メタデータ
| 項目 |
値 |
| 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 · University of Arizona Mt. Lemmon Survey |
オスキュレーティング軌道要素
| 項目 |
値 |
| 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 |
等級
散乱 + 全体線形
$$
M_a = (14.385 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
14.385 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.998 |
| k |
1.000 |
| δ90 |
10.000 |
| パラメータ |
記号 |
範囲 |
説明 |
| 太陽・地球距離が1 AUのときの絶対等級 |
H0 |
-5 to 20 |
彗星の固有の明るさ |
| 測光スロープパラメータ |
n |
2 to 6 |
太陽距離に対する明るさ変化率 |
| 前方散乱非対称係数 |
gf |
0.8 to 1 |
前方散乱の強さ |
| 後方散乱非対称係数 |
gb |
-1 to -0.5 |
後方散乱の強さ |
| 分配係数 |
k |
0.8 to 1 |
前方/後方散乱の寄与比 |
| ダスト/ガス明るさ比 |
δ90 |
1 to 10 |
ダスト散乱とガス放射の相対寄与 |
参考: EPSC-DPS2025-160
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
16:05:43.00 |
+22:49:43.1 |
HIP 78916 |
11.62 |
| 2026-09-20 12:00 |
16:05:46.07 |
+22:48:27.9 |
HIP 78916 |
11.38 |
| 2026-09-21 00:00 |
16:05:49.20 |
+22:47:13.0 |
HIP 78916 |
11.31 |
| 2026-09-21 12:00 |
16:05:52.37 |
+22:45:58.3 |
HIP 78916 |
11.41 |
| 2026-09-22 00:00 |
16:05:55.58 |
+22:44:43.7 |
HIP 78916 |
11.68 |
| 2026-09-22 12:00 |
16:05:58.85 |
+22:43:29.4 |
HIP 78916 |
12.11 |
| 2026-09-23 00:00 |
16:06:02.16 |
+22:42:15.2 |
HIP 78916 |
12.68 |
| 2026-09-23 12:00 |
16:06:05.51 |
+22:41:01.2 |
HIP 78916 |
13.38 |
| 2026-09-24 00:00 |
16:06:08.92 |
+22:39:47.4 |
HIP 78916 |
14.19 |
| 2026-09-24 12:00 |
16:06:12.37 |
+22:38:33.9 |
HIP 78916 |
15.09 |
| 2026-09-25 00:00 |
16:06:15.86 |
+22:37:20.5 |
HIP 78916 |
16.06 |
| 2026-09-25 12:00 |
16:06:19.40 |
+22:36:07.3 |
HIP 78916 |
17.10 |
| 2026-09-26 00:00 |
16:06:22.99 |
+22:34:54.4 |
HIP 78916 |
18.20 |
| 2026-09-26 12:00 |
16:06:26.62 |
+22:33:41.7 |
HIP 78916 |
19.34 |
| 2026-09-27 00:00 |
16:06:30.29 |
+22:32:29.2 |
HIP 78916 |
20.52 |
| 2026-09-27 12:00 |
16:06:34.01 |
+22:31:16.9 |
HIP 78916 |
21.73 |
| 2026-09-28 00:00 |
16:06:37.78 |
+22:30:04.9 |
HIP 78916 |
22.97 |
| 2026-09-28 12:00 |
16:06:41.59 |
+22:28:53.1 |
HIP 78916 |
24.23 |
| 2026-09-29 00:00 |
16:06:45.44 |
+22:27:41.5 |
HIP 78916 |
25.52 |
| 2026-09-29 12:00 |
16:06:49.33 |
+22:26:30.2 |
HIP 78916 |
26.82 |
| 2026-09-30 00:00 |
16:06:53.27 |
+22:25:19.1 |
HIP 78800 |
26.97 |
| 2026-09-30 12:00 |
16:06:57.25 |
+22:24:08.2 |
HIP 79091 |
26.46 |
| 2026-10-01 00:00 |
16:07:01.27 |
+22:22:57.6 |
HIP 79091 |
25.11 |
| 2026-10-01 12:00 |
16:07:05.34 |
+22:21:47.2 |
HIP 79091 |
23.76 |
| 2026-10-02 00:00 |
16:07:09.45 |
+22:20:37.1 |
HIP 79091 |
22.44 |
| 2026-10-02 12:00 |
16:07:13.60 |
+22:19:27.3 |
HIP 79091 |
21.12 |
| 2026-10-03 00:00 |
16:07:17.79 |
+22:18:17.7 |
HIP 79091 |
19.83 |
| 2026-10-03 12:00 |
16:07:22.02 |
+22:17:08.4 |
HIP 79091 |
18.56 |
| 2026-10-04 00:00 |
16:07:26.30 |
+22:15:59.4 |
HIP 79091 |
17.33 |
| 2026-10-04 12:00 |
16:07:30.61 |
+22:14:50.6 |
HIP 79091 |
16.13 |
| 2026-10-05 00:00 |
16:07:34.97 |
+22:13:42.1 |
HIP 79091 |
14.98 |
| 2026-10-05 12:00 |
16:07:39.37 |
+22:12:33.9 |
HIP 79091 |
13.90 |
| 2026-10-06 00:00 |
16:07:43.80 |
+22:11:26.0 |
HIP 79091 |
12.89 |
| 2026-10-06 12:00 |
16:07:48.28 |
+22:10:18.4 |
HIP 79091 |
11.99 |
| 2026-10-07 00:00 |
16:07:52.79 |
+22:09:11.0 |
HIP 79091 |
11.21 |
| 2026-10-07 12:00 |
16:07:57.35 |
+22:08:04.0 |
HIP 79091 |
10.59 |
| 2026-10-08 00:00 |
16:08:01.94 |
+22:06:57.2 |
HIP 79091 |
10.15 |
| 2026-10-08 12:00 |
16:08:06.57 |
+22:05:50.8 |
HIP 79091 |
9.93 |
| 2026-10-09 00:00 |
16:08:11.24 |
+22:04:44.6 |
HIP 79091 |
9.93 |
| 2026-10-09 12:00 |
16:08:15.95 |
+22:03:38.8 |
HIP 79091 |
10.16 |
| 2026-10-10 00:00 |
16:08:20.70 |
+22:02:33.3 |
HIP 79091 |
10.60 |
| 2026-10-10 12:00 |
16:08:25.48 |
+22:01:28.1 |
HIP 79091 |
11.23 |
| 2026-10-11 00:00 |
16:08:30.30 |
+22:00:23.2 |
HIP 79091 |
12.03 |