メタデータ
| 項目 |
値 |
| Designation |
C/2017 Y2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-11-04T13:33:04.429440Z |
| Orbit solution date (soln_date, UTC) |
2024-02-25T22:12:25Z |
| Obs used |
961 |
| NEO |
- |
| M1 |
8.600 |
| K1 |
8.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-09-02.0000000 |
| e |
1.00096403 |
| q (au) |
4.632068 |
| a (au) |
-4804.896119 |
| i (deg) |
128.421418 |
| Ω (om, deg) |
65.986420 |
| ω (w, deg) |
147.860404 |
| M (ma, deg) |
-0.000188 |
等級
散乱 + 全体線形
$$
M_a = (8.196 + 3.722\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.196 |
| n |
3.722 |
| gf |
0.956 |
| gb |
-0.841 |
| k |
0.994 |
| δ90 |
9.998 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2017-12-24 |
2020-10-30 |
+1.7402 |
-1.104 |
| 2020-11-05 |
2022-02-23 |
-10.1087 |
+6.757 |
| 2022-02-23 |
2022-07-31 |
+14.3389 |
-12.242 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-25 00:00 |
10:01:18.43 |
-40:00:14.4 |
HIP 49095 |
33.20 |
| 2026-09-25 12:00 |
10:01:24.02 |
-40:01:18.6 |
HIP 49095 |
34.31 |
| 2026-09-26 00:00 |
10:01:29.56 |
-40:02:23.2 |
HIP 49343 |
33.51 |
| 2026-09-26 12:00 |
10:01:35.06 |
-40:03:28.3 |
HIP 49343 |
32.60 |
| 2026-09-27 00:00 |
10:01:40.52 |
-40:04:33.9 |
HIP 49343 |
31.75 |
| 2026-09-27 12:00 |
10:01:45.93 |
-40:05:40.0 |
HIP 49343 |
30.97 |
| 2026-09-28 00:00 |
10:01:51.30 |
-40:06:46.5 |
HIP 49343 |
30.25 |
| 2026-09-28 12:00 |
10:01:56.63 |
-40:07:53.5 |
HIP 49343 |
29.60 |
| 2026-09-29 00:00 |
10:02:01.91 |
-40:09:01.0 |
HIP 49219 |
28.47 |
| 2026-09-29 12:00 |
10:02:07.14 |
-40:10:08.9 |
HIP 49219 |
27.09 |
| 2026-09-30 00:00 |
10:02:12.33 |
-40:11:17.3 |
HIP 49219 |
25.72 |
| 2026-09-30 12:00 |
10:02:17.48 |
-40:12:26.2 |
HIP 49219 |
24.36 |
| 2026-10-01 00:00 |
10:02:22.57 |
-40:13:35.5 |
HIP 49219 |
23.01 |
| 2026-10-01 12:00 |
10:02:27.62 |
-40:14:45.2 |
HIP 49219 |
21.68 |
| 2026-10-02 00:00 |
10:02:32.62 |
-40:15:55.4 |
HIP 49219 |
20.37 |
| 2026-10-02 12:00 |
10:02:37.58 |
-40:17:06.0 |
HIP 49219 |
19.08 |
| 2026-10-03 00:00 |
10:02:42.48 |
-40:18:17.0 |
HIP 49219 |
17.81 |
| 2026-10-03 12:00 |
10:02:47.34 |
-40:19:28.5 |
HIP 49219 |
16.59 |
| 2026-10-04 00:00 |
10:02:52.14 |
-40:20:40.4 |
HIP 49219 |
15.40 |
| 2026-10-04 12:00 |
10:02:56.90 |
-40:21:52.7 |
HIP 49219 |
14.27 |
| 2026-10-05 00:00 |
10:03:01.60 |
-40:23:05.4 |
HIP 49219 |
13.20 |
| 2026-10-05 12:00 |
10:03:06.26 |
-40:24:18.6 |
HIP 49219 |
12.21 |
| 2026-10-06 00:00 |
10:03:10.86 |
-40:25:32.1 |
HIP 49219 |
11.34 |
| 2026-10-06 12:00 |
10:03:15.41 |
-40:26:46.1 |
HIP 49219 |
10.59 |
| 2026-10-07 00:00 |
10:03:19.90 |
-40:28:00.4 |
HIP 49219 |
10.00 |
| 2026-10-07 12:00 |
10:03:24.35 |
-40:29:15.1 |
HIP 49219 |
9.60 |
| 2026-10-08 00:00 |
10:03:28.73 |
-40:30:30.3 |
HIP 49219 |
9.42 |
| 2026-10-08 12:00 |
10:03:33.07 |
-40:31:45.8 |
HIP 49219 |
9.46 |
| 2026-10-09 00:00 |
10:03:37.34 |
-40:33:01.6 |
HIP 49219 |
9.72 |
| 2026-10-09 12:00 |
10:03:41.57 |
-40:34:17.9 |
HIP 49219 |
10.19 |
| 2026-10-10 00:00 |
10:03:45.73 |
-40:35:34.5 |
HIP 49219 |
10.84 |
| 2026-10-10 12:00 |
10:03:49.84 |
-40:36:51.5 |
HIP 49219 |
11.63 |
| 2026-10-11 00:00 |
10:03:53.89 |
-40:38:08.8 |
HIP 49219 |
12.55 |
| 2026-10-11 12:00 |
10:03:57.89 |
-40:39:26.5 |
HIP 49219 |
13.56 |
| 2026-10-12 00:00 |
10:04:01.83 |
-40:40:44.5 |
HIP 49219 |
14.64 |
| 2026-10-12 12:00 |
10:04:05.70 |
-40:42:02.9 |
HIP 49219 |
15.79 |
| 2026-10-13 00:00 |
10:04:09.52 |
-40:43:21.6 |
HIP 49219 |
16.98 |
| 2026-10-13 12:00 |
10:04:13.28 |
-40:44:40.6 |
HIP 49219 |
18.21 |
| 2026-10-14 00:00 |
10:04:16.98 |
-40:46:00.0 |
HIP 49219 |
19.47 |
| 2026-10-14 12:00 |
10:04:20.61 |
-40:47:19.6 |
HIP 49470 |
19.35 |
| 2026-10-15 00:00 |
10:04:24.19 |
-40:48:39.6 |
HIP 49470 |
18.41 |
| 2026-10-15 12:00 |
10:04:27.71 |
-40:49:59.8 |
HIP 49470 |
17.56 |
| 2026-10-16 00:00 |
10:04:31.16 |
-40:51:20.4 |
HIP 49470 |
16.81 |