メタデータ
| 項目 |
値 |
| Designation |
C/2017 M4 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-01-18T08:09:45.547200Z |
| Orbit solution date (soln_date, UTC) |
2022-07-31T01:42:28Z |
| Obs used |
3296 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
6.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-06-17.0000000 |
| e |
1.00108487 |
| q (au) |
3.251701 |
| a (au) |
-2997.319774 |
| i (deg) |
105.657087 |
| Ω (om, deg) |
65.868353 |
| ω (w, deg) |
167.652626 |
| M (ma, deg) |
-0.001293 |
等級
散乱 + 全体線形
$$
M_a = (7.294 + 2.998\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
7.294 |
| n |
2.998 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
10.000 |
| 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) |
| 2026-09-20 00:00 |
06:19:42.09 |
-33:50:10.5 |
HIP 29980 |
19.47 |
| 2026-09-20 12:00 |
06:19:42.32 |
-33:51:17.0 |
HIP 29980 |
20.34 |
| 2026-09-21 00:00 |
06:19:42.49 |
-33:52:23.6 |
HIP 30143 |
19.71 |
| 2026-09-21 12:00 |
06:19:42.59 |
-33:53:30.3 |
HIP 30143 |
18.79 |
| 2026-09-22 00:00 |
06:19:42.64 |
-33:54:37.0 |
HIP 30143 |
17.90 |
| 2026-09-22 12:00 |
06:19:42.62 |
-33:55:43.9 |
HIP 30143 |
17.04 |
| 2026-09-23 00:00 |
06:19:42.54 |
-33:56:50.7 |
HIP 30143 |
16.22 |
| 2026-09-23 12:00 |
06:19:42.39 |
-33:57:57.7 |
HIP 30143 |
15.45 |
| 2026-09-24 00:00 |
06:19:42.18 |
-33:59:04.7 |
HIP 30143 |
14.73 |
| 2026-09-24 12:00 |
06:19:41.91 |
-34:00:11.7 |
HIP 30143 |
14.07 |
| 2026-09-25 00:00 |
06:19:41.58 |
-34:01:18.8 |
HIP 30143 |
13.49 |
| 2026-09-25 12:00 |
06:19:41.18 |
-34:02:25.9 |
HIP 30143 |
12.99 |
| 2026-09-26 00:00 |
06:19:40.72 |
-34:03:33.0 |
HIP 30143 |
12.57 |
| 2026-09-26 12:00 |
06:19:40.19 |
-34:04:40.1 |
HIP 30143 |
12.27 |
| 2026-09-27 00:00 |
06:19:39.61 |
-34:05:47.3 |
HIP 30143 |
12.07 |
| 2026-09-27 12:00 |
06:19:38.96 |
-34:06:54.5 |
HIP 30143 |
11.98 |
| 2026-09-28 00:00 |
06:19:38.24 |
-34:08:01.7 |
HIP 30143 |
12.02 |
| 2026-09-28 12:00 |
06:19:37.46 |
-34:09:08.8 |
HIP 30143 |
12.17 |
| 2026-09-29 00:00 |
06:19:36.62 |
-34:10:16.0 |
HIP 30143 |
12.44 |
| 2026-09-29 12:00 |
06:19:35.71 |
-34:11:23.2 |
HIP 30069 |
12.46 |
| 2026-09-30 00:00 |
06:19:34.74 |
-34:12:30.3 |
HIP 30069 |
11.36 |
| 2026-09-30 12:00 |
06:19:33.70 |
-34:13:37.5 |
HIP 30069 |
10.28 |
| 2026-10-01 00:00 |
06:19:32.60 |
-34:14:44.6 |
HIP 30069 |
9.22 |
| 2026-10-01 12:00 |
06:19:31.44 |
-34:15:51.7 |
HIP 30069 |
8.17 |
| 2026-10-02 00:00 |
06:19:30.21 |
-34:16:58.7 |
HIP 30069 |
7.17 |
| 2026-10-02 12:00 |
06:19:28.92 |
-34:18:05.7 |
HIP 30069 |
6.22 |
| 2026-10-03 00:00 |
06:19:27.56 |
-34:19:12.7 |
HIP 30069 |
5.35 |
| 2026-10-03 12:00 |
06:19:26.14 |
-34:20:19.6 |
HIP 30069 |
4.62 |
| 2026-10-04 00:00 |
06:19:24.65 |
-34:21:26.4 |
HIP 30069 |
4.11 |
| 2026-10-04 12:00 |
06:19:23.10 |
-34:22:33.2 |
HIP 30069 |
3.89 |
| 2026-10-05 00:00 |
06:19:21.48 |
-34:23:39.9 |
HIP 30069 |
4.02 |
| 2026-10-05 12:00 |
06:19:19.80 |
-34:24:46.5 |
HIP 30069 |
4.47 |
| 2026-10-06 00:00 |
06:19:18.05 |
-34:25:53.0 |
HIP 30069 |
5.16 |
| 2026-10-06 12:00 |
06:19:16.24 |
-34:26:59.5 |
HIP 30069 |
6.02 |
| 2026-10-07 00:00 |
06:19:14.36 |
-34:28:05.8 |
HIP 30069 |
6.97 |
| 2026-10-07 12:00 |
06:19:12.42 |
-34:29:12.0 |
HIP 30069 |
7.99 |
| 2026-10-08 00:00 |
06:19:10.41 |
-34:30:18.2 |
HIP 30069 |
9.05 |
| 2026-10-08 12:00 |
06:19:08.34 |
-34:31:24.2 |
HIP 30069 |
10.15 |
| 2026-10-09 00:00 |
06:19:06.20 |
-34:32:30.1 |
HIP 30069 |
11.27 |
| 2026-10-09 12:00 |
06:19:04.00 |
-34:33:35.8 |
HIP 30069 |
12.41 |
| 2026-10-10 00:00 |
06:19:01.73 |
-34:34:41.5 |
HIP 30069 |
13.57 |
| 2026-10-10 12:00 |
06:18:59.40 |
-34:35:46.9 |
HIP 30069 |
14.73 |
| 2026-10-11 00:00 |
06:18:57.00 |
-34:36:52.3 |
HIP 30069 |
15.90 |