| 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) |
| 2026-07-29 00:00 |
11:31:57.59 |
+08:17:43.8 |
HIP 56234 |
26.28 |
| 2026-07-29 12:00 |
11:32:14.18 |
+08:15:40.2 |
HIP 56234 |
25.32 |
| 2026-07-30 00:00 |
11:32:30.84 |
+08:13:36.3 |
HIP 56386 |
21.25 |
| 2026-07-30 12:00 |
11:32:47.57 |
+08:11:32.1 |
HIP 56386 |
16.91 |
| 2026-07-31 00:00 |
11:33:04.38 |
+08:09:27.5 |
HIP 56386 |
12.75 |
| 2026-07-31 12:00 |
11:33:21.25 |
+08:07:22.6 |
HIP 56386 |
9.06 |
| 2026-08-01 00:00 |
11:33:38.20 |
+08:05:17.4 |
HIP 56386 |
6.73 |
| 2026-08-01 12:00 |
11:33:55.21 |
+08:03:11.8 |
HIP 56386 |
7.25 |
| 2026-08-02 00:00 |
11:34:12.29 |
+08:01:05.9 |
HIP 56386 |
10.22 |
| 2026-08-02 12:00 |
11:34:29.45 |
+07:58:59.7 |
HIP 56386 |
14.19 |
| 2026-08-03 00:00 |
11:34:46.67 |
+07:56:53.2 |
HIP 56571 |
17.21 |
| 2026-08-03 12:00 |
11:35:03.95 |
+07:54:46.3 |
HIP 56571 |
14.55 |
| 2026-08-04 00:00 |
11:35:21.31 |
+07:52:39.2 |
HIP 56571 |
13.13 |
| 2026-08-04 12:00 |
11:35:38.73 |
+07:50:31.7 |
HIP 56571 |
13.38 |
| 2026-08-05 00:00 |
11:35:56.21 |
+07:48:24.0 |
HIP 56571 |
15.24 |
| 2026-08-05 12:00 |
11:36:13.77 |
+07:46:15.9 |
HIP 56571 |
18.23 |
| 2026-08-06 00:00 |
11:36:31.38 |
+07:44:07.5 |
HIP 56571 |
21.90 |
| 2026-08-06 12:00 |
11:36:49.06 |
+07:41:58.9 |
HIP 56571 |
25.98 |
| 2026-08-07 00:00 |
11:37:06.80 |
+07:39:49.9 |
HIP 56812 |
29.53 |
| 2026-08-07 12:00 |
11:37:24.61 |
+07:37:40.7 |
HIP 56812 |
24.66 |
| 2026-08-08 00:00 |
11:37:42.48 |
+07:35:31.2 |
HIP 56812 |
19.80 |
| 2026-08-08 12:00 |
11:38:00.40 |
+07:33:21.4 |
HIP 56812 |
14.97 |
| 2026-08-09 00:00 |
11:38:18.39 |
+07:31:11.4 |
HIP 56812 |
10.23 |
| 2026-08-09 12:00 |
11:38:36.44 |
+07:29:01.0 |
HIP 56812 |
5.86 |
| 2026-08-10 00:00 |
11:38:54.55 |
+07:26:50.4 |
HIP 56812 |
3.66 |
| 2026-08-10 12:00 |
11:39:12.72 |
+07:24:39.6 |
HIP 56812 |
6.51 |
| 2026-08-11 00:00 |
11:39:30.95 |
+07:22:28.5 |
HIP 56812 |
11.04 |
| 2026-08-11 12:00 |
11:39:49.24 |
+07:20:17.1 |
HIP 56812 |
15.88 |
| 2026-08-12 00:00 |
11:40:07.58 |
+07:18:05.5 |
HIP 56812 |
20.83 |
| 2026-08-12 12:00 |
11:40:25.98 |
+07:15:53.7 |
HIP 56812 |
25.83 |
| 2026-08-13 00:00 |
11:40:44.43 |
+07:13:41.6 |
HIP 56812 |
30.87 |
| 2026-08-13 12:00 |
11:41:02.94 |
+07:11:29.3 |
HIP 57071 |
26.72 |
| 2026-08-14 00:00 |
11:41:21.51 |
+07:09:16.7 |
HIP 57071 |
22.67 |
| 2026-08-14 12:00 |
11:41:40.12 |
+07:07:04.0 |
HIP 57071 |
19.12 |
| 2026-08-15 00:00 |
11:41:58.79 |
+07:04:51.0 |
HIP 57071 |
16.43 |
| 2026-08-15 12:00 |
11:42:17.51 |
+07:02:37.8 |
HIP 57071 |
15.06 |
| 2026-08-16 00:00 |
11:42:36.29 |
+07:00:24.4 |
HIP 57071 |
15.40 |
| 2026-08-16 12:00 |
11:42:55.11 |
+06:58:10.8 |
HIP 57071 |
17.35 |
| 2026-08-17 00:00 |
11:43:13.99 |
+06:55:57.0 |
HIP 57071 |
20.47 |
| 2026-08-17 12:00 |
11:43:32.91 |
+06:53:43.0 |
HIP 57071 |
24.31 |
| 2026-08-18 00:00 |
11:43:51.88 |
+06:51:28.8 |
HIP 57339 |
25.13 |
| 2026-08-18 12:00 |
11:44:10.90 |
+06:49:14.4 |
HIP 57339 |
22.11 |
| 2026-08-19 00:00 |
11:44:29.97 |
+06:46:59.9 |
HIP 57339 |
20.01 |