C/2021 T4 (Lemmon)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2021 T4 (Lemmon) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2023-07-31T12:38:55.115520Z |
| Orbit solution date (soln_date, UTC) | 2025-04-14T09:29:19Z |
| Obs used | 1259 |
| NEO | - |
| M1 | 12.400 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2021-10-07T08:22:46.128000Z |
| Discovery magnitude (MPC) | 20.27 G |
| Discovery observatory (MPC) | G96 · Mt. Lemmon Survey |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2023-04-14.0000000 |
| e | 0.99991819 |
| q (au) | 1.483298 |
| a (au) | 18131.786728 |
| i (deg) | 160.777409 |
| Ω (om, deg) | 257.882312 |
| ω (w, deg) | 329.813930 |
| M (ma, deg) | 359.999956 |
等級
散乱 + 全体線形
$$ M_a = (12.728 + 3.054\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 12.728 |
| n | 3.054 |
| gf | 1.000 |
| gb | -0.748 |
| k | 0.800 |
| 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 |
|---|---|---|---|
| 2021-08-07 | 2023-07-28 | +2.7531 | -2.268 |
| 2023-07-31 | 2024-04-13 | +9.0393 | -3.499 |
| 2024-04-13 | 2025-03-24 | -0.2550 | +1.251 |
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 | 10:25:21.12 | +30:14:21.8 | HIP 50997 | 8.98 |
| 2026-05-12 12:00 | 10:25:16.14 | +30:13:41.2 | HIP 50997 | 9.16 |
| 2026-05-13 00:00 | 10:25:11.29 | +30:13:00.0 | HIP 50997 | 9.53 |
| 2026-05-13 12:00 | 10:25:06.55 | +30:12:18.2 | HIP 50997 | 10.05 |
| 2026-05-14 00:00 | 10:25:01.93 | +30:11:35.9 | HIP 50997 | 10.69 |
| 2026-05-14 12:00 | 10:24:57.44 | +30:10:53.1 | HIP 50997 | 11.44 |
| 2026-05-15 00:00 | 10:24:53.06 | +30:10:09.7 | HIP 50926 | 11.13 |
| 2026-05-15 12:00 | 10:24:48.81 | +30:09:25.9 | HIP 50926 | 10.40 |
| 2026-05-16 00:00 | 10:24:44.67 | +30:08:41.5 | HIP 50926 | 9.78 |
| 2026-05-16 12:00 | 10:24:40.65 | +30:07:56.6 | HIP 50926 | 9.30 |
| 2026-05-17 00:00 | 10:24:36.76 | +30:07:11.2 | HIP 50926 | 8.96 |
| 2026-05-17 12:00 | 10:24:32.98 | +30:06:25.4 | HIP 50926 | 8.78 |
| 2026-05-18 00:00 | 10:24:29.32 | +30:05:39.0 | HIP 50926 | 8.77 |
| 2026-05-18 12:00 | 10:24:25.78 | +30:04:52.2 | HIP 50926 | 8.91 |
| 2026-05-19 00:00 | 10:24:22.35 | +30:04:04.8 | HIP 50926 | 9.21 |
| 2026-05-19 12:00 | 10:24:19.04 | +30:03:17.1 | HIP 50926 | 9.63 |
| 2026-05-20 00:00 | 10:24:15.85 | +30:02:28.8 | HIP 50926 | 10.16 |
| 2026-05-20 12:00 | 10:24:12.78 | +30:01:40.1 | HIP 50926 | 10.78 |
| 2026-05-21 00:00 | 10:24:09.82 | +30:00:51.0 | HIP 50926 | 11.48 |
| 2026-05-21 12:00 | 10:24:06.98 | +30:00:01.4 | HIP 50926 | 12.24 |
| 2026-05-22 00:00 | 10:24:04.25 | +29:59:11.4 | HIP 50926 | 13.04 |
| 2026-05-22 12:00 | 10:24:01.63 | +29:58:21.0 | HIP 50926 | 13.87 |
| 2026-05-23 00:00 | 10:23:59.14 | +29:57:30.1 | HIP 50926 | 14.74 |
| 2026-05-23 12:00 | 10:23:56.75 | +29:56:38.9 | HIP 50926 | 15.62 |
| 2026-05-24 00:00 | 10:23:54.48 | +29:55:47.2 | HIP 50926 | 16.53 |
| 2026-05-24 12:00 | 10:23:52.32 | +29:54:55.1 | HIP 50926 | 17.44 |
| 2026-05-25 00:00 | 10:23:50.27 | +29:54:02.7 | HIP 50904 | 17.19 |
| 2026-05-25 12:00 | 10:23:48.33 | +29:53:09.8 | HIP 50904 | 16.27 |
| 2026-05-26 00:00 | 10:23:46.51 | +29:52:16.6 | HIP 50904 | 15.36 |
| 2026-05-26 12:00 | 10:23:44.79 | +29:51:22.9 | HIP 50904 | 14.44 |
| 2026-05-27 00:00 | 10:23:43.19 | +29:50:29.0 | HIP 50904 | 13.53 |
| 2026-05-27 12:00 | 10:23:41.69 | +29:49:34.6 | HIP 50904 | 12.62 |
| 2026-05-28 00:00 | 10:23:40.30 | +29:48:39.9 | HIP 50904 | 11.72 |
| 2026-05-28 12:00 | 10:23:39.03 | +29:47:44.9 | HIP 50904 | 10.81 |
| 2026-05-29 00:00 | 10:23:37.86 | +29:46:49.4 | HIP 50904 | 9.91 |
| 2026-05-29 12:00 | 10:23:36.79 | +29:45:53.7 | HIP 50904 | 9.01 |
| 2026-05-30 00:00 | 10:23:35.84 | +29:44:57.6 | HIP 50904 | 8.11 |
| 2026-05-30 12:00 | 10:23:34.99 | +29:44:01.2 | HIP 50904 | 7.22 |
| 2026-05-31 00:00 | 10:23:34.25 | +29:43:04.5 | HIP 50904 | 6.34 |
| 2026-05-31 12:00 | 10:23:33.61 | +29:42:07.4 | HIP 50904 | 5.47 |
| 2026-06-01 00:00 | 10:23:33.08 | +29:41:10.0 | HIP 50904 | 4.62 |
| 2026-06-01 12:00 | 10:23:32.65 | +29:40:12.3 | HIP 50904 | 3.81 |
| 2026-06-02 00:00 | 10:23:32.32 | +29:39:14.3 | HIP 50904 | 3.07 |