| Parameter |
Value |
| Designation |
390P/Gibbs |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-03-23T23:00:23.420160Z |
| Orbit solution date (soln_date, UTC) |
2024-03-04T23:13:05Z |
| Obs used |
339 |
| NEO |
- |
| M1 |
12.300 |
| K1 |
10.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-10-21T05:56:28.665600Z |
| Discovery magnitude (MPC) |
18.45 c |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-03-25.0000000 |
| e |
0.70581897 |
| q (au) |
1.709156 |
| a (au) |
5.809877 |
| i (deg) |
18.522010 |
| Ω (om, deg) |
152.717702 |
| ω (w, deg) |
231.735413 |
| M (ma, deg) |
257.247066 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.035 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.035 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.694 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2019-08-08 |
2020-01-21 |
+11.1256 |
-3.908 |
| 2020-09-01 |
2021-03-06 |
+1.2842 |
-0.774 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
13:10:08.67 |
+06:56:40.3 |
HIP 64192 |
12.32 |
| 2026-07-29 12:00 |
13:10:13.83 |
+06:55:36.2 |
HIP 64192 |
13.85 |
| 2026-07-30 00:00 |
13:10:19.07 |
+06:54:31.8 |
HIP 64192 |
15.43 |
| 2026-07-30 12:00 |
13:10:24.38 |
+06:53:27.1 |
HIP 64192 |
17.04 |
| 2026-07-31 00:00 |
13:10:29.77 |
+06:52:22.1 |
HIP 64364 |
15.99 |
| 2026-07-31 12:00 |
13:10:35.24 |
+06:51:16.9 |
HIP 64364 |
14.37 |
| 2026-08-01 00:00 |
13:10:40.79 |
+06:50:11.3 |
HIP 64364 |
12.77 |
| 2026-08-01 12:00 |
13:10:46.41 |
+06:49:05.4 |
HIP 64364 |
11.19 |
| 2026-08-02 00:00 |
13:10:52.10 |
+06:47:59.3 |
HIP 64364 |
9.65 |
| 2026-08-02 12:00 |
13:10:57.87 |
+06:46:52.8 |
HIP 64364 |
8.21 |
| 2026-08-03 00:00 |
13:11:03.72 |
+06:45:46.1 |
HIP 64364 |
6.92 |
| 2026-08-03 12:00 |
13:11:09.64 |
+06:44:39.2 |
HIP 64364 |
5.91 |
| 2026-08-04 00:00 |
13:11:15.63 |
+06:43:31.9 |
HIP 64364 |
5.35 |
| 2026-08-04 12:00 |
13:11:21.70 |
+06:42:24.4 |
HIP 64364 |
5.40 |
| 2026-08-05 00:00 |
13:11:27.84 |
+06:41:16.6 |
HIP 64364 |
6.08 |
| 2026-08-05 12:00 |
13:11:34.05 |
+06:40:08.6 |
HIP 64364 |
7.20 |
| 2026-08-06 00:00 |
13:11:40.34 |
+06:39:00.3 |
HIP 64330 |
8.38 |
| 2026-08-06 12:00 |
13:11:46.70 |
+06:37:51.7 |
HIP 64330 |
9.74 |
| 2026-08-07 00:00 |
13:11:53.13 |
+06:36:42.9 |
HIP 64330 |
11.30 |
| 2026-08-07 12:00 |
13:11:59.63 |
+06:35:33.9 |
HIP 64330 |
12.99 |
| 2026-08-08 00:00 |
13:12:06.20 |
+06:34:24.6 |
HIP 64330 |
14.76 |
| 2026-08-08 12:00 |
13:12:12.85 |
+06:33:15.1 |
HIP 64330 |
16.61 |
| 2026-08-09 00:00 |
13:12:19.57 |
+06:32:05.3 |
HIP 64330 |
18.51 |
| 2026-08-09 12:00 |
13:12:26.35 |
+06:30:55.4 |
HIP 64330 |
20.46 |
| 2026-08-10 00:00 |
13:12:33.21 |
+06:29:45.2 |
HIP 64330 |
22.44 |
| 2026-08-10 12:00 |
13:12:40.13 |
+06:28:34.7 |
HIP 64330 |
24.45 |
| 2026-08-11 00:00 |
13:12:47.13 |
+06:27:24.1 |
HIP 64330 |
26.49 |
| 2026-08-11 12:00 |
13:12:54.19 |
+06:26:13.3 |
HIP 64330 |
28.56 |
| 2026-08-12 00:00 |
13:13:01.33 |
+06:25:02.2 |
HIP 64330 |
30.65 |
| 2026-08-12 12:00 |
13:13:08.53 |
+06:23:51.0 |
HIP 64330 |
32.76 |
| 2026-08-13 00:00 |
13:13:15.79 |
+06:22:39.5 |
HIP 64330 |
34.89 |
| 2026-08-13 12:00 |
13:13:23.13 |
+06:21:27.9 |
HIP 64330 |
37.04 |
| 2026-08-14 00:00 |
13:13:30.53 |
+06:20:16.1 |
HIP 64330 |
39.22 |
| 2026-08-14 12:00 |
13:13:38.00 |
+06:19:04.1 |
HIP 64330 |
41.41 |
| 2026-08-15 00:00 |
13:13:45.53 |
+06:17:51.9 |
HIP 64768 |
41.27 |
| 2026-08-15 12:00 |
13:13:53.13 |
+06:16:39.5 |
HIP 64768 |
39.87 |
| 2026-08-16 00:00 |
13:14:00.79 |
+06:15:27.0 |
HIP 64768 |
38.54 |
| 2026-08-16 12:00 |
13:14:08.52 |
+06:14:14.3 |
HIP 64768 |
37.28 |
| 2026-08-17 00:00 |
13:14:16.31 |
+06:13:01.4 |
HIP 64768 |
36.11 |
| 2026-08-17 12:00 |
13:14:24.16 |
+06:11:48.4 |
HIP 64768 |
35.03 |
| 2026-08-18 00:00 |
13:14:32.08 |
+06:10:35.3 |
HIP 64768 |
34.07 |
| 2026-08-18 12:00 |
13:14:40.05 |
+06:09:22.0 |
HIP 64768 |
33.23 |
| 2026-08-19 00:00 |
13:14:48.09 |
+06:08:08.5 |
HIP 64768 |
32.52 |