| 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) |
| 2026-09-20 00:00 |
13:25:10.54 |
+04:47:46.5 |
HIP 65442 |
24.66 |
| 2026-09-20 12:00 |
13:25:21.62 |
+04:46:32.0 |
HIP 65442 |
24.43 |
| 2026-09-21 00:00 |
13:25:32.73 |
+04:45:17.6 |
HIP 65442 |
24.58 |
| 2026-09-21 12:00 |
13:25:43.88 |
+04:44:03.3 |
HIP 65442 |
25.11 |
| 2026-09-22 00:00 |
13:25:55.05 |
+04:42:49.2 |
HIP 65442 |
26.00 |
| 2026-09-22 12:00 |
13:26:06.25 |
+04:41:35.2 |
HIP 65442 |
27.20 |
| 2026-09-23 00:00 |
13:26:17.48 |
+04:40:21.3 |
HIP 65442 |
28.69 |
| 2026-09-23 12:00 |
13:26:28.74 |
+04:39:07.5 |
HIP 65442 |
30.42 |
| 2026-09-24 00:00 |
13:26:40.03 |
+04:37:53.9 |
HIP 65442 |
32.35 |
| 2026-09-24 12:00 |
13:26:51.34 |
+04:36:40.4 |
HIP 65766 |
33.28 |
| 2026-09-25 00:00 |
13:27:02.69 |
+04:35:27.1 |
HIP 65766 |
30.25 |
| 2026-09-25 12:00 |
13:27:14.05 |
+04:34:13.8 |
HIP 65766 |
27.23 |
| 2026-09-26 00:00 |
13:27:25.45 |
+04:33:00.8 |
HIP 65766 |
24.21 |
| 2026-09-26 12:00 |
13:27:36.87 |
+04:31:47.9 |
HIP 65766 |
21.22 |
| 2026-09-27 00:00 |
13:27:48.31 |
+04:30:35.1 |
HIP 65766 |
18.24 |
| 2026-09-27 12:00 |
13:27:59.78 |
+04:29:22.5 |
HIP 65766 |
15.31 |
| 2026-09-28 00:00 |
13:28:11.27 |
+04:28:10.0 |
HIP 65766 |
12.46 |
| 2026-09-28 12:00 |
13:28:22.79 |
+04:26:57.7 |
HIP 65766 |
9.76 |
| 2026-09-29 00:00 |
13:28:34.33 |
+04:25:45.6 |
HIP 65766 |
7.38 |
| 2026-09-29 12:00 |
13:28:45.89 |
+04:24:33.7 |
HIP 65766 |
5.76 |
| 2026-09-30 00:00 |
13:28:57.48 |
+04:23:21.9 |
HIP 65766 |
5.59 |
| 2026-09-30 12:00 |
13:29:09.09 |
+04:22:10.3 |
HIP 65766 |
6.99 |
| 2026-10-01 00:00 |
13:29:20.72 |
+04:20:58.8 |
HIP 65766 |
9.28 |
| 2026-10-01 12:00 |
13:29:32.37 |
+04:19:47.6 |
HIP 65766 |
11.96 |
| 2026-10-02 00:00 |
13:29:44.04 |
+04:18:36.5 |
HIP 65766 |
14.82 |
| 2026-10-02 12:00 |
13:29:55.73 |
+04:17:25.6 |
HIP 65766 |
17.78 |
| 2026-10-03 00:00 |
13:30:07.44 |
+04:16:14.9 |
HIP 65959 |
19.21 |
| 2026-10-03 12:00 |
13:30:19.17 |
+04:15:04.5 |
HIP 65959 |
16.40 |
| 2026-10-04 00:00 |
13:30:30.92 |
+04:13:54.2 |
HIP 65959 |
13.74 |
| 2026-10-04 12:00 |
13:30:42.68 |
+04:12:44.1 |
HIP 65959 |
11.32 |
| 2026-10-05 00:00 |
13:30:54.47 |
+04:11:34.2 |
HIP 65959 |
9.36 |
| 2026-10-05 12:00 |
13:31:06.27 |
+04:10:24.5 |
HIP 65959 |
8.17 |
| 2026-10-06 00:00 |
13:31:18.09 |
+04:09:15.1 |
HIP 65959 |
8.12 |
| 2026-10-06 12:00 |
13:31:29.92 |
+04:08:05.8 |
HIP 66002 |
7.73 |
| 2026-10-07 00:00 |
13:31:41.77 |
+04:06:56.8 |
HIP 66002 |
6.66 |
| 2026-10-07 12:00 |
13:31:53.63 |
+04:05:48.0 |
HIP 66002 |
7.01 |
| 2026-10-08 00:00 |
13:32:05.51 |
+04:04:39.5 |
HIP 66002 |
8.60 |
| 2026-10-08 12:00 |
13:32:17.41 |
+04:03:31.2 |
HIP 66002 |
10.90 |
| 2026-10-09 00:00 |
13:32:29.31 |
+04:02:23.1 |
HIP 66002 |
13.56 |
| 2026-10-09 12:00 |
13:32:41.23 |
+04:01:15.3 |
HIP 66002 |
16.41 |
| 2026-10-10 00:00 |
13:32:53.16 |
+04:00:07.7 |
HIP 66173 |
14.76 |
| 2026-10-10 12:00 |
13:33:05.10 |
+03:59:00.3 |
HIP 66173 |
11.58 |
| 2026-10-11 00:00 |
13:33:17.06 |
+03:57:53.2 |
HIP 66173 |
8.41 |