C/2019 Y4 (ATLAS)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2019 Y4 (ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2020-05-31T00:23:50.930880Z |
| Orbit solution date (soln_date, UTC) | 2024-01-05T08:08:32Z |
| Obs used | 1259 |
| NEO | - |
| M1 | 8.800 |
| K1 | 18.500 |
| PC | 0.030 |
| Discovery observation (MPC, UTC) | 2019-12-28T14:19:26.457600Z |
| Discovery magnitude (MPC) | 19.63 o |
| Discovery observatory (MPC) | T08 · ATLAS-MLO, Mauna Loa |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2020-02-24.0000000 |
| e | 0.99922493 |
| q (au) | 0.252854 |
| a (au) | 326.234163 |
| i (deg) | 45.380208 |
| Ω (om, deg) | 120.568599 |
| ω (w, deg) | 177.409813 |
| M (ma, deg) | 359.983772 |
等級
散乱 + 全体線形
$$ M_a = (9.707 + 5.130\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 9.707 |
| n | 5.130 |
| gf | 0.800 |
| gb | -0.500 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) | 終了日 (UTC) | a | b |
|---|---|---|---|
| 2019-12-20 | 2020-03-31 | +10.2042 | -3.712 |
| 2020-03-31 | 2020-04-12 | -26.1816 | +3.419 |
| 2020-04-12 | 2020-04-27 | -8.1350 | +0.537 |
| 2020-04-27 | 2020-05-21 | -11.1934 | +1.078 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 07:09:54.49 | +10:16:52.1 | HIP 34474 | 23.47 |
| 2026-02-03 12:00 | 07:09:48.36 | +10:17:16.5 | HIP 34474 | 22.64 |
| 2026-02-04 00:00 | 07:09:42.27 | +10:17:41.0 | HIP 34474 | 21.89 |
| 2026-02-04 12:00 | 07:09:36.21 | +10:18:05.7 | HIP 34474 | 21.24 |
| 2026-02-05 00:00 | 07:09:30.18 | +10:18:30.4 | HIP 34474 | 20.69 |
| 2026-02-05 12:00 | 07:09:24.19 | +10:18:55.2 | HIP 34474 | 20.25 |
| 2026-02-06 00:00 | 07:09:18.24 | +10:19:20.1 | HIP 34474 | 19.93 |
| 2026-02-06 12:00 | 07:09:12.33 | +10:19:45.1 | HIP 34474 | 19.72 |
| 2026-02-07 00:00 | 07:09:06.45 | +10:20:10.2 | HIP 34474 | 19.63 |
| 2026-02-07 12:00 | 07:09:00.61 | +10:20:35.3 | HIP 34474 | 19.65 |
| 2026-02-08 00:00 | 07:08:54.81 | +10:21:00.6 | HIP 34474 | 19.80 |
| 2026-02-08 12:00 | 07:08:49.04 | +10:21:25.9 | HIP 34474 | 20.05 |
| 2026-02-09 00:00 | 07:08:43.32 | +10:21:51.3 | HIP 34474 | 20.42 |
| 2026-02-09 12:00 | 07:08:37.63 | +10:22:16.8 | HIP 34474 | 20.88 |
| 2026-02-10 00:00 | 07:08:31.99 | +10:22:42.3 | HIP 34474 | 21.42 |
| 2026-02-10 12:00 | 07:08:26.38 | +10:23:07.9 | HIP 34474 | 22.06 |
| 2026-02-11 00:00 | 07:08:20.82 | +10:23:33.6 | HIP 34474 | 22.76 |
| 2026-02-11 12:00 | 07:08:15.30 | +10:23:59.4 | HIP 34474 | 23.53 |
| 2026-02-12 00:00 | 07:08:09.82 | +10:24:25.2 | HIP 34474 | 24.36 |
| 2026-02-12 12:00 | 07:08:04.38 | +10:24:51.1 | HIP 34474 | 25.23 |
| 2026-02-13 00:00 | 07:07:58.99 | +10:25:17.0 | HIP 34474 | 26.15 |
| 2026-02-13 12:00 | 07:07:53.64 | +10:25:43.0 | HIP 34272 | 25.66 |
| 2026-02-14 00:00 | 07:07:48.33 | +10:26:09.1 | HIP 34272 | 24.64 |
| 2026-02-14 12:00 | 07:07:43.07 | +10:26:35.2 | HIP 34272 | 23.65 |
| 2026-02-15 00:00 | 07:07:37.85 | +10:27:01.4 | HIP 34272 | 22.72 |
| 2026-02-15 12:00 | 07:07:32.68 | +10:27:27.6 | HIP 34272 | 21.84 |
| 2026-02-16 00:00 | 07:07:27.55 | +10:27:53.8 | HIP 34272 | 21.02 |
| 2026-02-16 12:00 | 07:07:22.47 | +10:28:20.2 | HIP 34272 | 20.26 |
| 2026-02-17 00:00 | 07:07:17.43 | +10:28:46.5 | HIP 34272 | 19.58 |
| 2026-02-17 12:00 | 07:07:12.45 | +10:29:12.9 | HIP 34272 | 18.97 |
| 2026-02-18 00:00 | 07:07:07.50 | +10:29:39.3 | HIP 34272 | 18.44 |
| 2026-02-18 12:00 | 07:07:02.61 | +10:30:05.8 | HIP 34272 | 17.99 |
| 2026-02-19 00:00 | 07:06:57.77 | +10:30:32.3 | HIP 34272 | 17.64 |
| 2026-02-19 12:00 | 07:06:52.97 | +10:30:58.9 | HIP 34272 | 17.37 |
| 2026-02-20 00:00 | 07:06:48.22 | +10:31:25.5 | HIP 34272 | 17.20 |
| 2026-02-20 12:00 | 07:06:43.53 | +10:31:52.1 | HIP 34272 | 17.13 |
| 2026-02-21 00:00 | 07:06:38.88 | +10:32:18.7 | HIP 34272 | 17.15 |
| 2026-02-21 12:00 | 07:06:34.28 | +10:32:45.3 | HIP 34272 | 17.26 |
| 2026-02-22 00:00 | 07:06:29.73 | +10:33:12.0 | HIP 34272 | 17.46 |
| 2026-02-22 12:00 | 07:06:25.23 | +10:33:38.7 | HIP 34272 | 17.73 |
| 2026-02-23 00:00 | 07:06:20.79 | +10:34:05.4 | HIP 34272 | 18.09 |
| 2026-02-23 12:00 | 07:06:16.39 | +10:34:32.1 | HIP 34272 | 18.51 |
| 2026-02-24 00:00 | 07:06:12.05 | +10:34:58.9 | HIP 34272 | 18.99 |