| 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) |
| 2026-03-26 00:00 |
16:28:42.25 |
+25:17:17.6 |
HIP 80646 |
11.66 |
| 2026-03-26 12:00 |
16:28:39.22 |
+25:18:15.4 |
HIP 80646 |
11.58 |
| 2026-03-27 00:00 |
16:28:36.12 |
+25:19:13.1 |
HIP 80646 |
11.62 |
| 2026-03-27 12:00 |
16:28:32.97 |
+25:20:10.5 |
HIP 80681 |
11.15 |
| 2026-03-28 00:00 |
16:28:29.76 |
+25:21:07.8 |
HIP 80681 |
10.05 |
| 2026-03-28 12:00 |
16:28:26.49 |
+25:22:04.8 |
HIP 80681 |
8.97 |
| 2026-03-29 00:00 |
16:28:23.16 |
+25:23:01.6 |
HIP 80681 |
7.94 |
| 2026-03-29 12:00 |
16:28:19.78 |
+25:23:58.2 |
HIP 80681 |
6.96 |
| 2026-03-30 00:00 |
16:28:16.33 |
+25:24:54.5 |
HIP 80681 |
6.07 |
| 2026-03-30 12:00 |
16:28:12.84 |
+25:25:50.6 |
HIP 80681 |
5.32 |
| 2026-03-31 00:00 |
16:28:09.28 |
+25:26:46.5 |
HIP 80681 |
4.78 |
| 2026-03-31 12:00 |
16:28:05.67 |
+25:27:42.1 |
HIP 80681 |
4.53 |
| 2026-04-01 00:00 |
16:28:02.00 |
+25:28:37.5 |
HIP 80681 |
4.63 |
| 2026-04-01 12:00 |
16:27:58.28 |
+25:29:32.6 |
HIP 80681 |
5.05 |
| 2026-04-02 00:00 |
16:27:54.50 |
+25:30:27.5 |
HIP 80681 |
5.73 |
| 2026-04-02 12:00 |
16:27:50.67 |
+25:31:22.0 |
HIP 80681 |
6.59 |
| 2026-04-03 00:00 |
16:27:46.78 |
+25:32:16.3 |
HIP 80681 |
7.57 |
| 2026-04-03 12:00 |
16:27:42.83 |
+25:33:10.4 |
HIP 80681 |
8.64 |
| 2026-04-04 00:00 |
16:27:38.84 |
+25:34:04.1 |
HIP 80681 |
9.76 |
| 2026-04-04 12:00 |
16:27:34.79 |
+25:34:57.6 |
HIP 80681 |
10.92 |
| 2026-04-05 00:00 |
16:27:30.68 |
+25:35:50.7 |
HIP 80681 |
12.12 |
| 2026-04-05 12:00 |
16:27:26.52 |
+25:36:43.6 |
HIP 80681 |
13.34 |
| 2026-04-06 00:00 |
16:27:22.31 |
+25:37:36.1 |
HIP 80681 |
14.58 |
| 2026-04-06 12:00 |
16:27:18.04 |
+25:38:28.3 |
HIP 80681 |
15.84 |
| 2026-04-07 00:00 |
16:27:13.73 |
+25:39:20.3 |
HIP 80681 |
17.11 |
| 2026-04-07 12:00 |
16:27:09.36 |
+25:40:11.9 |
HIP 80681 |
18.39 |
| 2026-04-08 00:00 |
16:27:04.94 |
+25:41:03.1 |
HIP 80681 |
19.68 |
| 2026-04-08 12:00 |
16:27:00.46 |
+25:41:54.1 |
HIP 80681 |
20.98 |
| 2026-04-09 00:00 |
16:26:55.94 |
+25:42:44.7 |
HIP 80641 |
20.99 |
| 2026-04-09 12:00 |
16:26:51.37 |
+25:43:34.9 |
HIP 80641 |
21.03 |
| 2026-04-10 00:00 |
16:26:46.74 |
+25:44:24.8 |
HIP 80641 |
21.16 |
| 2026-04-10 12:00 |
16:26:42.07 |
+25:45:14.4 |
HIP 80641 |
21.39 |
| 2026-04-11 00:00 |
16:26:37.34 |
+25:46:03.5 |
HIP 80641 |
21.71 |
| 2026-04-11 12:00 |
16:26:32.57 |
+25:46:52.4 |
HIP 80641 |
22.12 |
| 2026-04-12 00:00 |
16:26:27.75 |
+25:47:40.8 |
HIP 80500 |
22.03 |
| 2026-04-12 12:00 |
16:26:22.87 |
+25:48:28.9 |
HIP 80500 |
20.92 |
| 2026-04-13 00:00 |
16:26:17.96 |
+25:49:16.6 |
HIP 80500 |
19.85 |
| 2026-04-13 12:00 |
16:26:12.99 |
+25:50:03.9 |
HIP 80500 |
18.82 |
| 2026-04-14 00:00 |
16:26:07.97 |
+25:50:50.8 |
HIP 80500 |
17.84 |
| 2026-04-14 12:00 |
16:26:02.91 |
+25:51:37.3 |
HIP 80500 |
16.92 |
| 2026-04-15 00:00 |
16:25:57.80 |
+25:52:23.4 |
HIP 80500 |
16.07 |
| 2026-04-15 12:00 |
16:25:52.65 |
+25:53:09.1 |
HIP 80500 |
15.31 |
| 2026-04-16 00:00 |
16:25:47.45 |
+25:53:54.3 |
HIP 80500 |
14.65 |