C/2010 G2 (Hill)
| Parameter |
Value |
| Designation |
C/2010 G2 (Hill) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-09-02T01:12:35.795520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:42Z |
| Obs used |
4103 |
| NEO |
- |
| M1 |
10.800 |
| K1 |
6.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-07-30.0000000 |
| e |
0.97940713 |
| q (au) |
1.980774 |
| a (au) |
96.187351 |
| i (deg) |
103.745283 |
| Ω (om, deg) |
246.781006 |
| ω (w, deg) |
137.425281 |
| M (ma, deg) |
359.964425 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.330 + 2.265\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.330 |
| n |
2.265 |
| gf |
1.000 |
| gb |
-0.998 |
| k |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2010-04-10 |
2010-08-28 |
+14.8129 |
-10.677 |
| 2010-08-28 |
2011-05-04 |
-8.0013 |
+3.774 |
| 2011-05-04 |
2011-09-02 |
+19.9294 |
-7.377 |
| 2011-09-02 |
2012-01-01 |
+7.1177 |
-2.882 |
| 2012-01-01 |
2013-03-06 |
+3.5813 |
-2.363 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
22:48:05.81 |
-84:27:54.9 |
HIP 112859 |
12.99 |
| 2026-02-03 12:00 |
22:48:36.85 |
-84:27:25.3 |
HIP 112859 |
12.27 |
| 2026-02-04 00:00 |
22:49:07.94 |
-84:26:56.0 |
HIP 112859 |
11.57 |
| 2026-02-04 12:00 |
22:49:39.09 |
-84:26:27.1 |
HIP 112859 |
10.91 |
| 2026-02-05 00:00 |
22:50:10.28 |
-84:25:58.4 |
HIP 112859 |
10.29 |
| 2026-02-05 12:00 |
22:50:41.53 |
-84:25:30.1 |
HIP 112859 |
9.72 |
| 2026-02-06 00:00 |
22:51:12.83 |
-84:25:02.1 |
HIP 112859 |
9.21 |
| 2026-02-06 12:00 |
22:51:44.18 |
-84:24:34.5 |
HIP 112859 |
8.77 |
| 2026-02-07 00:00 |
22:52:15.58 |
-84:24:07.1 |
HIP 112859 |
8.41 |
| 2026-02-07 12:00 |
22:52:47.03 |
-84:23:40.2 |
HIP 112859 |
8.14 |
| 2026-02-08 00:00 |
22:53:18.52 |
-84:23:13.5 |
HIP 112859 |
7.96 |
| 2026-02-08 12:00 |
22:53:50.06 |
-84:22:47.2 |
HIP 112859 |
7.89 |
| 2026-02-09 00:00 |
22:54:21.64 |
-84:22:21.2 |
HIP 112859 |
7.93 |
| 2026-02-09 12:00 |
22:54:53.27 |
-84:21:55.6 |
HIP 112859 |
8.08 |
| 2026-02-10 00:00 |
22:55:24.94 |
-84:21:30.3 |
HIP 112859 |
8.32 |
| 2026-02-10 12:00 |
22:55:56.65 |
-84:21:05.3 |
HIP 112859 |
8.65 |
| 2026-02-11 00:00 |
22:56:28.41 |
-84:20:40.7 |
HIP 112859 |
9.07 |
| 2026-02-11 12:00 |
22:57:00.20 |
-84:20:16.4 |
HIP 112859 |
9.55 |
| 2026-02-12 00:00 |
22:57:32.04 |
-84:19:52.5 |
HIP 112859 |
10.10 |
| 2026-02-12 12:00 |
22:58:03.91 |
-84:19:28.9 |
HIP 112859 |
10.69 |
| 2026-02-13 00:00 |
22:58:35.82 |
-84:19:05.7 |
HIP 112859 |
11.33 |
| 2026-02-13 12:00 |
22:59:07.77 |
-84:18:42.8 |
HIP 112859 |
12.00 |
| 2026-02-14 00:00 |
22:59:39.75 |
-84:18:20.3 |
HIP 112859 |
12.70 |
| 2026-02-14 12:00 |
23:00:11.77 |
-84:17:58.1 |
HIP 112859 |
13.43 |
| 2026-02-15 00:00 |
23:00:43.82 |
-84:17:36.2 |
HIP 112859 |
14.17 |
| 2026-02-15 12:00 |
23:01:15.91 |
-84:17:14.8 |
HIP 112859 |
14.94 |
| 2026-02-16 00:00 |
23:01:48.02 |
-84:16:53.6 |
HIP 112859 |
15.71 |
| 2026-02-16 12:00 |
23:02:20.17 |
-84:16:32.9 |
HIP 112859 |
16.50 |
| 2026-02-17 00:00 |
23:02:52.35 |
-84:16:12.5 |
HIP 112859 |
17.30 |
| 2026-02-17 12:00 |
23:03:24.55 |
-84:15:52.4 |
HIP 112859 |
18.11 |
| 2026-02-18 00:00 |
23:03:56.79 |
-84:15:32.7 |
HIP 112859 |
18.93 |
| 2026-02-18 12:00 |
23:04:29.05 |
-84:15:13.4 |
HIP 112859 |
19.75 |
| 2026-02-19 00:00 |
23:05:01.33 |
-84:14:54.4 |
HIP 112859 |
20.58 |
| 2026-02-19 12:00 |
23:05:33.64 |
-84:14:35.8 |
HIP 112859 |
21.41 |
| 2026-02-20 00:00 |
23:06:05.98 |
-84:14:17.5 |
HIP 112859 |
22.25 |
| 2026-02-20 12:00 |
23:06:38.33 |
-84:13:59.6 |
HIP 112859 |
23.09 |
| 2026-02-21 00:00 |
23:07:10.71 |
-84:13:42.1 |
HIP 112859 |
23.93 |
| 2026-02-21 12:00 |
23:07:43.11 |
-84:13:24.9 |
HIP 112859 |
24.77 |
| 2026-02-22 00:00 |
23:08:15.53 |
-84:13:08.1 |
HIP 112859 |
25.62 |
| 2026-02-22 12:00 |
23:08:47.97 |
-84:12:51.7 |
HIP 112859 |
26.47 |
| 2026-02-23 00:00 |
23:09:20.42 |
-84:12:35.6 |
HIP 112859 |
27.32 |
| 2026-02-23 12:00 |
23:09:52.89 |
-84:12:19.9 |
HIP 112859 |
28.17 |
| 2026-02-24 00:00 |
23:10:25.38 |
-84:12:04.6 |
HIP 112859 |
29.02 |