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) |
| 2026-07-29 00:00 |
11:13:09.63 |
-57:06:30.2 |
HIP 54830 |
4.48 |
| 2026-07-29 12:00 |
11:13:17.54 |
-57:06:03.1 |
HIP 54830 |
3.48 |
| 2026-07-30 00:00 |
11:13:25.50 |
-57:05:36.5 |
HIP 54830 |
2.62 |
| 2026-07-30 12:00 |
11:13:33.50 |
-57:05:10.5 |
HIP 54830 |
2.09 |
| 2026-07-31 00:00 |
11:13:41.55 |
-57:04:45.0 |
HIP 54830 |
2.17 |
| 2026-07-31 12:00 |
11:13:49.63 |
-57:04:20.0 |
HIP 54830 |
2.80 |
| 2026-08-01 00:00 |
11:13:57.76 |
-57:03:55.6 |
HIP 54830 |
3.71 |
| 2026-08-01 12:00 |
11:14:05.93 |
-57:03:31.7 |
HIP 54830 |
4.75 |
| 2026-08-02 00:00 |
11:14:14.14 |
-57:03:08.4 |
HIP 54830 |
5.85 |
| 2026-08-02 12:00 |
11:14:22.39 |
-57:02:45.6 |
HIP 54830 |
6.98 |
| 2026-08-03 00:00 |
11:14:30.68 |
-57:02:23.3 |
HIP 54830 |
8.13 |
| 2026-08-03 12:00 |
11:14:39.01 |
-57:02:01.6 |
HIP 54830 |
9.30 |
| 2026-08-04 00:00 |
11:14:47.38 |
-57:01:40.4 |
HIP 54830 |
10.47 |
| 2026-08-04 12:00 |
11:14:55.79 |
-57:01:19.8 |
HIP 54830 |
11.65 |
| 2026-08-05 00:00 |
11:15:04.24 |
-57:00:59.8 |
HIP 54830 |
12.84 |
| 2026-08-05 12:00 |
11:15:12.72 |
-57:00:40.2 |
HIP 54830 |
14.04 |
| 2026-08-06 00:00 |
11:15:21.24 |
-57:00:21.3 |
HIP 54830 |
15.23 |
| 2026-08-06 12:00 |
11:15:29.80 |
-57:00:02.9 |
HIP 54830 |
16.44 |
| 2026-08-07 00:00 |
11:15:38.40 |
-56:59:45.0 |
HIP 54830 |
17.64 |
| 2026-08-07 12:00 |
11:15:47.03 |
-56:59:27.7 |
HIP 54830 |
18.85 |
| 2026-08-08 00:00 |
11:15:55.70 |
-56:59:11.0 |
HIP 54830 |
20.06 |
| 2026-08-08 12:00 |
11:16:04.40 |
-56:58:54.8 |
HIP 54830 |
21.28 |
| 2026-08-09 00:00 |
11:16:13.14 |
-56:58:39.2 |
HIP 54830 |
22.50 |
| 2026-08-09 12:00 |
11:16:21.91 |
-56:58:24.1 |
HIP 55003 |
23.56 |
| 2026-08-10 00:00 |
11:16:30.72 |
-56:58:09.6 |
HIP 55289 |
23.49 |
| 2026-08-10 12:00 |
11:16:39.56 |
-56:57:55.7 |
HIP 55289 |
22.29 |
| 2026-08-11 00:00 |
11:16:48.43 |
-56:57:42.3 |
HIP 55289 |
21.09 |
| 2026-08-11 12:00 |
11:16:57.34 |
-56:57:29.5 |
HIP 55289 |
19.88 |
| 2026-08-12 00:00 |
11:17:06.27 |
-56:57:17.3 |
HIP 55289 |
18.68 |
| 2026-08-12 12:00 |
11:17:15.24 |
-56:57:05.6 |
HIP 55289 |
17.47 |
| 2026-08-13 00:00 |
11:17:24.24 |
-56:56:54.5 |
HIP 55289 |
16.26 |
| 2026-08-13 12:00 |
11:17:33.27 |
-56:56:44.0 |
HIP 55289 |
15.05 |
| 2026-08-14 00:00 |
11:17:42.33 |
-56:56:34.0 |
HIP 55289 |
13.84 |
| 2026-08-14 12:00 |
11:17:51.42 |
-56:56:24.7 |
HIP 55289 |
12.64 |
| 2026-08-15 00:00 |
11:18:00.54 |
-56:56:15.9 |
HIP 55289 |
11.44 |
| 2026-08-15 12:00 |
11:18:09.68 |
-56:56:07.6 |
HIP 55289 |
10.24 |
| 2026-08-16 00:00 |
11:18:18.85 |
-56:56:00.0 |
HIP 55289 |
9.05 |
| 2026-08-16 12:00 |
11:18:28.06 |
-56:55:52.8 |
HIP 55289 |
7.88 |
| 2026-08-17 00:00 |
11:18:37.28 |
-56:55:46.3 |
HIP 55289 |
6.73 |
| 2026-08-17 12:00 |
11:18:46.54 |
-56:55:40.4 |
HIP 55289 |
5.62 |
| 2026-08-18 00:00 |
11:18:55.82 |
-56:55:35.0 |
HIP 55289 |
4.59 |
| 2026-08-18 12:00 |
11:19:05.12 |
-56:55:30.2 |
HIP 55289 |
3.70 |
| 2026-08-19 00:00 |
11:19:14.45 |
-56:55:25.9 |
HIP 55289 |
3.08 |