| 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) |
| 2026-06-01 00:00 |
13:10:03.73 |
+08:07:22.5 |
HIP 64240 |
41.21 |
| 2026-06-01 12:00 |
13:09:58.56 |
+08:07:21.2 |
HIP 64240 |
41.15 |
| 2026-06-02 00:00 |
13:09:53.47 |
+08:07:19.1 |
HIP 64240 |
41.13 |
| 2026-06-02 12:00 |
13:09:48.47 |
+08:07:16.4 |
HIP 64240 |
41.13 |
| 2026-06-03 00:00 |
13:09:43.56 |
+08:07:12.9 |
HIP 64240 |
41.16 |
| 2026-06-03 12:00 |
13:09:38.73 |
+08:07:08.8 |
HIP 64015 |
40.58 |
| 2026-06-04 00:00 |
13:09:33.99 |
+08:07:03.9 |
HIP 64015 |
39.47 |
| 2026-06-04 12:00 |
13:09:29.34 |
+08:06:58.3 |
HIP 64015 |
38.40 |
| 2026-06-05 00:00 |
13:09:24.77 |
+08:06:51.9 |
HIP 64015 |
37.35 |
| 2026-06-05 12:00 |
13:09:20.29 |
+08:06:44.9 |
HIP 64015 |
36.33 |
| 2026-06-06 00:00 |
13:09:15.90 |
+08:06:37.2 |
HIP 64015 |
35.35 |
| 2026-06-06 12:00 |
13:09:11.60 |
+08:06:28.7 |
HIP 64015 |
34.39 |
| 2026-06-07 00:00 |
13:09:07.39 |
+08:06:19.6 |
HIP 64015 |
33.47 |
| 2026-06-07 12:00 |
13:09:03.27 |
+08:06:09.8 |
HIP 64015 |
32.58 |
| 2026-06-08 00:00 |
13:08:59.23 |
+08:05:59.2 |
HIP 64015 |
31.72 |
| 2026-06-08 12:00 |
13:08:55.29 |
+08:05:48.0 |
HIP 64015 |
30.90 |
| 2026-06-09 00:00 |
13:08:51.44 |
+08:05:36.0 |
HIP 64015 |
30.11 |
| 2026-06-09 12:00 |
13:08:47.67 |
+08:05:23.4 |
HIP 64015 |
29.36 |
| 2026-06-10 00:00 |
13:08:44.00 |
+08:05:10.1 |
HIP 64015 |
28.64 |
| 2026-06-10 12:00 |
13:08:40.42 |
+08:04:56.1 |
HIP 64015 |
27.97 |
| 2026-06-11 00:00 |
13:08:36.93 |
+08:04:41.4 |
HIP 64015 |
27.33 |
| 2026-06-11 12:00 |
13:08:33.53 |
+08:04:26.0 |
HIP 64015 |
26.74 |
| 2026-06-12 00:00 |
13:08:30.22 |
+08:04:09.9 |
HIP 64015 |
26.18 |
| 2026-06-12 12:00 |
13:08:27.01 |
+08:03:53.1 |
HIP 64015 |
25.67 |
| 2026-06-13 00:00 |
13:08:23.89 |
+08:03:35.7 |
HIP 64015 |
25.20 |
| 2026-06-13 12:00 |
13:08:20.85 |
+08:03:17.6 |
HIP 64015 |
24.78 |
| 2026-06-14 00:00 |
13:08:17.92 |
+08:02:58.8 |
HIP 64015 |
24.39 |
| 2026-06-14 12:00 |
13:08:15.07 |
+08:02:39.4 |
HIP 64020 |
23.92 |
| 2026-06-15 00:00 |
13:08:12.32 |
+08:02:19.2 |
HIP 64020 |
23.21 |
| 2026-06-15 12:00 |
13:08:09.66 |
+08:01:58.5 |
HIP 64020 |
22.51 |
| 2026-06-16 00:00 |
13:08:07.10 |
+08:01:37.0 |
HIP 64020 |
21.81 |
| 2026-06-16 12:00 |
13:08:04.62 |
+08:01:14.9 |
HIP 64020 |
21.13 |
| 2026-06-17 00:00 |
13:08:02.25 |
+08:00:52.2 |
HIP 64020 |
20.46 |
| 2026-06-17 12:00 |
13:07:59.96 |
+08:00:28.8 |
HIP 64020 |
19.79 |
| 2026-06-18 00:00 |
13:07:57.77 |
+08:00:04.7 |
HIP 64020 |
19.14 |
| 2026-06-18 12:00 |
13:07:55.67 |
+07:59:40.0 |
HIP 64020 |
18.49 |
| 2026-06-19 00:00 |
13:07:53.67 |
+07:59:14.7 |
HIP 64020 |
17.85 |
| 2026-06-19 12:00 |
13:07:51.76 |
+07:58:48.7 |
HIP 64020 |
17.21 |
| 2026-06-20 00:00 |
13:07:49.95 |
+07:58:22.1 |
HIP 64020 |
16.59 |
| 2026-06-20 12:00 |
13:07:48.22 |
+07:57:54.9 |
HIP 64020 |
15.96 |
| 2026-06-21 00:00 |
13:07:46.60 |
+07:57:27.0 |
HIP 64020 |
15.35 |
| 2026-06-21 12:00 |
13:07:45.06 |
+07:56:58.6 |
HIP 64020 |
14.74 |
| 2026-06-22 00:00 |
13:07:43.62 |
+07:56:29.5 |
HIP 64020 |
14.14 |