| Parameter |
Value |
| Designation |
C/2018 A6 (Gibbs) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-07-14T07:12:03.481920Z |
| Orbit solution date (soln_date, UTC) |
2024-05-30T01:12:17Z |
| Obs used |
915 |
| NEO |
- |
| M1 |
9.700 |
| K1 |
7.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-12-10.0000000 |
| e |
0.80342745 |
| q (au) |
3.017827 |
| a (au) |
15.352231 |
| i (deg) |
76.954875 |
| Ω (om, deg) |
340.386138 |
| ω (w, deg) |
264.536453 |
| M (ma, deg) |
2.436451 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.874 + 3.973\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.874 |
| n |
3.973 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2017-04-03 |
2018-02-13 |
-4.4374 |
+4.270 |
| 2018-02-13 |
2019-07-08 |
+5.4711 |
-3.199 |
| 2019-07-20 |
2020-06-07 |
+11.2381 |
-6.514 |
| 2020-06-07 |
2021-10-03 |
-7.5580 |
+5.191 |
| 2021-10-03 |
2023-10-19 |
-7.6929 |
+5.633 |
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 |
22:32:02.10 |
+39:16:34.4 |
HIP 111167 |
8.99 |
| 2026-06-01 12:00 |
22:32:01.11 |
+39:18:18.6 |
HIP 111167 |
9.34 |
| 2026-06-02 00:00 |
22:32:00.03 |
+39:20:02.6 |
HIP 111167 |
9.97 |
| 2026-06-02 12:00 |
22:31:58.88 |
+39:21:46.3 |
HIP 111167 |
10.83 |
| 2026-06-03 00:00 |
22:31:57.65 |
+39:23:29.8 |
HIP 111167 |
11.88 |
| 2026-06-03 12:00 |
22:31:56.33 |
+39:25:13.0 |
HIP 111167 |
13.06 |
| 2026-06-04 00:00 |
22:31:54.93 |
+39:26:55.9 |
HIP 111155 |
12.75 |
| 2026-06-04 12:00 |
22:31:53.45 |
+39:28:38.6 |
HIP 111155 |
11.31 |
| 2026-06-05 00:00 |
22:31:51.90 |
+39:30:21.0 |
HIP 111155 |
9.97 |
| 2026-06-05 12:00 |
22:31:50.26 |
+39:32:03.1 |
HIP 111155 |
8.75 |
| 2026-06-06 00:00 |
22:31:48.53 |
+39:33:44.9 |
HIP 111155 |
7.71 |
| 2026-06-06 12:00 |
22:31:46.73 |
+39:35:26.4 |
HIP 111155 |
6.94 |
| 2026-06-07 00:00 |
22:31:44.84 |
+39:37:07.6 |
HIP 111155 |
6.53 |
| 2026-06-07 12:00 |
22:31:42.88 |
+39:38:48.5 |
HIP 111155 |
6.55 |
| 2026-06-08 00:00 |
22:31:40.83 |
+39:40:29.1 |
HIP 111155 |
6.99 |
| 2026-06-08 12:00 |
22:31:38.70 |
+39:42:09.4 |
HIP 111180 |
6.76 |
| 2026-06-09 00:00 |
22:31:36.48 |
+39:43:49.3 |
HIP 111180 |
5.09 |
| 2026-06-09 12:00 |
22:31:34.19 |
+39:45:28.9 |
HIP 111180 |
3.46 |
| 2026-06-10 00:00 |
22:31:31.81 |
+39:47:08.2 |
HIP 111180 |
1.98 |
| 2026-06-10 12:00 |
22:31:29.35 |
+39:48:47.1 |
HIP 111180 |
1.29 |
| 2026-06-11 00:00 |
22:31:26.81 |
+39:50:25.7 |
HIP 111180 |
2.30 |
| 2026-06-11 12:00 |
22:31:24.19 |
+39:52:03.9 |
HIP 111180 |
3.83 |
| 2026-06-12 00:00 |
22:31:21.48 |
+39:53:41.7 |
HIP 111180 |
5.47 |
| 2026-06-12 12:00 |
22:31:18.69 |
+39:55:19.2 |
HIP 111180 |
7.14 |
| 2026-06-13 00:00 |
22:31:15.82 |
+39:56:56.3 |
HIP 111180 |
8.82 |
| 2026-06-13 12:00 |
22:31:12.87 |
+39:58:33.0 |
HIP 111157 |
9.84 |
| 2026-06-14 00:00 |
22:31:09.83 |
+40:00:09.3 |
HIP 111157 |
8.24 |
| 2026-06-14 12:00 |
22:31:06.72 |
+40:01:45.2 |
HIP 111157 |
6.70 |
| 2026-06-15 00:00 |
22:31:03.52 |
+40:03:20.7 |
HIP 111157 |
5.28 |
| 2026-06-15 12:00 |
22:31:00.24 |
+40:04:55.8 |
HIP 111157 |
4.09 |
| 2026-06-16 00:00 |
22:30:56.87 |
+40:06:30.4 |
HIP 111157 |
3.39 |
| 2026-06-16 12:00 |
22:30:53.43 |
+40:08:04.7 |
HIP 111157 |
3.49 |
| 2026-06-17 00:00 |
22:30:49.90 |
+40:09:38.5 |
HIP 111157 |
4.33 |
| 2026-06-17 12:00 |
22:30:46.29 |
+40:11:11.8 |
HIP 111106 |
3.25 |
| 2026-06-18 00:00 |
22:30:42.60 |
+40:12:44.8 |
HIP 111106 |
2.52 |
| 2026-06-18 12:00 |
22:30:38.82 |
+40:14:17.2 |
HIP 111106 |
2.80 |
| 2026-06-19 00:00 |
22:30:34.97 |
+40:15:49.2 |
HIP 111106 |
3.88 |
| 2026-06-19 12:00 |
22:30:31.04 |
+40:17:20.8 |
HIP 111106 |
5.29 |
| 2026-06-20 00:00 |
22:30:27.02 |
+40:18:51.8 |
HIP 111106 |
6.82 |
| 2026-06-20 12:00 |
22:30:22.92 |
+40:20:22.4 |
HIP 111106 |
8.42 |
| 2026-06-21 00:00 |
22:30:18.75 |
+40:21:52.6 |
HIP 111106 |
10.04 |
| 2026-06-21 12:00 |
22:30:14.49 |
+40:23:22.2 |
HIP 111106 |
11.68 |
| 2026-06-22 00:00 |
22:30:10.15 |
+40:24:51.3 |
HIP 111106 |
13.33 |