| 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) |
| 2026-05-12 00:00 |
18:42:41.36 |
-42:51:02.4 |
HIP 91654 |
20.50 |
| 2026-05-12 12:00 |
18:42:32.11 |
-42:52:47.5 |
HIP 91654 |
20.79 |
| 2026-05-13 00:00 |
18:42:22.58 |
-42:54:32.3 |
HIP 91654 |
21.33 |
| 2026-05-13 12:00 |
18:42:12.77 |
-42:56:16.8 |
HIP 91654 |
22.11 |
| 2026-05-14 00:00 |
18:42:02.68 |
-42:58:00.9 |
HIP 91654 |
23.11 |
| 2026-05-14 12:00 |
18:41:52.32 |
-42:59:44.6 |
HIP 91654 |
24.32 |
| 2026-05-15 00:00 |
18:41:41.68 |
-43:01:28.0 |
HIP 91572 |
23.58 |
| 2026-05-15 12:00 |
18:41:30.76 |
-43:03:10.9 |
HIP 91572 |
21.02 |
| 2026-05-16 00:00 |
18:41:19.57 |
-43:04:53.4 |
HIP 91572 |
18.46 |
| 2026-05-16 12:00 |
18:41:08.10 |
-43:06:35.5 |
HIP 91572 |
15.92 |
| 2026-05-17 00:00 |
18:40:56.36 |
-43:08:17.1 |
HIP 91572 |
13.42 |
| 2026-05-17 12:00 |
18:40:44.35 |
-43:09:58.2 |
HIP 91572 |
11.02 |
| 2026-05-18 00:00 |
18:40:32.07 |
-43:11:38.8 |
HIP 91572 |
8.84 |
| 2026-05-18 12:00 |
18:40:19.51 |
-43:13:18.9 |
HIP 91572 |
7.12 |
| 2026-05-19 00:00 |
18:40:06.69 |
-43:14:58.4 |
HIP 91572 |
6.29 |
| 2026-05-19 12:00 |
18:39:53.60 |
-43:16:37.3 |
HIP 91494 |
6.42 |
| 2026-05-20 00:00 |
18:39:40.25 |
-43:18:15.7 |
HIP 91494 |
7.17 |
| 2026-05-20 12:00 |
18:39:26.63 |
-43:19:53.4 |
HIP 91494 |
8.88 |
| 2026-05-21 00:00 |
18:39:12.75 |
-43:21:30.5 |
HIP 91494 |
11.14 |
| 2026-05-21 12:00 |
18:38:58.61 |
-43:23:07.0 |
HIP 91494 |
13.70 |
| 2026-05-22 00:00 |
18:38:44.21 |
-43:24:42.8 |
HIP 91309 |
14.08 |
| 2026-05-22 12:00 |
18:38:29.56 |
-43:26:17.9 |
HIP 91309 |
11.08 |
| 2026-05-23 00:00 |
18:38:14.65 |
-43:27:52.3 |
HIP 91309 |
8.11 |
| 2026-05-23 12:00 |
18:37:59.48 |
-43:29:25.9 |
HIP 91309 |
5.29 |
| 2026-05-24 00:00 |
18:37:44.06 |
-43:30:58.9 |
HIP 91309 |
3.15 |
| 2026-05-24 12:00 |
18:37:28.39 |
-43:32:31.0 |
HIP 91309 |
3.50 |
| 2026-05-25 00:00 |
18:37:12.48 |
-43:34:02.4 |
HIP 91309 |
5.97 |
| 2026-05-25 12:00 |
18:36:56.32 |
-43:35:32.9 |
HIP 91309 |
8.98 |
| 2026-05-26 00:00 |
18:36:39.91 |
-43:37:02.6 |
HIP 91309 |
12.16 |
| 2026-05-26 12:00 |
18:36:23.26 |
-43:38:31.5 |
HIP 91309 |
15.43 |
| 2026-05-27 00:00 |
18:36:06.37 |
-43:39:59.5 |
HIP 91309 |
18.75 |
| 2026-05-27 12:00 |
18:35:49.25 |
-43:41:26.6 |
HIP 91309 |
22.13 |
| 2026-05-28 00:00 |
18:35:31.88 |
-43:42:52.8 |
HIP 91309 |
25.54 |
| 2026-05-28 12:00 |
18:35:14.28 |
-43:44:18.1 |
HIP 91293 |
27.73 |
| 2026-05-29 00:00 |
18:34:56.46 |
-43:45:42.5 |
HIP 91293 |
29.58 |
| 2026-05-29 12:00 |
18:34:38.40 |
-43:47:05.9 |
HIP 91293 |
31.76 |
| 2026-05-30 00:00 |
18:34:20.11 |
-43:48:28.2 |
HIP 90842 |
31.66 |
| 2026-05-30 12:00 |
18:34:01.60 |
-43:49:49.6 |
HIP 90782 |
29.79 |
| 2026-05-31 00:00 |
18:33:42.87 |
-43:51:10.0 |
HIP 90782 |
26.39 |
| 2026-05-31 12:00 |
18:33:23.92 |
-43:52:29.3 |
HIP 90782 |
23.03 |
| 2026-06-01 00:00 |
18:33:04.75 |
-43:53:47.6 |
HIP 90782 |
19.75 |
| 2026-06-01 12:00 |
18:32:45.36 |
-43:55:04.8 |
HIP 90782 |
16.59 |
| 2026-06-02 00:00 |
18:32:25.77 |
-43:56:20.8 |
HIP 90782 |
13.68 |