385P/Hill
| Parameter |
Value |
| Designation |
385P/Hill |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2010-11-09T10:11:43.048320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:41Z |
| Obs used |
353 |
| NEO |
- |
| M1 |
7.400 |
| K1 |
25.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-08-02T01:14:10.464000Z |
| Discovery magnitude (MPC) |
20.40 T |
| Discovery observatory (MPC) |
461 · University of Szeged, Piszkéstető Stn. (Konkoly) |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-11-22.0000000 |
| e |
0.40226883 |
| q (au) |
2.555233 |
| a (au) |
4.274887 |
| i (deg) |
16.855651 |
| Ω (om, deg) |
357.157345 |
| ω (w, deg) |
44.328792 |
| M (ma, deg) |
82.916702 |
Magnitude
Scatter + Global Linear
$$
M_a = (18.057 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
18.057 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.644 |
| 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) |
| 2026-02-03 00:00 |
17:58:31.85 |
-38:18:49.3 |
HIP 87978 |
8.86 |
| 2026-02-03 12:00 |
17:59:00.71 |
-38:19:42.6 |
HIP 87978 |
12.55 |
| 2026-02-04 00:00 |
17:59:29.49 |
-38:20:36.0 |
HIP 88180 |
12.17 |
| 2026-02-04 12:00 |
17:59:58.19 |
-38:21:29.7 |
HIP 88180 |
6.51 |
| 2026-02-05 00:00 |
18:00:26.80 |
-38:22:23.5 |
HIP 88180 |
1.32 |
| 2026-02-05 12:00 |
18:00:55.33 |
-38:23:17.4 |
HIP 88180 |
5.04 |
| 2026-02-06 00:00 |
18:01:23.78 |
-38:24:11.6 |
HIP 88314 |
10.14 |
| 2026-02-06 12:00 |
18:01:52.13 |
-38:25:05.9 |
HIP 88314 |
5.07 |
| 2026-02-07 00:00 |
18:02:20.40 |
-38:26:00.5 |
HIP 88314 |
3.44 |
| 2026-02-07 12:00 |
18:02:48.58 |
-38:26:55.2 |
HIP 88314 |
7.78 |
| 2026-02-08 00:00 |
18:03:16.67 |
-38:27:50.1 |
HIP 88314 |
13.09 |
| 2026-02-08 12:00 |
18:03:44.67 |
-38:28:45.2 |
HIP 88314 |
18.54 |
| 2026-02-09 00:00 |
18:04:12.58 |
-38:29:40.5 |
HIP 88596 |
15.67 |
| 2026-02-09 12:00 |
18:04:40.39 |
-38:30:36.0 |
HIP 88596 |
11.61 |
| 2026-02-10 00:00 |
18:05:08.11 |
-38:31:31.7 |
HIP 88596 |
9.22 |
| 2026-02-10 12:00 |
18:05:35.74 |
-38:32:27.6 |
HIP 88596 |
9.80 |
| 2026-02-11 00:00 |
18:06:03.26 |
-38:33:23.8 |
HIP 88596 |
12.93 |
| 2026-02-11 12:00 |
18:06:30.69 |
-38:34:20.1 |
HIP 88708 |
11.12 |
| 2026-02-12 00:00 |
18:06:58.02 |
-38:35:16.7 |
HIP 88824 |
11.10 |
| 2026-02-12 12:00 |
18:07:25.25 |
-38:36:13.5 |
HIP 88824 |
6.14 |
| 2026-02-13 00:00 |
18:07:52.38 |
-38:37:10.5 |
HIP 88824 |
3.27 |
| 2026-02-13 12:00 |
18:08:19.40 |
-38:38:07.7 |
HIP 88824 |
6.45 |
| 2026-02-14 00:00 |
18:08:46.33 |
-38:39:05.2 |
HIP 88941 |
6.49 |
| 2026-02-14 12:00 |
18:09:13.14 |
-38:40:02.9 |
HIP 88941 |
3.47 |
| 2026-02-15 00:00 |
18:09:39.85 |
-38:41:00.9 |
HIP 88941 |
6.20 |
| 2026-02-15 12:00 |
18:10:06.45 |
-38:41:59.1 |
HIP 88966 |
8.51 |
| 2026-02-16 00:00 |
18:10:32.95 |
-38:42:57.5 |
HIP 88966 |
12.33 |
| 2026-02-16 12:00 |
18:10:59.33 |
-38:43:56.2 |
HIP 88966 |
16.92 |
| 2026-02-17 00:00 |
18:11:25.60 |
-38:44:55.1 |
HIP 88966 |
21.77 |
| 2026-02-17 12:00 |
18:11:51.76 |
-38:45:54.3 |
HIP 88966 |
26.74 |
| 2026-02-18 00:00 |
18:12:17.81 |
-38:46:53.8 |
HIP 89269 |
24.17 |
| 2026-02-18 12:00 |
18:12:43.74 |
-38:47:53.5 |
HIP 89269 |
22.00 |
| 2026-02-19 00:00 |
18:13:09.55 |
-38:48:53.4 |
HIP 89269 |
20.90 |
| 2026-02-19 12:00 |
18:13:35.25 |
-38:49:53.7 |
HIP 89269 |
21.00 |
| 2026-02-20 00:00 |
18:14:00.83 |
-38:50:54.2 |
HIP 89269 |
22.29 |
| 2026-02-20 12:00 |
18:14:26.29 |
-38:51:55.0 |
HIP 89531 |
20.36 |
| 2026-02-21 00:00 |
18:14:51.62 |
-38:52:56.0 |
HIP 89531 |
16.02 |
| 2026-02-21 12:00 |
18:15:16.84 |
-38:53:57.4 |
HIP 89531 |
12.26 |
| 2026-02-22 00:00 |
18:15:41.93 |
-38:54:59.0 |
HIP 89531 |
9.72 |
| 2026-02-22 12:00 |
18:16:06.90 |
-38:56:00.9 |
HIP 89531 |
9.41 |
| 2026-02-23 00:00 |
18:16:31.74 |
-38:57:03.1 |
HIP 89531 |
11.49 |
| 2026-02-23 12:00 |
18:16:56.46 |
-38:58:05.6 |
HIP 89531 |
14.96 |
| 2026-02-24 00:00 |
18:17:21.05 |
-38:59:08.3 |
HIP 89690 |
10.41 |