P/2018 Y2 (Africano)
| Parameter |
Value |
| Designation |
P/2018 Y2 (Africano) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-01-02T14:21:44.887680Z |
| Orbit solution date (soln_date, UTC) |
2021-05-31T22:43:01Z |
| Obs used |
81 |
| NEO |
- |
| M1 |
10.900 |
| K1 |
10.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-12-31T07:03:45.792000Z |
| Discovery magnitude (MPC) |
19.20 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-01-11.0000000 |
| e |
0.47934818 |
| q (au) |
3.893253 |
| a (au) |
7.477652 |
| i (deg) |
11.680345 |
| Ω (om, deg) |
297.264911 |
| ω (w, deg) |
162.498617 |
| M (ma, deg) |
0.404964 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.918 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.918 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.509 |
| 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 |
17:20:42.44 |
-30:20:06.1 |
HIP 84806 |
10.68 |
| 2026-02-03 12:00 |
17:20:53.05 |
-30:20:25.7 |
HIP 84806 |
12.54 |
| 2026-02-04 00:00 |
17:21:03.60 |
-30:20:45.3 |
HIP 84806 |
14.51 |
| 2026-02-04 12:00 |
17:21:14.06 |
-30:21:04.9 |
HIP 84982 |
14.89 |
| 2026-02-05 00:00 |
17:21:24.45 |
-30:21:24.6 |
HIP 84982 |
12.96 |
| 2026-02-05 12:00 |
17:21:34.76 |
-30:21:44.2 |
HIP 84982 |
11.16 |
| 2026-02-06 00:00 |
17:21:44.99 |
-30:22:03.8 |
HIP 84982 |
9.56 |
| 2026-02-06 12:00 |
17:21:55.14 |
-30:22:23.4 |
HIP 84982 |
8.26 |
| 2026-02-07 00:00 |
17:22:05.22 |
-30:22:43.0 |
HIP 84982 |
7.41 |
| 2026-02-07 12:00 |
17:22:15.21 |
-30:23:02.7 |
HIP 84982 |
7.16 |
| 2026-02-08 00:00 |
17:22:25.13 |
-30:23:22.3 |
HIP 84982 |
7.54 |
| 2026-02-08 12:00 |
17:22:34.96 |
-30:23:41.9 |
HIP 84982 |
8.47 |
| 2026-02-09 00:00 |
17:22:44.71 |
-30:24:01.5 |
HIP 84982 |
9.77 |
| 2026-02-09 12:00 |
17:22:54.38 |
-30:24:21.1 |
HIP 84982 |
11.31 |
| 2026-02-10 00:00 |
17:23:03.96 |
-30:24:40.7 |
HIP 84982 |
12.99 |
| 2026-02-10 12:00 |
17:23:13.46 |
-30:25:00.3 |
HIP 84982 |
14.76 |
| 2026-02-11 00:00 |
17:23:22.88 |
-30:25:19.8 |
HIP 84982 |
16.59 |
| 2026-02-11 12:00 |
17:23:32.21 |
-30:25:39.4 |
HIP 84982 |
18.44 |
| 2026-02-12 00:00 |
17:23:41.45 |
-30:25:59.0 |
HIP 84982 |
20.31 |
| 2026-02-12 12:00 |
17:23:50.61 |
-30:26:18.5 |
HIP 84982 |
22.19 |
| 2026-02-13 00:00 |
17:23:59.69 |
-30:26:38.1 |
HIP 84982 |
24.07 |
| 2026-02-13 12:00 |
17:24:08.67 |
-30:26:57.7 |
HIP 84982 |
25.95 |
| 2026-02-14 00:00 |
17:24:17.57 |
-30:27:17.2 |
HIP 84982 |
27.82 |
| 2026-02-14 12:00 |
17:24:26.38 |
-30:27:36.7 |
HIP 84982 |
29.67 |
| 2026-02-15 00:00 |
17:24:35.10 |
-30:27:56.3 |
HIP 84982 |
31.52 |
| 2026-02-15 12:00 |
17:24:43.73 |
-30:28:15.8 |
HIP 85281 |
32.68 |
| 2026-02-16 00:00 |
17:24:52.27 |
-30:28:35.3 |
HIP 85281 |
31.83 |
| 2026-02-16 12:00 |
17:25:00.72 |
-30:28:54.8 |
HIP 85281 |
31.06 |
| 2026-02-17 00:00 |
17:25:09.08 |
-30:29:14.2 |
HIP 85281 |
30.40 |
| 2026-02-17 12:00 |
17:25:17.35 |
-30:29:33.7 |
HIP 85281 |
29.83 |
| 2026-02-18 00:00 |
17:25:25.52 |
-30:29:53.2 |
HIP 85281 |
29.37 |
| 2026-02-18 12:00 |
17:25:33.60 |
-30:30:12.6 |
HIP 85281 |
29.01 |
| 2026-02-19 00:00 |
17:25:41.59 |
-30:30:32.0 |
HIP 85281 |
28.75 |
| 2026-02-19 12:00 |
17:25:49.48 |
-30:30:51.5 |
HIP 85281 |
28.59 |
| 2026-02-20 00:00 |
17:25:57.28 |
-30:31:10.9 |
HIP 85281 |
28.54 |
| 2026-02-20 12:00 |
17:26:04.98 |
-30:31:30.3 |
HIP 85281 |
28.58 |
| 2026-02-21 00:00 |
17:26:12.59 |
-30:31:49.6 |
HIP 85281 |
28.71 |
| 2026-02-21 12:00 |
17:26:20.10 |
-30:32:09.0 |
HIP 85281 |
28.94 |
| 2026-02-22 00:00 |
17:26:27.52 |
-30:32:28.3 |
HIP 85281 |
29.24 |
| 2026-02-22 12:00 |
17:26:34.83 |
-30:32:47.6 |
HIP 85281 |
29.62 |
| 2026-02-23 00:00 |
17:26:42.06 |
-30:33:06.9 |
HIP 85281 |
30.08 |
| 2026-02-23 12:00 |
17:26:49.18 |
-30:33:26.2 |
HIP 85281 |
30.59 |
| 2026-02-24 00:00 |
17:26:56.20 |
-30:33:45.5 |
HIP 85281 |
31.17 |