| 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 |
-0.502 |
| 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) |
| 2026-05-12 00:00 |
22:31:37.16 |
+38:04:51.7 |
HIP 111168 |
5.12 |
| 2026-05-12 12:00 |
22:31:39.27 |
+38:06:41.0 |
HIP 111168 |
6.68 |
| 2026-05-13 00:00 |
22:31:41.31 |
+38:08:30.2 |
HIP 111168 |
8.37 |
| 2026-05-13 12:00 |
22:31:43.28 |
+38:10:19.4 |
HIP 111168 |
10.11 |
| 2026-05-14 00:00 |
22:31:45.18 |
+38:12:08.6 |
HIP 111165 |
9.72 |
| 2026-05-14 12:00 |
22:31:47.00 |
+38:13:57.7 |
HIP 111165 |
8.58 |
| 2026-05-15 00:00 |
22:31:48.74 |
+38:15:46.8 |
HIP 111165 |
7.71 |
| 2026-05-15 12:00 |
22:31:50.41 |
+38:17:35.9 |
HIP 111165 |
7.20 |
| 2026-05-16 00:00 |
22:31:52.01 |
+38:19:25.0 |
HIP 111165 |
7.14 |
| 2026-05-16 12:00 |
22:31:53.53 |
+38:21:14.0 |
HIP 111165 |
7.53 |
| 2026-05-17 00:00 |
22:31:54.97 |
+38:23:02.9 |
HIP 111165 |
8.30 |
| 2026-05-17 12:00 |
22:31:56.34 |
+38:24:51.8 |
HIP 111165 |
9.36 |
| 2026-05-18 00:00 |
22:31:57.63 |
+38:26:40.6 |
HIP 111165 |
10.62 |
| 2026-05-18 12:00 |
22:31:58.84 |
+38:28:29.3 |
HIP 111165 |
12.02 |
| 2026-05-19 00:00 |
22:31:59.98 |
+38:30:18.0 |
HIP 111165 |
13.51 |
| 2026-05-19 12:00 |
22:32:01.04 |
+38:32:06.5 |
HIP 111298 |
14.92 |
| 2026-05-20 00:00 |
22:32:02.03 |
+38:33:55.0 |
HIP 111298 |
13.42 |
| 2026-05-20 12:00 |
22:32:02.93 |
+38:35:43.3 |
HIP 111298 |
12.01 |
| 2026-05-21 00:00 |
22:32:03.76 |
+38:37:31.6 |
HIP 111298 |
10.74 |
| 2026-05-21 12:00 |
22:32:04.51 |
+38:39:19.7 |
HIP 111298 |
9.65 |
| 2026-05-22 00:00 |
22:32:05.19 |
+38:41:07.8 |
HIP 111298 |
8.83 |
| 2026-05-22 12:00 |
22:32:05.78 |
+38:42:55.7 |
HIP 111298 |
8.33 |
| 2026-05-23 00:00 |
22:32:06.30 |
+38:44:43.4 |
HIP 111298 |
8.22 |
| 2026-05-23 12:00 |
22:32:06.74 |
+38:46:31.0 |
HIP 111298 |
8.52 |
| 2026-05-24 00:00 |
22:32:07.10 |
+38:48:18.5 |
HIP 111298 |
9.17 |
| 2026-05-24 12:00 |
22:32:07.38 |
+38:50:05.9 |
HIP 111298 |
10.12 |
| 2026-05-25 00:00 |
22:32:07.59 |
+38:51:53.1 |
HIP 111298 |
11.28 |
| 2026-05-25 12:00 |
22:32:07.71 |
+38:53:40.1 |
HIP 111298 |
12.60 |
| 2026-05-26 00:00 |
22:32:07.76 |
+38:55:26.9 |
HIP 111298 |
14.03 |
| 2026-05-26 12:00 |
22:32:07.72 |
+38:57:13.6 |
HIP 111298 |
15.53 |
| 2026-05-27 00:00 |
22:32:07.61 |
+38:59:00.2 |
HIP 111298 |
17.09 |
| 2026-05-27 12:00 |
22:32:07.42 |
+39:00:46.5 |
HIP 111167 |
16.99 |
| 2026-05-28 00:00 |
22:32:07.15 |
+39:02:32.6 |
HIP 111167 |
15.55 |
| 2026-05-28 12:00 |
22:32:06.80 |
+39:04:18.6 |
HIP 111167 |
14.17 |
| 2026-05-29 00:00 |
22:32:06.36 |
+39:06:04.3 |
HIP 111167 |
12.88 |
| 2026-05-29 12:00 |
22:32:05.85 |
+39:07:49.9 |
HIP 111167 |
11.70 |
| 2026-05-30 00:00 |
22:32:05.26 |
+39:09:35.2 |
HIP 111167 |
10.67 |
| 2026-05-30 12:00 |
22:32:04.59 |
+39:11:20.4 |
HIP 111167 |
9.84 |
| 2026-05-31 00:00 |
22:32:03.84 |
+39:13:05.3 |
HIP 111167 |
9.25 |
| 2026-05-31 12:00 |
22:32:03.01 |
+39:14:49.9 |
HIP 111167 |
8.96 |
| 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 |