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)
2026-06-01 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
2026-06-02 12:00	21:05:52.81	+03:55:34.6	HIP 104202	13.86
2026-06-03 00:00	21:05:52.09	+03:59:35.2	HIP 104202	16.48
2026-06-03 12:00	21:05:51.05	+04:03:35.5	HIP 104224	16.09
2026-06-04 00:00	21:05:49.69	+04:07:35.7	HIP 104224	16.52
2026-06-04 12:00	21:05:48.01	+04:11:35.6	HIP 104137	14.26
2026-06-05 00:00	21:05:46.01	+04:15:35.3	HIP 104137	10.44
2026-06-05 12:00	21:05:43.69	+04:19:34.6	HIP 104137	6.89
2026-06-06 00:00	21:05:41.03	+04:23:33.7	HIP 104137	4.37
2026-06-06 12:00	21:05:38.05	+04:27:32.5	HIP 104137	4.91
2026-06-07 00:00	21:05:34.73	+04:31:31.0	HIP 104137	7.92
2026-06-07 12:00	21:05:31.07	+04:35:29.1	HIP 104137	11.63
2026-06-08 00:00	21:05:27.07	+04:39:26.8	HIP 104137	15.55
2026-06-08 12:00	21:05:22.74	+04:43:24.2	HIP 104137	19.58
2026-06-09 00:00	21:05:18.05	+04:47:21.1	HIP 104137	23.65
2026-06-09 12:00	21:05:13.02	+04:51:17.6	HIP 104137	27.77
2026-06-10 00:00	21:05:07.64	+04:55:13.7	HIP 104137	31.92
2026-06-10 12:00	21:05:01.90	+04:59:09.2	HIP 104031	31.75
2026-06-11 00:00	21:04:55.81	+05:03:04.3	HIP 104031	27.61
2026-06-11 12:00	21:04:49.36	+05:06:58.8	HIP 104031	23.48
2026-06-12 00:00	21:04:42.55	+05:10:52.8	HIP 104031	19.39
2026-06-12 12:00	21:04:35.38	+05:14:46.2	HIP 104031	15.40
2026-06-13 00:00	21:04:27.84	+05:18:39.0	HIP 104031	11.65
2026-06-13 12:00	21:04:19.92	+05:22:31.1	HIP 104031	8.48
2026-06-14 00:00	21:04:11.64	+05:26:22.6	HIP 104031	6.87
2026-06-14 12:00	21:04:02.99	+05:30:13.4	HIP 104031	7.88
2026-06-15 00:00	21:03:53.95	+05:34:03.5	HIP 104031	10.85
2026-06-15 12:00	21:03:44.54	+05:37:52.9	HIP 104031	14.66
2026-06-16 00:00	21:03:34.75	+05:41:41.5	HIP 103835	18.82
2026-06-16 12:00	21:03:24.57	+05:45:29.3	HIP 103835	18.71
2026-06-17 00:00	21:03:14.01	+05:49:16.3	HIP 103835	19.62
2026-06-17 12:00	21:03:03.07	+05:53:02.5	HIP 103835	21.45
2026-06-18 00:00	21:02:51.73	+05:56:47.8	HIP 103835	24.01
2026-06-18 12:00	21:02:40.00	+06:00:32.2	HIP 103835	27.12
2026-06-19 00:00	21:02:27.88	+06:04:15.7	HIP 104010	30.53
2026-06-19 12:00	21:02:15.36	+06:07:58.2	HIP 104010	32.19
2026-06-20 00:00	21:02:02.45	+06:11:39.8	HIP 104010	34.56
2026-06-20 12:00	21:01:49.14	+06:15:20.3	HIP 104010	37.52
2026-06-21 00:00	21:01:35.43	+06:18:59.9	HIP 104010	40.97
2026-06-21 12:00	21:01:21.31	+06:22:38.3	HIP 104010	44.81
2026-06-22 00:00	21:01:06.79	+06:26:15.7	HIP 103813	47.42