メタデータ
| 項目 |
値 |
| 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 |
オスキュレーティング軌道要素
| 項目 |
値 |
| 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 |
等級
散乱 + 全体線形
$$
M_a = (12.918 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.918 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.509 |
| 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) |
| 2026-03-26 00:00 |
17:30:44.88 |
-30:51:51.6 |
HIP 85531 |
25.91 |
| 2026-03-26 12:00 |
17:30:45.29 |
-30:52:07.8 |
HIP 85531 |
25.96 |
| 2026-03-27 00:00 |
17:30:45.59 |
-30:52:23.9 |
HIP 85531 |
25.99 |
| 2026-03-27 12:00 |
17:30:45.78 |
-30:52:39.9 |
HIP 85531 |
25.99 |
| 2026-03-28 00:00 |
17:30:45.85 |
-30:52:55.8 |
HIP 85531 |
25.97 |
| 2026-03-28 12:00 |
17:30:45.81 |
-30:53:11.7 |
HIP 85531 |
25.94 |
| 2026-03-29 00:00 |
17:30:45.66 |
-30:53:27.4 |
HIP 85531 |
25.88 |
| 2026-03-29 12:00 |
17:30:45.39 |
-30:53:43.0 |
HIP 85531 |
25.80 |
| 2026-03-30 00:00 |
17:30:45.00 |
-30:53:58.5 |
HIP 85531 |
25.69 |
| 2026-03-30 12:00 |
17:30:44.51 |
-30:54:13.9 |
HIP 85531 |
25.57 |
| 2026-03-31 00:00 |
17:30:43.90 |
-30:54:29.2 |
HIP 85531 |
25.42 |
| 2026-03-31 12:00 |
17:30:43.17 |
-30:54:44.4 |
HIP 85531 |
25.25 |
| 2026-04-01 00:00 |
17:30:42.33 |
-30:54:59.5 |
HIP 85531 |
25.06 |
| 2026-04-01 12:00 |
17:30:41.38 |
-30:55:14.4 |
HIP 85531 |
24.85 |
| 2026-04-02 00:00 |
17:30:40.32 |
-30:55:29.3 |
HIP 85531 |
24.62 |
| 2026-04-02 12:00 |
17:30:39.14 |
-30:55:44.0 |
HIP 85531 |
24.36 |
| 2026-04-03 00:00 |
17:30:37.85 |
-30:55:58.6 |
HIP 85531 |
24.08 |
| 2026-04-03 12:00 |
17:30:36.44 |
-30:56:13.1 |
HIP 85531 |
23.78 |
| 2026-04-04 00:00 |
17:30:34.93 |
-30:56:27.5 |
HIP 85531 |
23.46 |
| 2026-04-04 12:00 |
17:30:33.30 |
-30:56:41.8 |
HIP 85531 |
23.12 |
| 2026-04-05 00:00 |
17:30:31.55 |
-30:56:55.9 |
HIP 85531 |
22.75 |
| 2026-04-05 12:00 |
17:30:29.70 |
-30:57:09.9 |
HIP 85531 |
22.37 |
| 2026-04-06 00:00 |
17:30:27.73 |
-30:57:23.8 |
HIP 85531 |
21.96 |
| 2026-04-06 12:00 |
17:30:25.65 |
-30:57:37.5 |
HIP 85531 |
21.53 |
| 2026-04-07 00:00 |
17:30:23.45 |
-30:57:51.1 |
HIP 85531 |
21.08 |
| 2026-04-07 12:00 |
17:30:21.15 |
-30:58:04.5 |
HIP 85531 |
20.61 |
| 2026-04-08 00:00 |
17:30:18.73 |
-30:58:17.9 |
HIP 85531 |
20.12 |
| 2026-04-08 12:00 |
17:30:16.20 |
-30:58:31.1 |
HIP 85531 |
19.61 |
| 2026-04-09 00:00 |
17:30:13.55 |
-30:58:44.1 |
HIP 85531 |
19.08 |
| 2026-04-09 12:00 |
17:30:10.80 |
-30:58:57.0 |
HIP 85531 |
18.53 |
| 2026-04-10 00:00 |
17:30:07.94 |
-30:59:09.7 |
HIP 85531 |
17.96 |
| 2026-04-10 12:00 |
17:30:04.96 |
-30:59:22.3 |
HIP 85531 |
17.38 |
| 2026-04-11 00:00 |
17:30:01.87 |
-30:59:34.8 |
HIP 85531 |
16.77 |
| 2026-04-11 12:00 |
17:29:58.67 |
-30:59:47.1 |
HIP 85531 |
16.15 |
| 2026-04-12 00:00 |
17:29:55.37 |
-30:59:59.2 |
HIP 85531 |
15.52 |
| 2026-04-12 12:00 |
17:29:51.95 |
-31:00:11.2 |
HIP 85531 |
14.87 |
| 2026-04-13 00:00 |
17:29:48.42 |
-31:00:23.0 |
HIP 85531 |
14.21 |
| 2026-04-13 12:00 |
17:29:44.78 |
-31:00:34.7 |
HIP 85531 |
13.53 |
| 2026-04-14 00:00 |
17:29:41.03 |
-31:00:46.2 |
HIP 85531 |
12.85 |
| 2026-04-14 12:00 |
17:29:37.18 |
-31:00:57.5 |
HIP 85531 |
12.17 |
| 2026-04-15 00:00 |
17:29:33.21 |
-31:01:08.7 |
HIP 85531 |
11.49 |
| 2026-04-15 12:00 |
17:29:29.14 |
-31:01:19.7 |
HIP 85531 |
10.81 |
| 2026-04-16 00:00 |
17:29:24.95 |
-31:01:30.5 |
HIP 85531 |
10.14 |