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 · 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) |
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
$$
M_a = (13.087 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
13.087 |
| n |
2.000 |
| gf |
0.991 |
| gb |
-0.944 |
| k |
1.000 |
| δ90 |
9.528 |
| 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 |
16:58:46.25 |
-29:26:05.3 |
HIP 83258 |
32.65 |
| 2026-09-20 12:00 |
16:58:51.80 |
-29:25:48.1 |
HIP 83258 |
31.70 |
| 2026-09-21 00:00 |
16:58:57.45 |
-29:25:31.2 |
HIP 83258 |
30.75 |
| 2026-09-21 12:00 |
16:59:03.18 |
-29:25:14.4 |
HIP 83258 |
29.80 |
| 2026-09-22 00:00 |
16:59:09.02 |
-29:24:57.8 |
HIP 83258 |
28.86 |
| 2026-09-22 12:00 |
16:59:14.95 |
-29:24:41.3 |
HIP 83258 |
27.93 |
| 2026-09-23 00:00 |
16:59:20.97 |
-29:24:25.1 |
HIP 83258 |
27.01 |
| 2026-09-23 12:00 |
16:59:27.08 |
-29:24:09.1 |
HIP 83258 |
26.11 |
| 2026-09-24 00:00 |
16:59:33.29 |
-29:23:53.2 |
HIP 83258 |
25.24 |
| 2026-09-24 12:00 |
16:59:39.59 |
-29:23:37.5 |
HIP 83258 |
24.39 |
| 2026-09-25 00:00 |
16:59:45.99 |
-29:23:22.1 |
HIP 83258 |
23.58 |
| 2026-09-25 12:00 |
16:59:52.47 |
-29:23:06.8 |
HIP 83258 |
22.81 |
| 2026-09-26 00:00 |
16:59:59.05 |
-29:22:51.7 |
HIP 83258 |
22.10 |
| 2026-09-26 12:00 |
17:00:05.72 |
-29:22:36.7 |
HIP 83258 |
21.44 |
| 2026-09-27 00:00 |
17:00:12.48 |
-29:22:22.0 |
HIP 83258 |
20.86 |
| 2026-09-27 12:00 |
17:00:19.33 |
-29:22:07.5 |
HIP 83258 |
20.36 |
| 2026-09-28 00:00 |
17:00:26.26 |
-29:21:53.1 |
HIP 83258 |
19.94 |
| 2026-09-28 12:00 |
17:00:33.29 |
-29:21:38.9 |
HIP 83258 |
19.63 |
| 2026-09-29 00:00 |
17:00:40.41 |
-29:21:24.9 |
HIP 83258 |
19.43 |
| 2026-09-29 12:00 |
17:00:47.61 |
-29:21:11.1 |
HIP 83258 |
19.35 |
| 2026-09-30 00:00 |
17:00:54.91 |
-29:20:57.5 |
HIP 83258 |
19.40 |
| 2026-09-30 12:00 |
17:01:02.29 |
-29:20:44.1 |
HIP 83258 |
19.57 |
| 2026-10-01 00:00 |
17:01:09.76 |
-29:20:30.8 |
HIP 83258 |
19.87 |
| 2026-10-01 12:00 |
17:01:17.32 |
-29:20:17.7 |
HIP 83258 |
20.30 |
| 2026-10-02 00:00 |
17:01:24.96 |
-29:20:04.8 |
HIP 83258 |
20.86 |
| 2026-10-02 12:00 |
17:01:32.69 |
-29:19:52.1 |
HIP 83258 |
21.54 |
| 2026-10-03 00:00 |
17:01:40.50 |
-29:19:39.6 |
HIP 83280 |
22.25 |
| 2026-10-03 12:00 |
17:01:48.41 |
-29:19:27.2 |
HIP 83378 |
22.52 |
| 2026-10-04 00:00 |
17:01:56.39 |
-29:19:15.0 |
HIP 83378 |
21.73 |
| 2026-10-04 12:00 |
17:02:04.46 |
-29:19:03.0 |
HIP 83378 |
21.05 |
| 2026-10-05 00:00 |
17:02:12.62 |
-29:18:51.2 |
HIP 83378 |
20.50 |
| 2026-10-05 12:00 |
17:02:20.86 |
-29:18:39.6 |
HIP 83378 |
20.09 |
| 2026-10-06 00:00 |
17:02:29.18 |
-29:18:28.1 |
HIP 83378 |
19.85 |
| 2026-10-06 12:00 |
17:02:37.59 |
-29:18:16.8 |
HIP 83378 |
19.78 |
| 2026-10-07 00:00 |
17:02:46.08 |
-29:18:05.7 |
HIP 83378 |
19.88 |
| 2026-10-07 12:00 |
17:02:54.65 |
-29:17:54.8 |
HIP 83378 |
20.17 |
| 2026-10-08 00:00 |
17:03:03.31 |
-29:17:44.0 |
HIP 83378 |
20.64 |
| 2026-10-08 12:00 |
17:03:12.04 |
-29:17:33.4 |
HIP 83378 |
21.27 |
| 2026-10-09 00:00 |
17:03:20.86 |
-29:17:23.0 |
HIP 83378 |
22.07 |
| 2026-10-09 12:00 |
17:03:29.75 |
-29:17:12.8 |
HIP 83378 |
23.01 |
| 2026-10-10 00:00 |
17:03:38.73 |
-29:17:02.7 |
HIP 83378 |
24.09 |
| 2026-10-10 12:00 |
17:03:47.78 |
-29:16:52.8 |
HIP 83378 |
25.29 |
| 2026-10-11 00:00 |
17:03:56.92 |
-29:16:43.0 |
HIP 83378 |
26.60 |