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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 13:56:09.17 | +17:43:54.7 | HIP 67947 | 25.78 |
| 2026-03-26 12:00 | 13:56:02.37 | +17:44:32.8 | HIP 67947 | 24.20 |
| 2026-03-27 00:00 | 13:55:55.54 | +17:45:10.5 | HIP 67947 | 22.64 |
| 2026-03-27 12:00 | 13:55:48.69 | +17:45:47.9 | HIP 67947 | 21.11 |
| 2026-03-28 00:00 | 13:55:41.81 | +17:46:24.9 | HIP 67947 | 19.62 |
| 2026-03-28 12:00 | 13:55:34.90 | +17:47:01.6 | HIP 67947 | 18.17 |
| 2026-03-29 00:00 | 13:55:27.97 | +17:47:38.0 | HIP 67947 | 16.78 |
| 2026-03-29 12:00 | 13:55:21.02 | +17:48:14.0 | HIP 67947 | 15.48 |
| 2026-03-30 00:00 | 13:55:14.04 | +17:48:49.7 | HIP 67947 | 14.27 |
| 2026-03-30 12:00 | 13:55:07.04 | +17:49:25.1 | HIP 67947 | 13.19 |
| 2026-03-31 00:00 | 13:55:00.01 | +17:50:00.0 | HIP 67947 | 12.28 |
| 2026-03-31 12:00 | 13:54:52.97 | +17:50:34.7 | HIP 67947 | 11.58 |
| 2026-04-01 00:00 | 13:54:45.90 | +17:51:08.9 | HIP 67947 | 11.13 |
| 2026-04-01 12:00 | 13:54:38.81 | +17:51:42.8 | HIP 67947 | 10.95 |
| 2026-04-02 00:00 | 13:54:31.70 | +17:52:16.3 | HIP 67947 | 11.07 |
| 2026-04-02 12:00 | 13:54:24.58 | +17:52:49.5 | HIP 67947 | 11.47 |
| 2026-04-03 00:00 | 13:54:17.43 | +17:53:22.2 | HIP 67947 | 12.14 |
| 2026-04-03 12:00 | 13:54:10.26 | +17:53:54.6 | HIP 67947 | 13.02 |
| 2026-04-04 00:00 | 13:54:03.08 | +17:54:26.6 | HIP 67787 | 12.02 |
| 2026-04-04 12:00 | 13:53:55.88 | +17:54:58.2 | HIP 67787 | 10.26 |
| 2026-04-05 00:00 | 13:53:48.66 | +17:55:29.4 | HIP 67787 | 8.51 |
| 2026-04-05 12:00 | 13:53:41.43 | +17:56:00.2 | HIP 67787 | 6.77 |
| 2026-04-06 00:00 | 13:53:34.18 | +17:56:30.6 | HIP 67787 | 5.08 |
| 2026-04-06 12:00 | 13:53:26.92 | +17:57:00.6 | HIP 67787 | 3.48 |
| 2026-04-07 00:00 | 13:53:19.64 | +17:57:30.2 | HIP 67787 | 2.21 |
| 2026-04-07 12:00 | 13:53:12.35 | +17:57:59.4 | HIP 67787 | 2.02 |
| 2026-04-08 00:00 | 13:53:05.04 | +17:58:28.2 | HIP 67787 | 3.13 |
| 2026-04-08 12:00 | 13:52:57.73 | +17:58:56.5 | HIP 67787 | 4.68 |
| 2026-04-09 00:00 | 13:52:50.40 | +17:59:24.5 | HIP 67787 | 6.37 |
| 2026-04-09 12:00 | 13:52:43.06 | +17:59:52.0 | HIP 67719 | 5.12 |
| 2026-04-10 00:00 | 13:52:35.71 | +18:00:19.0 | HIP 67719 | 3.34 |
| 2026-04-10 12:00 | 13:52:28.35 | +18:00:45.7 | HIP 67719 | 1.63 |
| 2026-04-11 00:00 | 13:52:20.98 | +18:01:11.9 | HIP 67719 | 0.80 |
| 2026-04-11 12:00 | 13:52:13.60 | +18:01:37.6 | HIP 67719 | 2.27 |
| 2026-04-12 00:00 | 13:52:06.21 | +18:02:03.0 | HIP 67719 | 4.02 |
| 2026-04-12 12:00 | 13:51:58.82 | +18:02:27.8 | HIP 67719 | 5.80 |
| 2026-04-13 00:00 | 13:51:51.42 | +18:02:52.3 | HIP 67719 | 7.60 |
| 2026-04-13 12:00 | 13:51:44.01 | +18:03:16.2 | HIP 67719 | 9.39 |
| 2026-04-14 00:00 | 13:51:36.60 | +18:03:39.7 | HIP 67719 | 11.19 |
| 2026-04-14 12:00 | 13:51:29.19 | +18:04:02.8 | HIP 67719 | 12.99 |
| 2026-04-15 00:00 | 13:51:21.77 | +18:04:25.4 | HIP 67719 | 14.79 |
| 2026-04-15 12:00 | 13:51:14.34 | +18:04:47.5 | HIP 67719 | 16.59 |
| 2026-04-16 00:00 | 13:51:06.92 | +18:05:09.1 | HIP 67719 | 18.39 |