C/2018 V4 (Africano)
| 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) |
| 2026-02-03 00:00 |
16:28:23.71 |
+23:39:40.6 |
HIP 80751 |
13.52 |
| 2026-02-03 12:00 |
16:28:26.98 |
+23:40:28.0 |
HIP 80751 |
12.47 |
| 2026-02-04 00:00 |
16:28:30.20 |
+23:41:15.8 |
HIP 80751 |
11.44 |
| 2026-02-04 12:00 |
16:28:33.36 |
+23:42:04.0 |
HIP 80751 |
10.43 |
| 2026-02-05 00:00 |
16:28:36.46 |
+23:42:52.5 |
HIP 80751 |
9.45 |
| 2026-02-05 12:00 |
16:28:39.51 |
+23:43:41.3 |
HIP 80751 |
8.50 |
| 2026-02-06 00:00 |
16:28:42.50 |
+23:44:30.6 |
HIP 80751 |
7.59 |
| 2026-02-06 12:00 |
16:28:45.43 |
+23:45:20.1 |
HIP 80751 |
6.75 |
| 2026-02-07 00:00 |
16:28:48.31 |
+23:46:10.0 |
HIP 80751 |
5.98 |
| 2026-02-07 12:00 |
16:28:51.13 |
+23:47:00.2 |
HIP 80751 |
5.34 |
| 2026-02-08 00:00 |
16:28:53.89 |
+23:47:50.8 |
HIP 80751 |
4.85 |
| 2026-02-08 12:00 |
16:28:56.60 |
+23:48:41.7 |
HIP 80751 |
4.57 |
| 2026-02-09 00:00 |
16:28:59.24 |
+23:49:32.9 |
HIP 80751 |
4.54 |
| 2026-02-09 12:00 |
16:29:01.83 |
+23:50:24.4 |
HIP 80751 |
4.76 |
| 2026-02-10 00:00 |
16:29:04.36 |
+23:51:16.3 |
HIP 80751 |
5.19 |
| 2026-02-10 12:00 |
16:29:06.82 |
+23:52:08.4 |
HIP 80751 |
5.79 |
| 2026-02-11 00:00 |
16:29:09.23 |
+23:53:00.9 |
HIP 80751 |
6.51 |
| 2026-02-11 12:00 |
16:29:11.58 |
+23:53:53.6 |
HIP 80751 |
7.31 |
| 2026-02-12 00:00 |
16:29:13.87 |
+23:54:46.7 |
HIP 80751 |
8.17 |
| 2026-02-12 12:00 |
16:29:16.10 |
+23:55:40.0 |
HIP 80751 |
9.06 |
| 2026-02-13 00:00 |
16:29:18.27 |
+23:56:33.6 |
HIP 80751 |
9.99 |
| 2026-02-13 12:00 |
16:29:20.38 |
+23:57:27.5 |
HIP 80751 |
10.93 |
| 2026-02-14 00:00 |
16:29:22.43 |
+23:58:21.7 |
HIP 80751 |
11.89 |
| 2026-02-14 12:00 |
16:29:24.42 |
+23:59:16.1 |
HIP 80751 |
12.86 |
| 2026-02-15 00:00 |
16:29:26.35 |
+24:00:10.8 |
HIP 80751 |
13.84 |
| 2026-02-15 12:00 |
16:29:28.21 |
+24:01:05.8 |
HIP 80751 |
14.82 |
| 2026-02-16 00:00 |
16:29:30.02 |
+24:02:01.0 |
HIP 80751 |
15.81 |
| 2026-02-16 12:00 |
16:29:31.76 |
+24:02:56.5 |
HIP 80751 |
16.80 |
| 2026-02-17 00:00 |
16:29:33.44 |
+24:03:52.2 |
HIP 80751 |
17.80 |
| 2026-02-17 12:00 |
16:29:35.06 |
+24:04:48.2 |
HIP 80751 |
18.79 |
| 2026-02-18 00:00 |
16:29:36.62 |
+24:05:44.3 |
HIP 80751 |
19.79 |
| 2026-02-18 12:00 |
16:29:38.11 |
+24:06:40.8 |
HIP 80886 |
19.96 |
| 2026-02-19 00:00 |
16:29:39.54 |
+24:07:37.4 |
HIP 80886 |
20.04 |
| 2026-02-19 12:00 |
16:29:40.91 |
+24:08:34.2 |
HIP 80886 |
20.18 |
| 2026-02-20 00:00 |
16:29:42.22 |
+24:09:31.3 |
HIP 80886 |
20.38 |
| 2026-02-20 12:00 |
16:29:43.46 |
+24:10:28.6 |
HIP 80886 |
20.65 |
| 2026-02-21 00:00 |
16:29:44.64 |
+24:11:26.0 |
HIP 80886 |
20.97 |
| 2026-02-21 12:00 |
16:29:45.76 |
+24:12:23.7 |
HIP 80886 |
21.34 |
| 2026-02-22 00:00 |
16:29:46.82 |
+24:13:21.5 |
HIP 80886 |
21.77 |
| 2026-02-22 12:00 |
16:29:47.81 |
+24:14:19.5 |
HIP 80886 |
22.25 |
| 2026-02-23 00:00 |
16:29:48.74 |
+24:15:17.7 |
HIP 80886 |
22.77 |
| 2026-02-23 12:00 |
16:29:49.60 |
+24:16:16.1 |
HIP 80886 |
23.34 |
| 2026-02-24 00:00 |
16:29:50.40 |
+24:17:14.7 |
HIP 80886 |
23.94 |