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)
2026-03-26 00:00	20:32:59.27	-04:35:06.9	HIP 101387	35.20
2026-03-26 12:00	20:33:23.52	-04:31:58.1	HIP 101616	35.80
2026-03-27 00:00	20:33:47.68	-04:28:48.7	HIP 101616	31.47
2026-03-27 12:00	20:34:11.75	-04:25:38.7	HIP 101616	28.16
2026-03-28 00:00	20:34:35.72	-04:22:27.9	HIP 101616	26.23
2026-03-28 12:00	20:34:59.61	-04:19:16.5	HIP 101616	26.01
2026-03-29 00:00	20:35:23.40	-04:16:04.5	HIP 101616	27.50
2026-03-29 12:00	20:35:47.10	-04:12:51.7	HIP 101616	30.46
2026-03-30 00:00	20:36:10.71	-04:09:38.4	HIP 101827	32.26
2026-03-30 12:00	20:36:34.22	-04:06:24.3	HIP 101827	28.75
2026-03-31 00:00	20:36:57.63	-04:03:09.6	HIP 101827	26.52
2026-03-31 12:00	20:37:20.95	-03:59:54.3	HIP 101827	25.89
2026-04-01 00:00	20:37:44.17	-03:56:38.3	HIP 101827	26.97
2026-04-01 12:00	20:38:07.30	-03:53:21.7	HIP 101827	29.55
2026-04-02 00:00	20:38:30.32	-03:50:04.4	HIP 101827	33.28
2026-04-02 12:00	20:38:53.24	-03:46:46.5	HIP 101853	36.40
2026-04-03 00:00	20:39:16.06	-03:43:27.9	HIP 101853	34.98
2026-04-03 12:00	20:39:38.78	-03:40:08.7	HIP 101853	34.76
2026-04-04 00:00	20:40:01.39	-03:36:48.8	HIP 102135	29.57
2026-04-04 12:00	20:40:23.90	-03:33:28.3	HIP 102135	23.07
2026-04-05 00:00	20:40:46.31	-03:30:07.2	HIP 102135	16.62
2026-04-05 12:00	20:41:08.61	-03:26:45.4	HIP 102135	10.28
2026-04-06 00:00	20:41:30.80	-03:23:23.0	HIP 102135	4.45
2026-04-06 12:00	20:41:52.88	-03:20:00.0	HIP 102135	4.26
2026-04-07 00:00	20:42:14.85	-03:16:36.3	HIP 102135	10.00
2026-04-07 12:00	20:42:36.71	-03:13:12.1	HIP 102135	16.26
2026-04-08 00:00	20:42:58.45	-03:09:47.2	HIP 102135	22.61
2026-04-08 12:00	20:43:20.08	-03:06:21.7	HIP 102135	28.96
2026-04-09 00:00	20:43:41.60	-03:02:55.5	HIP 102272	33.41
2026-04-09 12:00	20:44:03.00	-02:59:28.8	HIP 102272	31.40
2026-04-10 00:00	20:44:24.29	-02:56:01.4	HIP 102272	30.58
2026-04-10 12:00	20:44:45.45	-02:52:33.5	HIP 102304	29.94
2026-04-11 00:00	20:45:06.50	-02:49:04.9	HIP 102547	26.63
2026-04-11 12:00	20:45:27.42	-02:45:35.8	HIP 102547	20.85
2026-04-12 00:00	20:45:48.22	-02:42:06.0	HIP 102547	15.50
2026-04-12 12:00	20:46:08.90	-02:38:35.7	HIP 102547	11.18
2026-04-13 00:00	20:46:29.45	-02:35:04.8	HIP 102547	9.38
2026-04-13 12:00	20:46:49.87	-02:31:33.3	HIP 102561	4.15
2026-04-14 00:00	20:47:10.17	-02:28:01.2	HIP 102561	2.03
2026-04-14 12:00	20:47:30.34	-02:24:28.5	HIP 102561	8.19
2026-04-15 00:00	20:47:50.37	-02:20:55.3	HIP 102561	14.33
2026-04-15 12:00	20:48:10.28	-02:17:21.5	HIP 102561	20.45
2026-04-16 00:00	20:48:30.05	-02:13:47.1	HIP 102561	26.54