メタデータ
| 項目 |
値 |
| Designation |
C/1917 F1 (Mellish) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1917-04-11T04:12:43.113600Z |
| Orbit solution date (soln_date, UTC) |
2025-09-09T12:42:30Z |
| Obs used |
12 |
| NEO |
Yes |
| M1 |
10.900 |
| K1 |
15.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1917-04-17.0000000 |
| e |
0.99302944 |
| q (au) |
0.190197 |
| a (au) |
27.285690 |
| i (deg) |
32.686283 |
| Ω (om, deg) |
88.675684 |
| ω (w, deg) |
121.313996 |
| M (ma, deg) |
0.040277 |
等級
散乱 + 全体線形
$$
M_a = (9.401 + 5.430\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.401 |
| n |
5.430 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
1.000 |
| 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 |
02:52:56.49 |
-10:32:00.2 |
HIP 13520 |
18.19 |
| 2026-03-26 12:00 |
02:52:58.47 |
-10:31:40.0 |
HIP 13520 |
17.63 |
| 2026-03-27 00:00 |
02:53:00.46 |
-10:31:19.9 |
HIP 13520 |
17.06 |
| 2026-03-27 12:00 |
02:53:02.47 |
-10:30:59.9 |
HIP 13520 |
16.50 |
| 2026-03-28 00:00 |
02:53:04.48 |
-10:30:39.9 |
HIP 13520 |
15.93 |
| 2026-03-28 12:00 |
02:53:06.52 |
-10:30:20.0 |
HIP 13520 |
15.36 |
| 2026-03-29 00:00 |
02:53:08.56 |
-10:30:00.2 |
HIP 13520 |
14.79 |
| 2026-03-29 12:00 |
02:53:10.62 |
-10:29:40.4 |
HIP 13520 |
14.23 |
| 2026-03-30 00:00 |
02:53:12.69 |
-10:29:20.7 |
HIP 13520 |
13.66 |
| 2026-03-30 12:00 |
02:53:14.78 |
-10:29:01.1 |
HIP 13520 |
13.09 |
| 2026-03-31 00:00 |
02:53:16.87 |
-10:28:41.6 |
HIP 13520 |
12.53 |
| 2026-03-31 12:00 |
02:53:18.98 |
-10:28:22.1 |
HIP 13520 |
11.96 |
| 2026-04-01 00:00 |
02:53:21.11 |
-10:28:02.7 |
HIP 13520 |
11.40 |
| 2026-04-01 12:00 |
02:53:23.24 |
-10:27:43.4 |
HIP 13520 |
10.84 |
| 2026-04-02 00:00 |
02:53:25.39 |
-10:27:24.2 |
HIP 13520 |
10.28 |
| 2026-04-02 12:00 |
02:53:27.55 |
-10:27:05.1 |
HIP 13520 |
9.73 |
| 2026-04-03 00:00 |
02:53:29.72 |
-10:26:46.0 |
HIP 13520 |
9.19 |
| 2026-04-03 12:00 |
02:53:31.90 |
-10:26:27.0 |
HIP 13520 |
8.65 |
| 2026-04-04 00:00 |
02:53:34.10 |
-10:26:08.1 |
HIP 13520 |
8.12 |
| 2026-04-04 12:00 |
02:53:36.30 |
-10:25:49.3 |
HIP 13520 |
7.60 |
| 2026-04-05 00:00 |
02:53:38.52 |
-10:25:30.6 |
HIP 13520 |
7.09 |
| 2026-04-05 12:00 |
02:53:40.75 |
-10:25:12.0 |
HIP 13520 |
6.61 |
| 2026-04-06 00:00 |
02:53:42.99 |
-10:24:53.4 |
HIP 13520 |
6.15 |
| 2026-04-06 12:00 |
02:53:45.24 |
-10:24:35.0 |
HIP 13520 |
5.71 |
| 2026-04-07 00:00 |
02:53:47.50 |
-10:24:16.6 |
HIP 13520 |
5.32 |
| 2026-04-07 12:00 |
02:53:49.77 |
-10:23:58.4 |
HIP 13520 |
4.97 |
| 2026-04-08 00:00 |
02:53:52.05 |
-10:23:40.2 |
HIP 13520 |
4.67 |
| 2026-04-08 12:00 |
02:53:54.35 |
-10:23:22.1 |
HIP 13520 |
4.45 |
| 2026-04-09 00:00 |
02:53:56.65 |
-10:23:04.1 |
HIP 13520 |
4.31 |
| 2026-04-09 12:00 |
02:53:58.96 |
-10:22:46.2 |
HIP 13520 |
4.26 |
| 2026-04-10 00:00 |
02:54:01.28 |
-10:22:28.5 |
HIP 13520 |
4.31 |
| 2026-04-10 12:00 |
02:54:03.61 |
-10:22:10.8 |
HIP 13520 |
4.44 |
| 2026-04-11 00:00 |
02:54:05.96 |
-10:21:53.2 |
HIP 13520 |
4.66 |
| 2026-04-11 12:00 |
02:54:08.31 |
-10:21:35.7 |
HIP 13520 |
4.95 |
| 2026-04-12 00:00 |
02:54:10.67 |
-10:21:18.3 |
HIP 13520 |
5.31 |
| 2026-04-12 12:00 |
02:54:13.04 |
-10:21:01.0 |
HIP 13520 |
5.71 |
| 2026-04-13 00:00 |
02:54:15.41 |
-10:20:43.9 |
HIP 13520 |
6.16 |
| 2026-04-13 12:00 |
02:54:17.80 |
-10:20:26.8 |
HIP 13520 |
6.64 |
| 2026-04-14 00:00 |
02:54:20.19 |
-10:20:09.9 |
HIP 13520 |
7.14 |
| 2026-04-14 12:00 |
02:54:22.60 |
-10:19:53.0 |
HIP 13520 |
7.67 |
| 2026-04-15 00:00 |
02:54:25.01 |
-10:19:36.3 |
HIP 13520 |
8.22 |
| 2026-04-15 12:00 |
02:54:27.43 |
-10:19:19.7 |
HIP 13520 |
8.78 |
| 2026-04-16 00:00 |
02:54:29.86 |
-10:19:03.2 |
HIP 13520 |
9.35 |