メタデータ
| 項目 |
値 |
| Designation |
C/2017 Y1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-08-31T11:16:29.493120Z |
| Orbit solution date (soln_date, UTC) |
2022-07-06T03:12:22Z |
| Obs used |
92 |
| NEO |
- |
| M1 |
9.300 |
| K1 |
13.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-03-09.0000000 |
| e |
0.99901916 |
| q (au) |
3.718608 |
| a (au) |
3791.251402 |
| i (deg) |
55.240118 |
| Ω (om, deg) |
307.509679 |
| ω (w, deg) |
134.447483 |
| M (ma, deg) |
0.000800 |
等級
散乱 + 全体線形
$$
M_a = (9.514 + 4.991\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.514 |
| n |
4.991 |
| gf |
0.935 |
| gb |
-0.899 |
| k |
0.999 |
| δ90 |
5.121 |
| 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 |
11:16:54.90 |
-60:56:16.1 |
HIP 55114 |
1.17 |
| 2026-03-26 12:00 |
11:16:45.11 |
-60:55:48.2 |
HIP 55114 |
2.21 |
| 2026-03-27 00:00 |
11:16:35.34 |
-60:55:19.6 |
HIP 55114 |
3.42 |
| 2026-03-27 12:00 |
11:16:25.61 |
-60:54:50.3 |
HIP 55114 |
4.66 |
| 2026-03-28 00:00 |
11:16:15.92 |
-60:54:20.4 |
HIP 55114 |
5.91 |
| 2026-03-28 12:00 |
11:16:06.27 |
-60:53:49.8 |
HIP 55114 |
7.18 |
| 2026-03-29 00:00 |
11:15:56.65 |
-60:53:18.6 |
HIP 55114 |
8.44 |
| 2026-03-29 12:00 |
11:15:47.07 |
-60:52:46.7 |
HIP 55114 |
9.71 |
| 2026-03-30 00:00 |
11:15:37.54 |
-60:52:14.2 |
HIP 55114 |
10.98 |
| 2026-03-30 12:00 |
11:15:28.04 |
-60:51:41.0 |
HIP 54944 |
10.98 |
| 2026-03-31 00:00 |
11:15:18.59 |
-60:51:07.2 |
HIP 54944 |
10.18 |
| 2026-03-31 12:00 |
11:15:09.18 |
-60:50:32.7 |
HIP 54944 |
9.48 |
| 2026-04-01 00:00 |
11:14:59.81 |
-60:49:57.6 |
HIP 54944 |
8.90 |
| 2026-04-01 12:00 |
11:14:50.49 |
-60:49:21.9 |
HIP 54944 |
8.46 |
| 2026-04-02 00:00 |
11:14:41.21 |
-60:48:45.6 |
HIP 54944 |
8.20 |
| 2026-04-02 12:00 |
11:14:31.98 |
-60:48:08.6 |
HIP 54944 |
8.12 |
| 2026-04-03 00:00 |
11:14:22.80 |
-60:47:31.1 |
HIP 54944 |
8.23 |
| 2026-04-03 12:00 |
11:14:13.66 |
-60:46:52.9 |
HIP 54944 |
8.52 |
| 2026-04-04 00:00 |
11:14:04.57 |
-60:46:14.1 |
HIP 54944 |
8.98 |
| 2026-04-04 12:00 |
11:13:55.53 |
-60:45:34.7 |
HIP 54944 |
9.58 |
| 2026-04-05 00:00 |
11:13:46.55 |
-60:44:54.7 |
HIP 54944 |
10.30 |
| 2026-04-05 12:00 |
11:13:37.61 |
-60:44:14.1 |
HIP 54944 |
11.11 |
| 2026-04-06 00:00 |
11:13:28.73 |
-60:43:33.0 |
HIP 54944 |
12.00 |
| 2026-04-06 12:00 |
11:13:19.90 |
-60:42:51.2 |
HIP 54944 |
12.95 |
| 2026-04-07 00:00 |
11:13:11.12 |
-60:42:08.9 |
HIP 54668 |
12.81 |
| 2026-04-07 12:00 |
11:13:02.40 |
-60:41:26.0 |
HIP 54668 |
11.69 |
| 2026-04-08 00:00 |
11:12:53.73 |
-60:40:42.5 |
HIP 54668 |
10.61 |
| 2026-04-08 12:00 |
11:12:45.12 |
-60:39:58.4 |
HIP 54668 |
9.58 |
| 2026-04-09 00:00 |
11:12:36.56 |
-60:39:13.8 |
HIP 54668 |
8.63 |
| 2026-04-09 12:00 |
11:12:28.07 |
-60:38:28.7 |
HIP 54668 |
7.79 |
| 2026-04-10 00:00 |
11:12:19.63 |
-60:37:43.0 |
HIP 54668 |
7.10 |
| 2026-04-10 12:00 |
11:12:11.25 |
-60:36:56.7 |
HIP 54668 |
6.59 |
| 2026-04-11 00:00 |
11:12:02.93 |
-60:36:09.9 |
HIP 54668 |
6.31 |
| 2026-04-11 12:00 |
11:11:54.67 |
-60:35:22.6 |
HIP 54668 |
6.31 |
| 2026-04-12 00:00 |
11:11:46.47 |
-60:34:34.7 |
HIP 54668 |
6.57 |
| 2026-04-12 12:00 |
11:11:38.34 |
-60:33:46.3 |
HIP 54668 |
7.06 |
| 2026-04-13 00:00 |
11:11:30.27 |
-60:32:57.4 |
HIP 54668 |
7.75 |
| 2026-04-13 12:00 |
11:11:22.26 |
-60:32:08.0 |
HIP 54668 |
8.59 |
| 2026-04-14 00:00 |
11:11:14.32 |
-60:31:18.0 |
HIP 54668 |
9.53 |
| 2026-04-14 12:00 |
11:11:06.44 |
-60:30:27.6 |
HIP 54668 |
10.55 |
| 2026-04-15 00:00 |
11:10:58.63 |
-60:29:36.7 |
HIP 54668 |
11.63 |
| 2026-04-15 12:00 |
11:10:50.88 |
-60:28:45.2 |
HIP 54684 |
11.81 |
| 2026-04-16 00:00 |
11:10:43.21 |
-60:27:53.3 |
HIP 54684 |
11.63 |