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) |
| 2026-07-29 00:00 |
16:58:46.76 |
-30:12:03.3 |
HIP 83080 |
5.37 |
| 2026-07-29 12:00 |
16:58:41.27 |
-30:11:31.6 |
HIP 83080 |
4.45 |
| 2026-07-30 00:00 |
16:58:35.88 |
-30:10:59.8 |
HIP 83080 |
3.76 |
| 2026-07-30 12:00 |
16:58:30.59 |
-30:10:28.1 |
HIP 83080 |
3.42 |
| 2026-07-31 00:00 |
16:58:25.39 |
-30:09:56.4 |
HIP 83080 |
3.52 |
| 2026-07-31 12:00 |
16:58:20.29 |
-30:09:24.8 |
HIP 83080 |
4.00 |
| 2026-08-01 00:00 |
16:58:15.30 |
-30:08:53.2 |
HIP 83042 |
4.35 |
| 2026-08-01 12:00 |
16:58:10.40 |
-30:08:21.6 |
HIP 83042 |
4.63 |
| 2026-08-02 00:00 |
16:58:05.60 |
-30:07:50.1 |
HIP 83038 |
5.14 |
| 2026-08-02 12:00 |
16:58:00.89 |
-30:07:18.6 |
HIP 83038 |
5.81 |
| 2026-08-03 00:00 |
16:57:56.29 |
-30:06:47.2 |
HIP 83038 |
6.60 |
| 2026-08-03 12:00 |
16:57:51.79 |
-30:06:15.8 |
HIP 83038 |
7.46 |
| 2026-08-04 00:00 |
16:57:47.39 |
-30:05:44.5 |
HIP 83038 |
8.37 |
| 2026-08-04 12:00 |
16:57:43.10 |
-30:05:13.2 |
HIP 83038 |
9.31 |
| 2026-08-05 00:00 |
16:57:38.90 |
-30:04:42.0 |
HIP 83038 |
10.25 |
| 2026-08-05 12:00 |
16:57:34.80 |
-30:04:10.9 |
HIP 83038 |
11.20 |
| 2026-08-06 00:00 |
16:57:30.81 |
-30:03:39.8 |
HIP 83038 |
12.15 |
| 2026-08-06 12:00 |
16:57:26.92 |
-30:03:08.8 |
HIP 83038 |
13.09 |
| 2026-08-07 00:00 |
16:57:23.14 |
-30:02:37.9 |
HIP 83038 |
14.02 |
| 2026-08-07 12:00 |
16:57:19.45 |
-30:02:07.0 |
HIP 83038 |
14.94 |
| 2026-08-08 00:00 |
16:57:15.87 |
-30:01:36.2 |
HIP 83038 |
15.85 |
| 2026-08-08 12:00 |
16:57:12.40 |
-30:01:05.5 |
HIP 83038 |
16.74 |
| 2026-08-09 00:00 |
16:57:09.03 |
-30:00:34.9 |
HIP 83038 |
17.62 |
| 2026-08-09 12:00 |
16:57:05.76 |
-30:00:04.4 |
HIP 83038 |
18.48 |
| 2026-08-10 00:00 |
16:57:02.60 |
-29:59:33.9 |
HIP 83038 |
19.32 |
| 2026-08-10 12:00 |
16:56:59.55 |
-29:59:03.6 |
HIP 83038 |
20.15 |
| 2026-08-11 00:00 |
16:56:56.60 |
-29:58:33.3 |
HIP 83038 |
20.96 |
| 2026-08-11 12:00 |
16:56:53.76 |
-29:58:03.2 |
HIP 83038 |
21.75 |
| 2026-08-12 00:00 |
16:56:51.02 |
-29:57:33.1 |
HIP 83038 |
22.53 |
| 2026-08-12 12:00 |
16:56:48.40 |
-29:57:03.2 |
HIP 83038 |
23.28 |
| 2026-08-13 00:00 |
16:56:45.87 |
-29:56:33.3 |
HIP 83038 |
24.02 |
| 2026-08-13 12:00 |
16:56:43.46 |
-29:56:03.6 |
HIP 83038 |
24.74 |
| 2026-08-14 00:00 |
16:56:41.15 |
-29:55:34.0 |
HIP 83038 |
25.44 |
| 2026-08-14 12:00 |
16:56:38.95 |
-29:55:04.4 |
HIP 83038 |
26.13 |
| 2026-08-15 00:00 |
16:56:36.86 |
-29:54:35.0 |
HIP 83038 |
26.79 |
| 2026-08-15 12:00 |
16:56:34.88 |
-29:54:05.8 |
HIP 83038 |
27.44 |
| 2026-08-16 00:00 |
16:56:33.00 |
-29:53:36.6 |
HIP 83038 |
28.07 |
| 2026-08-16 12:00 |
16:56:31.23 |
-29:53:07.5 |
HIP 83038 |
28.68 |
| 2026-08-17 00:00 |
16:56:29.57 |
-29:52:38.6 |
HIP 83038 |
29.28 |
| 2026-08-17 12:00 |
16:56:28.02 |
-29:52:09.8 |
HIP 83038 |
29.85 |
| 2026-08-18 00:00 |
16:56:26.57 |
-29:51:41.2 |
HIP 83038 |
30.41 |
| 2026-08-18 12:00 |
16:56:25.24 |
-29:51:12.6 |
HIP 83038 |
30.95 |
| 2026-08-19 00:00 |
16:56:24.01 |
-29:50:44.2 |
HIP 83038 |
31.47 |