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 | -2.4742 | +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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 13:36:49.18 | +16:28:26.7 | HIP 66430 | 6.51 |
| 2026-07-29 12:00 | 13:36:50.27 | +16:27:23.1 | HIP 66430 | 5.59 |
| 2026-07-30 00:00 | 13:36:51.41 | +16:26:19.3 | HIP 66430 | 4.73 |
| 2026-07-30 12:00 | 13:36:52.60 | +16:25:15.4 | HIP 66430 | 3.98 |
| 2026-07-31 00:00 | 13:36:53.84 | +16:24:11.4 | HIP 66430 | 3.41 |
| 2026-07-31 12:00 | 13:36:55.13 | +16:23:07.3 | HIP 66430 | 3.13 |
| 2026-08-01 00:00 | 13:36:56.48 | +16:22:03.0 | HIP 66430 | 3.22 |
| 2026-08-01 12:00 | 13:36:57.87 | +16:20:58.7 | HIP 66430 | 3.67 |
| 2026-08-02 00:00 | 13:36:59.32 | +16:19:54.2 | HIP 66430 | 4.36 |
| 2026-08-02 12:00 | 13:37:00.82 | +16:18:49.6 | HIP 66430 | 5.20 |
| 2026-08-03 00:00 | 13:37:02.36 | +16:17:44.9 | HIP 66430 | 6.14 |
| 2026-08-03 12:00 | 13:37:03.96 | +16:16:40.1 | HIP 66430 | 7.14 |
| 2026-08-04 00:00 | 13:37:05.60 | +16:15:35.2 | HIP 66430 | 8.17 |
| 2026-08-04 12:00 | 13:37:07.30 | +16:14:30.2 | HIP 66430 | 9.24 |
| 2026-08-05 00:00 | 13:37:09.04 | +16:13:25.1 | HIP 66430 | 10.33 |
| 2026-08-05 12:00 | 13:37:10.84 | +16:12:19.9 | HIP 66430 | 11.43 |
| 2026-08-06 00:00 | 13:37:12.68 | +16:11:14.6 | HIP 66430 | 12.55 |
| 2026-08-06 12:00 | 13:37:14.58 | +16:10:09.3 | HIP 66430 | 13.68 |
| 2026-08-07 00:00 | 13:37:16.52 | +16:09:03.8 | HIP 66430 | 14.82 |
| 2026-08-07 12:00 | 13:37:18.51 | +16:07:58.3 | HIP 66430 | 15.97 |
| 2026-08-08 00:00 | 13:37:20.55 | +16:06:52.7 | HIP 66436 | 17.05 |
| 2026-08-08 12:00 | 13:37:22.64 | +16:05:47.0 | HIP 66436 | 16.04 |
| 2026-08-09 00:00 | 13:37:24.77 | +16:04:41.3 | HIP 66436 | 15.06 |
| 2026-08-09 12:00 | 13:37:26.96 | +16:03:35.5 | HIP 66436 | 14.12 |
| 2026-08-10 00:00 | 13:37:29.19 | +16:02:29.6 | HIP 66436 | 13.23 |
| 2026-08-10 12:00 | 13:37:31.47 | +16:01:23.7 | HIP 66436 | 12.40 |
| 2026-08-11 00:00 | 13:37:33.80 | +16:00:17.7 | HIP 66436 | 11.64 |
| 2026-08-11 12:00 | 13:37:36.17 | +15:59:11.7 | HIP 66436 | 10.97 |
| 2026-08-12 00:00 | 13:37:38.59 | +15:58:05.6 | HIP 66436 | 10.42 |
| 2026-08-12 12:00 | 13:37:41.06 | +15:56:59.5 | HIP 66436 | 10.00 |
| 2026-08-13 00:00 | 13:37:43.57 | +15:55:53.3 | HIP 66436 | 9.73 |
| 2026-08-13 12:00 | 13:37:46.13 | +15:54:47.1 | HIP 66436 | 9.63 |
| 2026-08-14 00:00 | 13:37:48.74 | +15:53:40.9 | HIP 66436 | 9.71 |
| 2026-08-14 12:00 | 13:37:51.39 | +15:52:34.7 | HIP 66436 | 9.96 |
| 2026-08-15 00:00 | 13:37:54.09 | +15:51:28.4 | HIP 66436 | 10.37 |
| 2026-08-15 12:00 | 13:37:56.83 | +15:50:22.1 | HIP 66436 | 10.92 |
| 2026-08-16 00:00 | 13:37:59.62 | +15:49:15.7 | HIP 66436 | 11.61 |
| 2026-08-16 12:00 | 13:38:02.45 | +15:48:09.4 | HIP 66436 | 12.40 |
| 2026-08-17 00:00 | 13:38:05.32 | +15:47:03.0 | HIP 66436 | 13.29 |
| 2026-08-17 12:00 | 13:38:08.24 | +15:45:56.7 | HIP 66436 | 14.25 |
| 2026-08-18 00:00 | 13:38:11.21 | +15:44:50.3 | HIP 66436 | 15.27 |
| 2026-08-18 12:00 | 13:38:14.21 | +15:43:44.0 | HIP 66436 | 16.34 |
| 2026-08-19 00:00 | 13:38:17.26 | +15:42:37.6 | HIP 66436 | 17.46 |