Comet Archive

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C/2018 F1 (Grauer)

メタデータ

項目
Designation C/2018 F1 (Grauer)
Type C
Perihelion (tp_cal, UTC) 2018-12-14T01:55:08.552640Z
Orbit solution date (soln_date, UTC) 2021-09-04T23:42:57Z
Obs used 221
NEO -
M1 12.700
K1 6.250
PC -
Discovery observation (MPC, UTC) 2018-03-17T08:17:23.424000Z
Discovery magnitude (MPC) 19.10 T
Discovery observatory (MPC) G96 · Mt. Lemmon Survey
オスキュレーティング軌道要素
項目
Epoch (epoch_cal, TDB) 2019-03-06.0000000
e 0.99071069
q (au) 2.993048
a (au) 322.203595
i (deg) 46.070619
Ω (om, deg) 177.285875
ω (w, deg) 71.628120
M (ma, deg) 0.013960

等級

C/2018 F1 (Grauer) · Magnitude (Full range)

散乱 + 全体線形

$$ M_a = (10.042 + 4.054\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目
H0 10.042
n 4.054
gf 0.800
gb -0.500
k 1.000
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

残差 (区間線形)

$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$

開始日 (UTC) 終了日 (UTC) a b
2017-12-22 2018-07-16 +4.3609 -2.361
2019-03-22 2019-08-08 -24.0881 +12.948

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)
2026-02-03 00:00 01:10:34.70 -10:47:55.6 HIP 5625 26.24
2026-02-03 12:00 01:10:38.11 -10:47:18.0 HIP 5625 25.66
2026-02-04 00:00 01:10:41.56 -10:46:40.1 HIP 5625 25.11
2026-02-04 12:00 01:10:45.06 -10:46:02.2 HIP 5625 24.58
2026-02-05 00:00 01:10:48.60 -10:45:24.1 HIP 5625 24.08
2026-02-05 12:00 01:10:52.18 -10:44:45.9 HIP 5625 23.61
2026-02-06 00:00 01:10:55.81 -10:44:07.7 HIP 5625 23.17
2026-02-06 12:00 01:10:59.48 -10:43:29.3 HIP 5625 22.77
2026-02-07 00:00 01:11:03.19 -10:42:50.7 HIP 5625 22.41
2026-02-07 12:00 01:11:06.94 -10:42:12.1 HIP 5625 22.09
2026-02-08 00:00 01:11:10.74 -10:41:33.4 HIP 5625 21.82
2026-02-08 12:00 01:11:14.58 -10:40:54.6 HIP 5625 21.60
2026-02-09 00:00 01:11:18.45 -10:40:15.7 HIP 5625 21.43
2026-02-09 12:00 01:11:22.37 -10:39:36.7 HIP 5625 21.32
2026-02-10 00:00 01:11:26.34 -10:38:57.6 HIP 5625 21.27
2026-02-10 12:00 01:11:30.34 -10:38:18.4 HIP 5625 21.27
2026-02-11 00:00 01:11:34.38 -10:37:39.1 HIP 5625 21.34
2026-02-11 12:00 01:11:38.46 -10:36:59.8 HIP 5625 21.47
2026-02-12 00:00 01:11:42.59 -10:36:20.3 HIP 5625 21.67
2026-02-12 12:00 01:11:46.75 -10:35:40.8 HIP 5625 21.93
2026-02-13 00:00 01:11:50.95 -10:35:01.3 HIP 5625 22.25
2026-02-13 12:00 01:11:55.19 -10:34:21.6 HIP 5625 22.63
2026-02-14 00:00 01:11:59.47 -10:33:41.9 HIP 5625 23.07
2026-02-14 12:00 01:12:03.79 -10:33:02.1 HIP 5625 23.56
2026-02-15 00:00 01:12:08.15 -10:32:22.3 HIP 5625 24.11
2026-02-15 12:00 01:12:12.54 -10:31:42.4 HIP 5625 24.72
2026-02-16 00:00 01:12:16.97 -10:31:02.5 HIP 5625 25.37
2026-02-16 12:00 01:12:21.44 -10:30:22.5 HIP 5625 26.07
2026-02-17 00:00 01:12:25.95 -10:29:42.5 HIP 5625 26.82
2026-02-17 12:00 01:12:30.49 -10:29:02.4 HIP 5625 27.61
2026-02-18 00:00 01:12:35.07 -10:28:22.3 HIP 5625 28.44
2026-02-18 12:00 01:12:39.69 -10:27:42.2 HIP 5625 29.30
2026-02-19 00:00 01:12:44.34 -10:27:02.0 HIP 5625 30.20
2026-02-19 12:00 01:12:49.02 -10:26:21.8 HIP 5625 31.14
2026-02-20 00:00 01:12:53.74 -10:25:41.6 HIP 5625 32.10
2026-02-20 12:00 01:12:58.50 -10:25:01.3 HIP 5625 33.09
2026-02-21 00:00 01:13:03.29 -10:24:21.0 HIP 5625 34.12
2026-02-21 12:00 01:13:08.11 -10:23:40.7 HIP 5814 33.91
2026-02-22 00:00 01:13:12.97 -10:23:00.4 HIP 5814 32.62
2026-02-22 12:00 01:13:17.86 -10:22:20.1 HIP 5814 31.33
2026-02-23 00:00 01:13:22.79 -10:21:39.8 HIP 5814 30.05
2026-02-23 12:00 01:13:27.74 -10:20:59.5 HIP 5814 28.77
2026-02-24 00:00 01:13:32.73 -10:20:19.2 HIP 5814 27.49