| Parameter |
Value |
| Designation |
393P/Spacewatch-Hill |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2009-05-26T09:40:17.238720Z |
| Orbit solution date (soln_date, UTC) |
2024-02-20T23:48:44Z |
| Obs used |
140 |
| NEO |
- |
| M1 |
7.600 |
| K1 |
16.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-09-24T06:56:17.376000Z |
| Discovery magnitude (MPC) |
21.50 r |
| Discovery observatory (MPC) |
807 · Cerro Tololo Observatory, La Serena |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-12-17.0000000 |
| e |
0.11963494 |
| q (au) |
4.202481 |
| a (au) |
4.773566 |
| i (deg) |
16.807080 |
| Ω (om, deg) |
36.411015 |
| ω (w, deg) |
328.592400 |
| M (ma, deg) |
88.321023 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.412 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.412 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.501 |
| k |
1.000 |
| 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 |
14:10:53.92 |
-15:20:32.3 |
HIP 69273 |
8.89 |
| 2026-06-01 12:00 |
14:10:41.76 |
-15:20:13.6 |
HIP 69273 |
8.93 |
| 2026-06-02 00:00 |
14:10:29.75 |
-15:19:55.4 |
HIP 69273 |
9.88 |
| 2026-06-02 12:00 |
14:10:17.89 |
-15:19:37.7 |
HIP 69273 |
11.49 |
| 2026-06-03 00:00 |
14:10:06.18 |
-15:19:20.6 |
HIP 69273 |
13.50 |
| 2026-06-03 12:00 |
14:09:54.63 |
-15:19:04.1 |
HIP 69273 |
15.74 |
| 2026-06-04 00:00 |
14:09:43.24 |
-15:18:48.2 |
HIP 69273 |
18.11 |
| 2026-06-04 12:00 |
14:09:32.01 |
-15:18:32.8 |
HIP 69273 |
20.54 |
| 2026-06-05 00:00 |
14:09:20.93 |
-15:18:18.1 |
HIP 69273 |
23.00 |
| 2026-06-05 12:00 |
14:09:10.01 |
-15:18:03.9 |
HIP 69273 |
25.47 |
| 2026-06-06 00:00 |
14:08:59.26 |
-15:17:50.3 |
HIP 69273 |
27.94 |
| 2026-06-06 12:00 |
14:08:48.67 |
-15:17:37.4 |
HIP 69273 |
30.39 |
| 2026-06-07 00:00 |
14:08:38.24 |
-15:17:25.1 |
HIP 69273 |
32.83 |
| 2026-06-07 12:00 |
14:08:27.98 |
-15:17:13.4 |
HIP 69273 |
35.23 |
| 2026-06-08 00:00 |
14:08:17.88 |
-15:17:02.4 |
HIP 69273 |
37.62 |
| 2026-06-08 12:00 |
14:08:07.95 |
-15:16:52.0 |
HIP 69273 |
39.96 |
| 2026-06-09 00:00 |
14:07:58.19 |
-15:16:42.2 |
HIP 69273 |
42.28 |
| 2026-06-09 12:00 |
14:07:48.60 |
-15:16:33.2 |
HIP 69273 |
44.56 |
| 2026-06-10 00:00 |
14:07:39.18 |
-15:16:24.7 |
HIP 68807 |
43.23 |
| 2026-06-10 12:00 |
14:07:29.93 |
-15:16:17.0 |
HIP 68807 |
41.35 |
| 2026-06-11 00:00 |
14:07:20.85 |
-15:16:10.0 |
HIP 68807 |
39.55 |
| 2026-06-11 12:00 |
14:07:11.95 |
-15:16:03.6 |
HIP 68807 |
37.83 |
| 2026-06-12 00:00 |
14:07:03.23 |
-15:15:58.0 |
HIP 68807 |
36.19 |
| 2026-06-12 12:00 |
14:06:54.68 |
-15:15:53.0 |
HIP 68807 |
34.64 |
| 2026-06-13 00:00 |
14:06:46.30 |
-15:15:48.8 |
HIP 68807 |
33.19 |
| 2026-06-13 12:00 |
14:06:38.11 |
-15:15:45.3 |
HIP 68807 |
31.84 |
| 2026-06-14 00:00 |
14:06:30.09 |
-15:15:42.5 |
HIP 68807 |
30.59 |
| 2026-06-14 12:00 |
14:06:22.26 |
-15:15:40.4 |
HIP 68807 |
29.45 |
| 2026-06-15 00:00 |
14:06:14.60 |
-15:15:39.1 |
HIP 68807 |
28.42 |
| 2026-06-15 12:00 |
14:06:07.13 |
-15:15:38.5 |
HIP 68807 |
27.52 |
| 2026-06-16 00:00 |
14:05:59.84 |
-15:15:38.7 |
HIP 68807 |
26.73 |
| 2026-06-16 12:00 |
14:05:52.73 |
-15:15:39.6 |
HIP 68807 |
26.06 |
| 2026-06-17 00:00 |
14:05:45.81 |
-15:15:41.3 |
HIP 68807 |
25.52 |
| 2026-06-17 12:00 |
14:05:39.07 |
-15:15:43.8 |
HIP 68763 |
24.62 |
| 2026-06-18 00:00 |
14:05:32.51 |
-15:15:47.0 |
HIP 68763 |
23.57 |
| 2026-06-18 12:00 |
14:05:26.14 |
-15:15:51.0 |
HIP 68763 |
22.62 |
| 2026-06-19 00:00 |
14:05:19.96 |
-15:15:55.8 |
HIP 68763 |
21.78 |
| 2026-06-19 12:00 |
14:05:13.96 |
-15:16:01.4 |
HIP 68729 |
20.71 |
| 2026-06-20 00:00 |
14:05:08.15 |
-15:16:07.8 |
HIP 68729 |
19.57 |
| 2026-06-20 12:00 |
14:05:02.53 |
-15:16:14.9 |
HIP 68729 |
18.50 |
| 2026-06-21 00:00 |
14:04:57.09 |
-15:16:22.8 |
HIP 68729 |
17.49 |
| 2026-06-21 12:00 |
14:04:51.85 |
-15:16:31.6 |
HIP 68729 |
16.54 |
| 2026-06-22 00:00 |
14:04:46.78 |
-15:16:41.1 |
HIP 68729 |
15.65 |