Comet Archive

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C/1987 W1 (Ichimura)

メタデータ

項目 値
Designation C/1987 W1 (Ichimura)
Type C
Perihelion (tp_cal, UTC) 1988-01-10T02:29:58.758720Z
Orbit solution date (soln_date, UTC) 2021-04-15T23:29:36Z
Obs used 48
NEO -
M1 8.900
K1 10.000
PC -
オスキュレーティング軌道要素
項目 値
Epoch (epoch_cal, TDB) 1987-11-28.0000000
e 0.99999939
q (au) 0.199518
a (au) 327902.551553
i (deg) 41.620500
Ω (om, deg) 226.527901
ω (w, deg) 329.292632
M (ma, deg) 360.000000

等級

C/1987 W1 (Ichimura) · Magnitude (Full range)

散乱 + 全体線形

$$ M_a = (10.504 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目 値
H0 10.504
n 2.000
gf 0.800
gb -1.000
k 0.824
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

天体暦

Date/Time (UTC) RA (J2000) Dec (J2000) Nearest HIP Dist from HIP (arcmin)
2026-02-03 00:00 00:19:39.03 +27:48:13.7 HIP 1699 23.03
2026-02-03 12:00 00:19:40.26 +27:48:10.4 HIP 1699 22.75
2026-02-04 00:00 00:19:41.51 +27:48:07.1 HIP 1699 22.47
2026-02-04 12:00 00:19:42.76 +27:48:04.0 HIP 1699 22.18
2026-02-05 00:00 00:19:44.04 +27:48:01.0 HIP 1699 21.90
2026-02-05 12:00 00:19:45.32 +27:47:58.2 HIP 1699 21.61
2026-02-06 00:00 00:19:46.62 +27:47:55.5 HIP 1699 21.32
2026-02-06 12:00 00:19:47.93 +27:47:52.9 HIP 1699 21.03
2026-02-07 00:00 00:19:49.25 +27:47:50.5 HIP 1699 20.73
2026-02-07 12:00 00:19:50.58 +27:47:48.2 HIP 1699 20.44
2026-02-08 00:00 00:19:51.93 +27:47:46.1 HIP 1699 20.14
2026-02-08 12:00 00:19:53.28 +27:47:44.0 HIP 1699 19.84
2026-02-09 00:00 00:19:54.65 +27:47:42.2 HIP 1699 19.53
2026-02-09 12:00 00:19:56.04 +27:47:40.4 HIP 1699 19.23
2026-02-10 00:00 00:19:57.43 +27:47:38.8 HIP 1699 18.92
2026-02-10 12:00 00:19:58.83 +27:47:37.3 HIP 1699 18.61
2026-02-11 00:00 00:20:00.25 +27:47:36.0 HIP 1699 18.30
2026-02-11 12:00 00:20:01.68 +27:47:34.8 HIP 1699 17.99
2026-02-12 00:00 00:20:03.12 +27:47:33.7 HIP 1699 17.67
2026-02-12 12:00 00:20:04.57 +27:47:32.8 HIP 1699 17.35
2026-02-13 00:00 00:20:06.03 +27:47:32.0 HIP 1699 17.03
2026-02-13 12:00 00:20:07.50 +27:47:31.4 HIP 1699 16.71
2026-02-14 00:00 00:20:08.98 +27:47:30.8 HIP 1699 16.39
2026-02-14 12:00 00:20:10.48 +27:47:30.5 HIP 1699 16.07
2026-02-15 00:00 00:20:11.98 +27:47:30.2 HIP 1699 15.74
2026-02-15 12:00 00:20:13.50 +27:47:30.1 HIP 1699 15.41
2026-02-16 00:00 00:20:15.02 +27:47:30.2 HIP 1699 15.08
2026-02-16 12:00 00:20:16.56 +27:47:30.3 HIP 1699 14.76
2026-02-17 00:00 00:20:18.10 +27:47:30.6 HIP 1699 14.42
2026-02-17 12:00 00:20:19.66 +27:47:31.1 HIP 1699 14.09
2026-02-18 00:00 00:20:21.22 +27:47:31.7 HIP 1699 13.76
2026-02-18 12:00 00:20:22.80 +27:47:32.4 HIP 1699 13.43
2026-02-19 00:00 00:20:24.39 +27:47:33.2 HIP 1699 13.09
2026-02-19 12:00 00:20:25.98 +27:47:34.2 HIP 1699 12.76
2026-02-20 00:00 00:20:27.58 +27:47:35.3 HIP 1699 12.42
2026-02-20 12:00 00:20:29.20 +27:47:36.6 HIP 1699 12.09
2026-02-21 00:00 00:20:30.82 +27:47:38.0 HIP 1699 11.75
2026-02-21 12:00 00:20:32.45 +27:47:39.5 HIP 1699 11.42
2026-02-22 00:00 00:20:34.09 +27:47:41.2 HIP 1699 11.08
2026-02-22 12:00 00:20:35.74 +27:47:43.0 HIP 1699 10.75
2026-02-23 00:00 00:20:37.40 +27:47:44.9 HIP 1699 10.42
2026-02-23 12:00 00:20:39.06 +27:47:47.0 HIP 1699 10.09
2026-02-24 00:00 00:20:40.74 +27:47:49.2 HIP 1699 9.76