| Parameter |
Value |
| Designation |
C/2018 V4 (Africano) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-03-01T16:37:36.183360Z |
| Orbit solution date (soln_date, UTC) |
2022-06-20T23:12:32Z |
| Obs used |
159 |
| NEO |
- |
| M1 |
15.700 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-11-04T10:18:31.392000Z |
| Discovery magnitude (MPC) |
19.70 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-11-17.0000000 |
| e |
0.98482835 |
| q (au) |
3.198877 |
| a (au) |
210.845675 |
| i (deg) |
68.998987 |
| Ω (om, deg) |
78.384315 |
| ω (w, deg) |
0.008035 |
| M (ma, deg) |
359.966297 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.385 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.385 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.505 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
16:20:27.16 |
+26:21:46.6 |
HIP 80078 |
15.63 |
| 2026-05-12 12:00 |
16:20:20.30 |
+26:22:03.9 |
HIP 80078 |
16.20 |
| 2026-05-13 00:00 |
16:20:13.43 |
+26:22:20.7 |
HIP 80078 |
16.88 |
| 2026-05-13 12:00 |
16:20:06.53 |
+26:22:36.8 |
HIP 80078 |
17.67 |
| 2026-05-14 00:00 |
16:19:59.62 |
+26:22:52.3 |
HIP 80078 |
18.55 |
| 2026-05-14 12:00 |
16:19:52.70 |
+26:23:07.2 |
HIP 80078 |
19.52 |
| 2026-05-15 00:00 |
16:19:45.77 |
+26:23:21.5 |
HIP 80078 |
20.54 |
| 2026-05-15 12:00 |
16:19:38.82 |
+26:23:35.1 |
HIP 80078 |
21.63 |
| 2026-05-16 00:00 |
16:19:31.86 |
+26:23:48.1 |
HIP 80078 |
22.77 |
| 2026-05-16 12:00 |
16:19:24.88 |
+26:24:00.5 |
HIP 79985 |
23.12 |
| 2026-05-17 00:00 |
16:19:17.90 |
+26:24:12.2 |
HIP 79985 |
23.53 |
| 2026-05-17 12:00 |
16:19:10.90 |
+26:24:23.3 |
HIP 79917 |
23.29 |
| 2026-05-18 00:00 |
16:19:03.90 |
+26:24:33.8 |
HIP 79917 |
23.11 |
| 2026-05-18 12:00 |
16:18:56.88 |
+26:24:43.6 |
HIP 79917 |
23.02 |
| 2026-05-19 00:00 |
16:18:49.86 |
+26:24:52.8 |
HIP 79917 |
23.03 |
| 2026-05-19 12:00 |
16:18:42.83 |
+26:25:01.3 |
HIP 79917 |
23.13 |
| 2026-05-20 00:00 |
16:18:35.79 |
+26:25:09.3 |
HIP 79917 |
23.34 |
| 2026-05-20 12:00 |
16:18:28.75 |
+26:25:16.5 |
HIP 79917 |
23.63 |
| 2026-05-21 00:00 |
16:18:21.70 |
+26:25:23.1 |
HIP 79917 |
24.02 |
| 2026-05-21 12:00 |
16:18:14.64 |
+26:25:29.1 |
HIP 79917 |
24.49 |
| 2026-05-22 00:00 |
16:18:07.59 |
+26:25:34.4 |
HIP 79917 |
25.05 |
| 2026-05-22 12:00 |
16:18:00.52 |
+26:25:39.1 |
HIP 79917 |
25.68 |
| 2026-05-23 00:00 |
16:17:53.46 |
+26:25:43.2 |
HIP 79917 |
26.38 |
| 2026-05-23 12:00 |
16:17:46.39 |
+26:25:46.6 |
HIP 79917 |
27.15 |
| 2026-05-24 00:00 |
16:17:39.32 |
+26:25:49.3 |
HIP 79917 |
27.98 |
| 2026-05-24 12:00 |
16:17:32.24 |
+26:25:51.4 |
HIP 79917 |
28.86 |
| 2026-05-25 00:00 |
16:17:25.17 |
+26:25:52.8 |
HIP 79917 |
29.80 |
| 2026-05-25 12:00 |
16:17:18.10 |
+26:25:53.6 |
HIP 79917 |
30.77 |
| 2026-05-26 00:00 |
16:17:11.03 |
+26:25:53.8 |
HIP 79917 |
31.79 |
| 2026-05-26 12:00 |
16:17:03.96 |
+26:25:53.3 |
HIP 79917 |
32.85 |
| 2026-05-27 00:00 |
16:16:56.89 |
+26:25:52.1 |
HIP 79917 |
33.94 |
| 2026-05-27 12:00 |
16:16:49.82 |
+26:25:50.3 |
HIP 79917 |
35.05 |
| 2026-05-28 00:00 |
16:16:42.75 |
+26:25:47.9 |
HIP 79917 |
36.20 |
| 2026-05-28 12:00 |
16:16:35.69 |
+26:25:44.8 |
HIP 79917 |
37.37 |
| 2026-05-29 00:00 |
16:16:28.64 |
+26:25:41.1 |
HIP 79917 |
38.56 |
| 2026-05-29 12:00 |
16:16:21.58 |
+26:25:36.7 |
HIP 79917 |
39.78 |
| 2026-05-30 00:00 |
16:16:14.54 |
+26:25:31.6 |
HIP 79917 |
41.01 |
| 2026-05-30 12:00 |
16:16:07.50 |
+26:25:26.0 |
HIP 79917 |
42.26 |
| 2026-05-31 00:00 |
16:16:00.46 |
+26:25:19.6 |
HIP 79683 |
41.99 |
| 2026-05-31 12:00 |
16:15:53.43 |
+26:25:12.6 |
HIP 79683 |
41.78 |
| 2026-06-01 00:00 |
16:15:46.41 |
+26:25:05.0 |
HIP 79683 |
41.61 |
| 2026-06-01 12:00 |
16:15:39.40 |
+26:24:56.7 |
HIP 79683 |
41.49 |
| 2026-06-02 00:00 |
16:15:32.40 |
+26:24:47.8 |
HIP 79441 |
40.41 |