C/2018 N2 (ASASSN)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2018 N2 (ASASSN) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2019-11-10T23:08:28.780800Z |
| Orbit solution date (soln_date, UTC) | 2022-12-31T16:12:33Z |
| Obs used | 4653 |
| NEO | - |
| M1 | 9.600 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2018-07-07T09:19:02.208000Z |
| Discovery magnitude (MPC) | 16.40 V |
| Discovery observatory (MPC) | W87 · Cerro Tololo-LCO C |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2020-02-26.0000000 |
| e | 1.00018357 |
| q (au) | 3.124659 |
| a (au) | -17021.931787 |
| i (deg) | 77.530043 |
| Ω (om, deg) | 25.257801 |
| ω (w, deg) | 24.397034 |
| M (ma, deg) | 0.000048 |
等級
散乱 + 全体線形
$$ M_a = (8.257 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 8.257 |
| n | 2.000 |
| gf | 1.000 |
| gb | -0.503 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) | 終了日 (UTC) | a | b |
|---|---|---|---|
| 2017-10-27 | 2019-11-10 | -2.4748 | +1.036 |
| 2019-11-11 | 2021-04-20 | +0.5916 | -0.832 |
| 2021-04-20 | 2022-05-28 | +2.9514 | -2.352 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
ファインディングチャート
天体暦
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 13:44:52.97 | +18:12:19.2 | HIP 67157 | 14.80 |
| 2026-05-12 12:00 | 13:44:46.29 | +18:12:13.6 | HIP 67157 | 16.20 |
| 2026-05-13 00:00 | 13:44:39.64 | +18:12:07.5 | HIP 67157 | 17.64 |
| 2026-05-13 12:00 | 13:44:33.02 | +18:12:00.8 | HIP 67157 | 19.10 |
| 2026-05-14 00:00 | 13:44:26.44 | +18:11:53.6 | HIP 67157 | 20.57 |
| 2026-05-14 12:00 | 13:44:19.88 | +18:11:45.9 | HIP 67157 | 22.05 |
| 2026-05-15 00:00 | 13:44:13.35 | +18:11:37.6 | HIP 67157 | 23.53 |
| 2026-05-15 12:00 | 13:44:06.86 | +18:11:28.8 | HIP 67157 | 25.03 |
| 2026-05-16 00:00 | 13:44:00.40 | +18:11:19.4 | HIP 67157 | 26.52 |
| 2026-05-16 12:00 | 13:43:53.97 | +18:11:09.5 | HIP 67157 | 28.02 |
| 2026-05-17 00:00 | 13:43:47.57 | +18:10:59.1 | HIP 67157 | 29.51 |
| 2026-05-17 12:00 | 13:43:41.21 | +18:10:48.2 | HIP 67090 | 30.71 |
| 2026-05-18 00:00 | 13:43:34.89 | +18:10:36.7 | HIP 67090 | 31.56 |
| 2026-05-18 12:00 | 13:43:28.60 | +18:10:24.7 | HIP 66792 | 31.69 |
| 2026-05-19 00:00 | 13:43:22.34 | +18:10:12.2 | HIP 66792 | 30.22 |
| 2026-05-19 12:00 | 13:43:16.12 | +18:09:59.1 | HIP 66792 | 28.75 |
| 2026-05-20 00:00 | 13:43:09.94 | +18:09:45.5 | HIP 66792 | 27.30 |
| 2026-05-20 12:00 | 13:43:03.79 | +18:09:31.4 | HIP 66792 | 25.86 |
| 2026-05-21 00:00 | 13:42:57.69 | +18:09:16.8 | HIP 66792 | 24.42 |
| 2026-05-21 12:00 | 13:42:51.61 | +18:09:01.6 | HIP 66792 | 22.99 |
| 2026-05-22 00:00 | 13:42:45.58 | +18:08:45.9 | HIP 66792 | 21.58 |
| 2026-05-22 12:00 | 13:42:39.59 | +18:08:29.7 | HIP 66792 | 20.17 |
| 2026-05-23 00:00 | 13:42:33.63 | +18:08:13.0 | HIP 66792 | 18.78 |
| 2026-05-23 12:00 | 13:42:27.72 | +18:07:55.8 | HIP 66792 | 17.39 |
| 2026-05-24 00:00 | 13:42:21.84 | +18:07:38.0 | HIP 66792 | 16.02 |
| 2026-05-24 12:00 | 13:42:16.01 | +18:07:19.8 | HIP 66792 | 14.67 |
| 2026-05-25 00:00 | 13:42:10.22 | +18:07:01.0 | HIP 66792 | 13.33 |
| 2026-05-25 12:00 | 13:42:04.46 | +18:06:41.7 | HIP 66792 | 12.01 |
| 2026-05-26 00:00 | 13:41:58.75 | +18:06:21.9 | HIP 66792 | 10.71 |
| 2026-05-26 12:00 | 13:41:53.08 | +18:06:01.6 | HIP 66792 | 9.45 |
| 2026-05-27 00:00 | 13:41:47.45 | +18:05:40.8 | HIP 66792 | 8.23 |
| 2026-05-27 12:00 | 13:41:41.87 | +18:05:19.5 | HIP 66792 | 7.07 |
| 2026-05-28 00:00 | 13:41:36.32 | +18:04:57.7 | HIP 66792 | 6.00 |
| 2026-05-28 12:00 | 13:41:30.82 | +18:04:35.4 | HIP 66792 | 5.07 |
| 2026-05-29 00:00 | 13:41:25.37 | +18:04:12.6 | HIP 66792 | 4.36 |
| 2026-05-29 12:00 | 13:41:19.96 | +18:03:49.3 | HIP 66792 | 3.99 |
| 2026-05-30 00:00 | 13:41:14.59 | +18:03:25.5 | HIP 66792 | 4.04 |
| 2026-05-30 12:00 | 13:41:09.26 | +18:03:01.3 | HIP 66792 | 4.49 |
| 2026-05-31 00:00 | 13:41:03.98 | +18:02:36.5 | HIP 66792 | 5.24 |
| 2026-05-31 12:00 | 13:40:58.75 | +18:02:11.2 | HIP 66792 | 6.17 |
| 2026-06-01 00:00 | 13:40:53.56 | +18:01:45.5 | HIP 66792 | 7.20 |
| 2026-06-01 12:00 | 13:40:48.42 | +18:01:19.3 | HIP 66792 | 8.31 |
| 2026-06-02 00:00 | 13:40:43.32 | +18:00:52.6 | HIP 66792 | 9.44 |