メタデータ

項目	値
Designation	P/2020 G1 (Pimentel)
Type	P
Perihelion (tp_cal, UTC)	2020-03-17T09:47:11.889600Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:34:05Z
Obs used	490
NEO	Yes
M1	17.400
K1	4.500
PC	0.030

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2020-05-04.0000000
e	0.85961155
q (au)	0.505764
a (au)	3.602603
i (deg)	18.472732
Ω (om, deg)	240.105496
ω (w, deg)	207.637592
M (ma, deg)	6.859863

等級

散乱 + 全体線形

$$ M_a = (17.331 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	17.331
n	2.000
gf	0.800
gb	-0.696
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
2020-04-13	2020-04-29	+4.8811	+0.451
2020-04-29	2020-05-31	-5.2578	+0.285
2020-05-31	2020-07-19	+18.1081	-3.892

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	21:01:59.75	+01:03:03.0	HIP 103742	9.46
2026-05-12 12:00	21:02:10.39	+01:07:00.6	HIP 103742	12.38
2026-05-13 00:00	21:02:20.80	+01:10:58.6	HIP 103742	16.15
2026-05-13 12:00	21:02:30.99	+01:14:56.8	HIP 103892	18.78
2026-05-14 00:00	21:02:40.96	+01:18:55.3	HIP 103892	14.14
2026-05-14 12:00	21:02:50.71	+01:22:54.0	HIP 103892	9.55
2026-05-15 00:00	21:03:00.22	+01:26:53.0	HIP 103892	5.10
2026-05-15 12:00	21:03:09.51	+01:30:52.2	HIP 103892	1.92
2026-05-16 00:00	21:03:18.56	+01:34:51.6	HIP 103892	4.85
2026-05-16 12:00	21:03:27.37	+01:38:51.3	HIP 103893	6.44
2026-05-17 00:00	21:03:35.96	+01:42:51.1	HIP 103893	8.04
2026-05-17 12:00	21:03:44.30	+01:46:51.2	HIP 103893	11.30
2026-05-18 00:00	21:03:52.40	+01:50:51.4	HIP 103893	15.17
2026-05-18 12:00	21:04:00.25	+01:54:51.8	HIP 103893	19.27
2026-05-19 00:00	21:04:07.87	+01:58:52.4	HIP 104048	19.69
2026-05-19 12:00	21:04:15.23	+02:02:53.1	HIP 104048	15.29
2026-05-20 00:00	21:04:22.35	+02:06:54.0	HIP 104048	10.92
2026-05-20 12:00	21:04:29.22	+02:10:55.0	HIP 104048	6.64
2026-05-21 00:00	21:04:35.83	+02:14:56.1	HIP 104048	2.69
2026-05-21 12:00	21:04:42.19	+02:18:57.3	HIP 104048	2.87
2026-05-22 00:00	21:04:48.29	+02:22:58.7	HIP 104048	6.82
2026-05-22 12:00	21:04:54.13	+02:27:00.1	HIP 104048	11.03
2026-05-23 00:00	21:04:59.71	+02:31:01.7	HIP 104005	14.75
2026-05-23 12:00	21:05:05.03	+02:35:03.3	HIP 104005	13.41
2026-05-24 00:00	21:05:10.09	+02:39:04.9	HIP 104005	13.28
2026-05-24 12:00	21:05:14.87	+02:43:06.6	HIP 104005	14.37
2026-05-25 00:00	21:05:19.39	+02:47:08.4	HIP 104041	13.31
2026-05-25 12:00	21:05:23.64	+02:51:10.2	HIP 104041	11.78
2026-05-26 00:00	21:05:27.61	+02:55:12.1	HIP 104041	11.56
2026-05-26 12:00	21:05:31.31	+02:59:13.9	HIP 104041	12.69
2026-05-27 00:00	21:05:34.73	+03:03:15.8	HIP 104041	14.86
2026-05-27 12:00	21:05:37.87	+03:07:17.6	HIP 104041	17.69
2026-05-28 00:00	21:05:40.72	+03:11:19.4	HIP 104041	20.89
2026-05-28 12:00	21:05:43.30	+03:15:21.2	HIP 104047	22.11
2026-05-29 00:00	21:05:45.58	+03:19:23.0	HIP 104047	19.69
2026-05-29 12:00	21:05:47.57	+03:23:24.7	HIP 104047	17.81
2026-05-30 00:00	21:05:49.28	+03:27:26.3	HIP 104047	16.66
2026-05-30 12:00	21:05:50.69	+03:31:27.8	HIP 104047	16.37
2026-05-31 00:00	21:05:51.80	+03:35:29.3	HIP 104047	16.99
2026-05-31 12:00	21:05:52.61	+03:39:30.6	HIP 104202	14.62
2026-06-01 00:00	21:05:53.12	+03:43:31.8	HIP 104202	12.54
2026-06-01 12:00	21:05:53.32	+03:47:32.9	HIP 104202	11.61
2026-06-02 00:00	21:05:53.22	+03:51:33.8	HIP 104202	12.10