| 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
$$
M_a = (10.346 + 2.260\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.346 |
| n |
2.260 |
| gf |
0.993 |
| gb |
-0.971 |
| k |
1.000 |
| δ90 |
9.997 |
| 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 |
+14.9148 |
-10.749 |
| 2010-08-28 |
2011-05-04 |
-7.9772 |
+3.754 |
| 2011-05-04 |
2011-09-02 |
+19.9398 |
-7.392 |
| 2011-09-02 |
2012-01-01 |
+7.3113 |
-2.940 |
| 2012-01-01 |
2013-03-06 |
+3.5605 |
-2.360 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
00:45:54.69 |
-85:17:37.4 |
HIP 2928 |
11.11 |
| 2026-06-01 12:00 |
00:46:15.30 |
-85:18:28.6 |
HIP 3053 |
11.04 |
| 2026-06-02 00:00 |
00:46:35.73 |
-85:19:20.0 |
HIP 3053 |
10.92 |
| 2026-06-02 12:00 |
00:46:55.97 |
-85:20:11.7 |
HIP 3053 |
10.88 |
| 2026-06-03 00:00 |
00:47:16.02 |
-85:21:03.5 |
HIP 3053 |
10.91 |
| 2026-06-03 12:00 |
00:47:35.88 |
-85:21:55.6 |
HIP 3053 |
11.02 |
| 2026-06-04 00:00 |
00:47:55.54 |
-85:22:47.8 |
HIP 3053 |
11.20 |
| 2026-06-04 12:00 |
00:48:15.00 |
-85:23:40.3 |
HIP 3053 |
11.46 |
| 2026-06-05 00:00 |
00:48:34.26 |
-85:24:33.0 |
HIP 3053 |
11.77 |
| 2026-06-05 12:00 |
00:48:53.31 |
-85:25:25.9 |
HIP 3053 |
12.15 |
| 2026-06-06 00:00 |
00:49:12.16 |
-85:26:19.0 |
HIP 3053 |
12.59 |
| 2026-06-06 12:00 |
00:49:30.80 |
-85:27:12.3 |
HIP 3053 |
13.07 |
| 2026-06-07 00:00 |
00:49:49.23 |
-85:28:05.8 |
HIP 3053 |
13.61 |
| 2026-06-07 12:00 |
00:50:07.44 |
-85:28:59.5 |
HIP 3053 |
14.18 |
| 2026-06-08 00:00 |
00:50:25.43 |
-85:29:53.3 |
HIP 3053 |
14.78 |
| 2026-06-08 12:00 |
00:50:43.20 |
-85:30:47.4 |
HIP 3053 |
15.42 |
| 2026-06-09 00:00 |
00:51:00.74 |
-85:31:41.7 |
HIP 3053 |
16.09 |
| 2026-06-09 12:00 |
00:51:18.06 |
-85:32:36.1 |
HIP 3114 |
16.36 |
| 2026-06-10 00:00 |
00:51:35.14 |
-85:33:30.7 |
HIP 3114 |
16.11 |
| 2026-06-10 12:00 |
00:51:51.99 |
-85:34:25.5 |
HIP 3114 |
15.90 |
| 2026-06-11 00:00 |
00:52:08.61 |
-85:35:20.5 |
HIP 3114 |
15.74 |
| 2026-06-11 12:00 |
00:52:24.98 |
-85:36:15.7 |
HIP 3114 |
15.64 |
| 2026-06-12 00:00 |
00:52:41.10 |
-85:37:11.0 |
HIP 3114 |
15.59 |
| 2026-06-12 12:00 |
00:52:56.97 |
-85:38:06.5 |
HIP 3114 |
15.59 |
| 2026-06-13 00:00 |
00:53:12.60 |
-85:39:02.2 |
HIP 3114 |
15.64 |
| 2026-06-13 12:00 |
00:53:27.96 |
-85:39:58.0 |
HIP 3114 |
15.75 |
| 2026-06-14 00:00 |
00:53:43.07 |
-85:40:54.0 |
HIP 3114 |
15.91 |
| 2026-06-14 12:00 |
00:53:57.91 |
-85:41:50.2 |
HIP 3470 |
15.73 |
| 2026-06-15 00:00 |
00:54:12.48 |
-85:42:46.5 |
HIP 3470 |
15.23 |
| 2026-06-15 12:00 |
00:54:26.78 |
-85:43:43.0 |
HIP 3470 |
14.76 |
| 2026-06-16 00:00 |
00:54:40.80 |
-85:44:39.6 |
HIP 3470 |
14.34 |
| 2026-06-16 12:00 |
00:54:54.55 |
-85:45:36.4 |
HIP 3470 |
13.96 |
| 2026-06-17 00:00 |
00:55:08.01 |
-85:46:33.3 |
HIP 3470 |
13.64 |
| 2026-06-17 12:00 |
00:55:21.18 |
-85:47:30.3 |
HIP 3470 |
13.38 |
| 2026-06-18 00:00 |
00:55:34.07 |
-85:48:27.5 |
HIP 3470 |
13.17 |
| 2026-06-18 12:00 |
00:55:46.65 |
-85:49:24.8 |
HIP 3470 |
13.03 |
| 2026-06-19 00:00 |
00:55:58.94 |
-85:50:22.2 |
HIP 3470 |
12.96 |
| 2026-06-19 12:00 |
00:56:10.93 |
-85:51:19.8 |
HIP 3470 |
12.95 |
| 2026-06-20 00:00 |
00:56:22.60 |
-85:52:17.5 |
HIP 3470 |
13.01 |
| 2026-06-20 12:00 |
00:56:33.97 |
-85:53:15.3 |
HIP 3470 |
13.13 |
| 2026-06-21 00:00 |
00:56:45.02 |
-85:54:13.2 |
HIP 3470 |
13.32 |
| 2026-06-21 12:00 |
00:56:55.76 |
-85:55:11.2 |
HIP 3470 |
13.57 |
| 2026-06-22 00:00 |
00:57:06.16 |
-85:56:09.4 |
HIP 3470 |
13.88 |