| Parameter |
Value |
| Designation |
C/2009 O4 (Hill) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-01-01T06:37:51.360960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:32Z |
| Obs used |
764 |
| NEO |
- |
| M1 |
4.900 |
| K1 |
21.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-09-03.0000000 |
| e |
1.00133631 |
| q (au) |
2.563789 |
| a (au) |
-1918.552115 |
| i (deg) |
95.823277 |
| Ω (om, deg) |
172.936518 |
| ω (w, deg) |
223.731941 |
| M (ma, deg) |
-0.001411 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.078 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.078 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.622 |
| k |
0.800 |
| 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) |
| 2026-06-01 00:00 |
11:42:25.98 |
+14:45:28.2 |
HIP 57068 |
15.30 |
| 2026-06-01 12:00 |
11:42:25.21 |
+14:45:25.5 |
HIP 57068 |
15.18 |
| 2026-06-02 00:00 |
11:42:24.47 |
+14:45:22.7 |
HIP 57068 |
15.05 |
| 2026-06-02 12:00 |
11:42:23.75 |
+14:45:19.7 |
HIP 57068 |
14.93 |
| 2026-06-03 00:00 |
11:42:23.06 |
+14:45:16.5 |
HIP 57068 |
14.81 |
| 2026-06-03 12:00 |
11:42:22.40 |
+14:45:13.1 |
HIP 57068 |
14.69 |
| 2026-06-04 00:00 |
11:42:21.77 |
+14:45:09.5 |
HIP 57068 |
14.57 |
| 2026-06-04 12:00 |
11:42:21.16 |
+14:45:05.8 |
HIP 57068 |
14.45 |
| 2026-06-05 00:00 |
11:42:20.59 |
+14:45:01.8 |
HIP 57068 |
14.34 |
| 2026-06-05 12:00 |
11:42:20.03 |
+14:44:57.7 |
HIP 57068 |
14.22 |
| 2026-06-06 00:00 |
11:42:19.51 |
+14:44:53.4 |
HIP 57068 |
14.10 |
| 2026-06-06 12:00 |
11:42:19.01 |
+14:44:48.9 |
HIP 57068 |
13.99 |
| 2026-06-07 00:00 |
11:42:18.55 |
+14:44:44.2 |
HIP 57068 |
13.87 |
| 2026-06-07 12:00 |
11:42:18.10 |
+14:44:39.4 |
HIP 57068 |
13.76 |
| 2026-06-08 00:00 |
11:42:17.69 |
+14:44:34.4 |
HIP 57068 |
13.64 |
| 2026-06-08 12:00 |
11:42:17.30 |
+14:44:29.2 |
HIP 57068 |
13.53 |
| 2026-06-09 00:00 |
11:42:16.95 |
+14:44:23.8 |
HIP 57068 |
13.41 |
| 2026-06-09 12:00 |
11:42:16.62 |
+14:44:18.3 |
HIP 57068 |
13.29 |
| 2026-06-10 00:00 |
11:42:16.31 |
+14:44:12.5 |
HIP 57068 |
13.18 |
| 2026-06-10 12:00 |
11:42:16.04 |
+14:44:06.6 |
HIP 57068 |
13.06 |
| 2026-06-11 00:00 |
11:42:15.79 |
+14:44:00.5 |
HIP 57068 |
12.95 |
| 2026-06-11 12:00 |
11:42:15.57 |
+14:43:54.3 |
HIP 57068 |
12.83 |
| 2026-06-12 00:00 |
11:42:15.38 |
+14:43:47.8 |
HIP 57068 |
12.71 |
| 2026-06-12 12:00 |
11:42:15.21 |
+14:43:41.2 |
HIP 57068 |
12.60 |
| 2026-06-13 00:00 |
11:42:15.07 |
+14:43:34.5 |
HIP 57068 |
12.48 |
| 2026-06-13 12:00 |
11:42:14.96 |
+14:43:27.5 |
HIP 57068 |
12.36 |
| 2026-06-14 00:00 |
11:42:14.88 |
+14:43:20.4 |
HIP 57068 |
12.24 |
| 2026-06-14 12:00 |
11:42:14.83 |
+14:43:13.1 |
HIP 57068 |
12.13 |
| 2026-06-15 00:00 |
11:42:14.80 |
+14:43:05.7 |
HIP 57068 |
12.01 |
| 2026-06-15 12:00 |
11:42:14.80 |
+14:42:58.1 |
HIP 57068 |
11.89 |
| 2026-06-16 00:00 |
11:42:14.83 |
+14:42:50.3 |
HIP 57068 |
11.77 |
| 2026-06-16 12:00 |
11:42:14.89 |
+14:42:42.3 |
HIP 57068 |
11.66 |
| 2026-06-17 00:00 |
11:42:14.97 |
+14:42:34.2 |
HIP 57068 |
11.54 |
| 2026-06-17 12:00 |
11:42:15.08 |
+14:42:25.9 |
HIP 57068 |
11.42 |
| 2026-06-18 00:00 |
11:42:15.22 |
+14:42:17.5 |
HIP 57068 |
11.31 |
| 2026-06-18 12:00 |
11:42:15.39 |
+14:42:08.9 |
HIP 57068 |
11.19 |
| 2026-06-19 00:00 |
11:42:15.58 |
+14:42:00.1 |
HIP 57068 |
11.08 |
| 2026-06-19 12:00 |
11:42:15.80 |
+14:41:51.2 |
HIP 57068 |
10.97 |
| 2026-06-20 00:00 |
11:42:16.05 |
+14:41:42.1 |
HIP 57068 |
10.86 |
| 2026-06-20 12:00 |
11:42:16.33 |
+14:41:32.9 |
HIP 57068 |
10.75 |
| 2026-06-21 00:00 |
11:42:16.63 |
+14:41:23.5 |
HIP 57068 |
10.64 |
| 2026-06-21 12:00 |
11:42:16.96 |
+14:41:14.0 |
HIP 57068 |
10.54 |
| 2026-06-22 00:00 |
11:42:17.31 |
+14:41:04.3 |
HIP 57068 |
10.44 |