| 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) |
| 2026-09-20 00:00 |
12:06:02.73 |
+04:20:09.4 |
HIP 59037 |
8.89 |
| 2026-09-20 12:00 |
12:06:23.66 |
+04:17:51.5 |
HIP 59037 |
6.57 |
| 2026-09-21 00:00 |
12:06:44.59 |
+04:15:33.7 |
HIP 59037 |
8.51 |
| 2026-09-21 12:00 |
12:07:05.54 |
+04:13:16.0 |
HIP 59037 |
12.91 |
| 2026-09-22 00:00 |
12:07:26.49 |
+04:10:58.4 |
HIP 59037 |
18.06 |
| 2026-09-22 12:00 |
12:07:47.45 |
+04:08:40.9 |
HIP 59134 |
22.41 |
| 2026-09-23 00:00 |
12:08:08.41 |
+04:06:23.5 |
HIP 59134 |
25.96 |
| 2026-09-23 12:00 |
12:08:29.39 |
+04:04:06.2 |
HIP 59187 |
24.76 |
| 2026-09-24 00:00 |
12:08:50.36 |
+04:01:49.0 |
HIP 59187 |
23.72 |
| 2026-09-24 12:00 |
12:09:11.35 |
+03:59:31.9 |
HIP 59187 |
24.03 |
| 2026-09-25 00:00 |
12:09:32.34 |
+03:57:15.0 |
HIP 59321 |
23.42 |
| 2026-09-25 12:00 |
12:09:53.33 |
+03:54:58.1 |
HIP 59321 |
23.99 |
| 2026-09-26 00:00 |
12:10:14.33 |
+03:52:41.4 |
HIP 59451 |
23.93 |
| 2026-09-26 12:00 |
12:10:35.33 |
+03:50:24.8 |
HIP 59451 |
20.72 |
| 2026-09-27 00:00 |
12:10:56.33 |
+03:48:08.4 |
HIP 59451 |
18.74 |
| 2026-09-27 12:00 |
12:11:17.34 |
+03:45:52.1 |
HIP 59451 |
18.39 |
| 2026-09-28 00:00 |
12:11:38.35 |
+03:43:35.9 |
HIP 59451 |
19.76 |
| 2026-09-28 12:00 |
12:11:59.36 |
+03:41:19.9 |
HIP 59536 |
18.72 |
| 2026-09-29 00:00 |
12:12:20.37 |
+03:39:04.0 |
HIP 59536 |
15.02 |
| 2026-09-29 12:00 |
12:12:41.38 |
+03:36:48.3 |
HIP 59536 |
12.88 |
| 2026-09-30 00:00 |
12:13:02.39 |
+03:34:32.7 |
HIP 59536 |
13.10 |
| 2026-09-30 12:00 |
12:13:23.40 |
+03:32:17.3 |
HIP 59536 |
15.57 |
| 2026-10-01 00:00 |
12:13:44.41 |
+03:30:02.0 |
HIP 59536 |
19.46 |
| 2026-10-01 12:00 |
12:14:05.42 |
+03:27:46.9 |
HIP 59536 |
24.08 |
| 2026-10-02 00:00 |
12:14:26.43 |
+03:25:32.0 |
HIP 59829 |
26.41 |
| 2026-10-02 12:00 |
12:14:47.43 |
+03:23:17.2 |
HIP 59829 |
22.42 |
| 2026-10-03 00:00 |
12:15:08.43 |
+03:21:02.7 |
HIP 59829 |
19.31 |
| 2026-10-03 12:00 |
12:15:29.43 |
+03:18:48.3 |
HIP 59829 |
17.55 |
| 2026-10-04 00:00 |
12:15:50.42 |
+03:16:34.1 |
HIP 59829 |
17.54 |
| 2026-10-04 12:00 |
12:16:11.41 |
+03:14:20.1 |
HIP 59829 |
19.29 |
| 2026-10-05 00:00 |
12:16:32.39 |
+03:12:06.3 |
HIP 59829 |
22.39 |
| 2026-10-05 12:00 |
12:16:53.37 |
+03:09:52.7 |
HIP 59918 |
18.70 |
| 2026-10-06 00:00 |
12:17:14.34 |
+03:07:39.3 |
HIP 59918 |
14.76 |
| 2026-10-06 12:00 |
12:17:35.30 |
+03:05:26.1 |
HIP 59998 |
10.96 |
| 2026-10-07 00:00 |
12:17:56.26 |
+03:03:13.1 |
HIP 59998 |
6.38 |
| 2026-10-07 12:00 |
12:18:17.20 |
+03:01:00.4 |
HIP 59998 |
5.08 |
| 2026-10-08 00:00 |
12:18:38.14 |
+02:58:47.8 |
HIP 59998 |
8.68 |
| 2026-10-08 12:00 |
12:18:59.06 |
+02:56:35.5 |
HIP 59998 |
13.75 |
| 2026-10-09 00:00 |
12:19:19.97 |
+02:54:23.5 |
HIP 59998 |
19.16 |
| 2026-10-09 12:00 |
12:19:40.88 |
+02:52:11.7 |
HIP 59998 |
24.68 |
| 2026-10-10 00:00 |
12:20:01.77 |
+02:50:00.1 |
HIP 60264 |
21.62 |
| 2026-10-10 12:00 |
12:20:22.65 |
+02:47:48.8 |
HIP 60264 |
16.01 |
| 2026-10-11 00:00 |
12:20:43.51 |
+02:45:37.8 |
HIP 60264 |
10.44 |