 2026-02-19 00:00 |
11:47:04.48 |
+08:25:57.0 |
HIP 57562 |
16.77 |
| 2026-02-19 12:00 |
11:46:50.21 |
+08:27:47.9 |
HIP 57562 |
20.65 |
| 2026-02-20 00:00 |
11:46:35.84 |
+08:29:39.0 |
HIP 57328 |
24.10 |
| 2026-02-20 12:00 |
11:46:21.36 |
+08:31:30.4 |
HIP 57328 |
22.58 |
| 2026-02-21 00:00 |
11:46:06.77 |
+08:33:22.2 |
HIP 57328 |
21.71 |
| 2026-02-21 12:00 |
11:45:52.08 |
+08:35:14.2 |
HIP 57328 |
21.57 |
| 2026-02-22 00:00 |
11:45:37.29 |
+08:37:06.4 |
HIP 57328 |
22.19 |
| 2026-02-22 12:00 |
11:45:22.40 |
+08:38:58.8 |
HIP 57328 |
23.53 |
| 2026-02-23 00:00 |
11:45:07.41 |
+08:40:51.5 |
HIP 57328 |
25.48 |
| 2026-02-23 12:00 |
11:44:52.33 |
+08:42:44.3 |
HIP 57258 |
27.02 |
| 2026-02-24 00:00 |
11:44:37.16 |
+08:44:37.4 |
HIP 57258 |
28.41 |