C/2017 S6 (Catalina)

メタデータ

項目 値
Designation C/2017 S6 (Catalina)
Type C
Perihelion (tp_cal, UTC) 2018-02-26T22:22:53.693760Z
Orbit solution date (soln_date, UTC) 2021-04-15T23:33:35Z
Obs used 247
NEO -
M1 15.300
K1 4.750
PC -
オスキュレーティング軌道要素
項目 値
Epoch (epoch_cal, TDB) 2017-11-15.0000000
e 1.00140730
q (au) 1.542930
a (au) -1096.375698
i (deg) 152.826812
Ω (om, deg) 130.873122
ω (w, deg) 134.685410
M (ma, deg) -0.002822

等級

C/2017 S6 (Catalina) · Magnitude (Full range)

散乱 + 全体線形

$$ M_a = (17.010 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目 値
H0 17.010
n 2.000
gf 1.000
gb -0.676
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
2017-02-16 2017-10-28 +4.8973 -2.493
2017-10-28 2018-02-05 +7.2164 -2.343

log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)

天体暦

Date/Time (UTC) RA (J2000) Dec (J2000) Nearest HIP Dist from HIP (arcmin)
2026-09-20 00:00 12:45:40.73 -32:30:10.0 HIP 62485 34.84
2026-09-20 12:00 12:45:45.78 -32:30:23.9 HIP 62485 33.90
2026-09-21 00:00 12:45:50.83 -32:30:38.2 HIP 62485 32.97
2026-09-21 12:00 12:45:55.89 -32:30:52.9 HIP 62485 32.05
2026-09-22 00:00 12:46:00.96 -32:31:07.8 HIP 62485 31.15
2026-09-22 12:00 12:46:06.04 -32:31:23.1 HIP 62485 30.25
2026-09-23 00:00 12:46:11.13 -32:31:38.7 HIP 62485 29.37
2026-09-23 12:00 12:46:16.23 -32:31:54.7 HIP 62485 28.51
2026-09-24 00:00 12:46:21.34 -32:32:10.9 HIP 62485 27.67
2026-09-24 12:00 12:46:26.46 -32:32:27.5 HIP 62485 26.85
2026-09-25 00:00 12:46:31.58 -32:32:44.4 HIP 62485 26.05
2026-09-25 12:00 12:46:36.71 -32:33:01.7 HIP 62485 25.28
2026-09-26 00:00 12:46:41.84 -32:33:19.2 HIP 62485 24.53
2026-09-26 12:00 12:46:46.99 -32:33:37.1 HIP 62485 23.82
2026-09-27 00:00 12:46:52.14 -32:33:55.3 HIP 62485 23.14
2026-09-27 12:00 12:46:57.29 -32:34:13.8 HIP 62485 22.50
2026-09-28 00:00 12:47:02.45 -32:34:32.6 HIP 62485 21.90
2026-09-28 12:00 12:47:07.62 -32:34:51.7 HIP 62485 21.35
2026-09-29 00:00 12:47:12.79 -32:35:11.2 HIP 62485 20.85
2026-09-29 12:00 12:47:17.97 -32:35:30.9 HIP 62485 20.41
2026-09-30 00:00 12:47:23.15 -32:35:50.9 HIP 62485 20.02
2026-09-30 12:00 12:47:28.33 -32:36:11.3 HIP 62485 19.70
2026-10-01 00:00 12:47:33.52 -32:36:32.0 HIP 62485 19.45
2026-10-01 12:00 12:47:38.71 -32:36:52.9 HIP 62485 19.26
2026-10-02 00:00 12:47:43.90 -32:37:14.2 HIP 62485 19.14
2026-10-02 12:00 12:47:49.10 -32:37:35.8 HIP 62485 19.10
2026-10-03 00:00 12:47:54.30 -32:37:57.6 HIP 62485 19.13
2026-10-03 12:00 12:47:59.50 -32:38:19.8 HIP 62485 19.24
2026-10-04 00:00 12:48:04.70 -32:38:42.3 HIP 62485 19.42
2026-10-04 12:00 12:48:09.91 -32:39:05.0 HIP 62485 19.67
2026-10-05 00:00 12:48:15.11 -32:39:28.1 HIP 62485 19.99
2026-10-05 12:00 12:48:20.32 -32:39:51.4 HIP 62485 20.38
2026-10-06 00:00 12:48:25.53 -32:40:15.1 HIP 62485 20.83
2026-10-06 12:00 12:48:30.73 -32:40:39.0 HIP 62485 21.34
2026-10-07 00:00 12:48:35.94 -32:41:03.2 HIP 62485 21.91
2026-10-07 12:00 12:48:41.14 -32:41:27.7 HIP 62485 22.52
2026-10-08 00:00 12:48:46.34 -32:41:52.5 HIP 62485 23.18
2026-10-08 12:00 12:48:51.55 -32:42:17.5 HIP 62485 23.89
2026-10-09 00:00 12:48:56.75 -32:42:42.9 HIP 62485 24.64
2026-10-09 12:00 12:49:01.94 -32:43:08.5 HIP 62485 25.42
2026-10-10 00:00 12:49:07.14 -32:43:34.4 HIP 62485 26.24
2026-10-10 12:00 12:49:12.33 -32:44:00.5 HIP 62485 27.08
2026-10-11 00:00 12:49:17.51 -32:44:27.0 HIP 62481 27.72