| Parameter |
Value |
| Designation |
C/2012 E1 (Hill) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-07-04T01:06:25.787520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:04Z |
| Obs used |
98 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
9.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-04-26.0000000 |
| e |
0.99801285 |
| q (au) |
7.502904 |
| a (au) |
3775.710106 |
| i (deg) |
122.542018 |
| Ω (om, deg) |
286.319642 |
| ω (w, deg) |
48.887314 |
| M (ma, deg) |
0.001262 |
Magnitude
Scatter + Global Linear
$$
M_a = (1.132 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
1.132 |
| n |
6.000 |
| gf |
0.988 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
9.999 |
| 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) |
| 2026-03-26 00:00 |
07:41:03.06 |
+32:44:37.5 |
HIP 37326 |
28.02 |
| 2026-03-26 12:00 |
07:41:00.99 |
+32:44:22.6 |
HIP 37326 |
27.57 |
| 2026-03-27 00:00 |
07:40:58.97 |
+32:44:07.5 |
HIP 37326 |
27.12 |
| 2026-03-27 12:00 |
07:40:56.98 |
+32:43:52.3 |
HIP 37326 |
26.67 |
| 2026-03-28 00:00 |
07:40:55.04 |
+32:43:37.0 |
HIP 37326 |
26.23 |
| 2026-03-28 12:00 |
07:40:53.15 |
+32:43:21.6 |
HIP 37326 |
25.80 |
| 2026-03-29 00:00 |
07:40:51.29 |
+32:43:06.1 |
HIP 37326 |
25.36 |
| 2026-03-29 12:00 |
07:40:49.48 |
+32:42:50.4 |
HIP 37326 |
24.94 |
| 2026-03-30 00:00 |
07:40:47.71 |
+32:42:34.7 |
HIP 37326 |
24.52 |
| 2026-03-30 12:00 |
07:40:45.98 |
+32:42:18.9 |
HIP 37326 |
24.10 |
| 2026-03-31 00:00 |
07:40:44.30 |
+32:42:02.9 |
HIP 37326 |
23.69 |
| 2026-03-31 12:00 |
07:40:42.66 |
+32:41:46.9 |
HIP 37326 |
23.28 |
| 2026-04-01 00:00 |
07:40:41.06 |
+32:41:30.8 |
HIP 37326 |
22.87 |
| 2026-04-01 12:00 |
07:40:39.51 |
+32:41:14.5 |
HIP 37326 |
22.47 |
| 2026-04-02 00:00 |
07:40:37.99 |
+32:40:58.2 |
HIP 37326 |
22.08 |
| 2026-04-02 12:00 |
07:40:36.52 |
+32:40:41.7 |
HIP 37326 |
21.69 |
| 2026-04-03 00:00 |
07:40:35.10 |
+32:40:25.2 |
HIP 37326 |
21.30 |
| 2026-04-03 12:00 |
07:40:33.71 |
+32:40:08.6 |
HIP 37326 |
20.91 |
| 2026-04-04 00:00 |
07:40:32.37 |
+32:39:51.8 |
HIP 37326 |
20.53 |
| 2026-04-04 12:00 |
07:40:31.08 |
+32:39:35.0 |
HIP 37326 |
20.16 |
| 2026-04-05 00:00 |
07:40:29.82 |
+32:39:18.1 |
HIP 37326 |
19.78 |
| 2026-04-05 12:00 |
07:40:28.61 |
+32:39:01.1 |
HIP 37326 |
19.41 |
| 2026-04-06 00:00 |
07:40:27.44 |
+32:38:44.0 |
HIP 37326 |
19.05 |
| 2026-04-06 12:00 |
07:40:26.31 |
+32:38:26.8 |
HIP 37326 |
18.68 |
| 2026-04-07 00:00 |
07:40:25.23 |
+32:38:09.5 |
HIP 37326 |
18.32 |
| 2026-04-07 12:00 |
07:40:24.19 |
+32:37:52.2 |
HIP 37326 |
17.96 |
| 2026-04-08 00:00 |
07:40:23.19 |
+32:37:34.7 |
HIP 37326 |
17.61 |
| 2026-04-08 12:00 |
07:40:22.24 |
+32:37:17.2 |
HIP 37326 |
17.26 |
| 2026-04-09 00:00 |
07:40:21.33 |
+32:36:59.5 |
HIP 37326 |
16.91 |
| 2026-04-09 12:00 |
07:40:20.46 |
+32:36:41.8 |
HIP 37326 |
16.56 |
| 2026-04-10 00:00 |
07:40:19.63 |
+32:36:24.0 |
HIP 37326 |
16.22 |
| 2026-04-10 12:00 |
07:40:18.85 |
+32:36:06.1 |
HIP 37326 |
15.88 |
| 2026-04-11 00:00 |
07:40:18.11 |
+32:35:48.2 |
HIP 37326 |
15.54 |
| 2026-04-11 12:00 |
07:40:17.41 |
+32:35:30.1 |
HIP 37326 |
15.21 |
| 2026-04-12 00:00 |
07:40:16.76 |
+32:35:12.0 |
HIP 37326 |
14.87 |
| 2026-04-12 12:00 |
07:40:16.14 |
+32:34:53.8 |
HIP 37326 |
14.55 |
| 2026-04-13 00:00 |
07:40:15.57 |
+32:34:35.5 |
HIP 37326 |
14.22 |
| 2026-04-13 12:00 |
07:40:15.05 |
+32:34:17.2 |
HIP 37326 |
13.90 |
| 2026-04-14 00:00 |
07:40:14.56 |
+32:33:58.7 |
HIP 37326 |
13.58 |
| 2026-04-14 12:00 |
07:40:14.12 |
+32:33:40.2 |
HIP 37326 |
13.26 |
| 2026-04-15 00:00 |
07:40:13.72 |
+32:33:21.6 |
HIP 37326 |
12.95 |
| 2026-04-15 12:00 |
07:40:13.36 |
+32:33:03.0 |
HIP 37326 |
12.63 |
| 2026-04-16 00:00 |
07:40:13.05 |
+32:32:44.2 |
HIP 37326 |
12.33 |