メタデータ

項目	値
Designation	270P/Gehrels
Type	P
Perihelion (tp_cal, UTC)	2013-07-18T12:29:23.700480Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:28:10Z
Obs used	381
NEO	-
M1	13.700
K1	4.500
PC	-

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2008-07-20.0000000
e	0.46760427
q (au)	3.594521
a (au)	6.751596
i (deg)	2.859570
Ω (om, deg)	225.681440
ω (w, deg)	211.476072
M (ma, deg)	257.495456

等級

散乱 + 全体線形

$$ M_a = (6.875 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	6.875
n	6.000
gf	1.000
gb	-0.503
k	1.000
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

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	20:15:49.56	-16:46:35.3	HIP 99823	9.70
2026-05-12 12:00	20:15:49.31	-16:46:23.8	HIP 99823	9.74
2026-05-13 00:00	20:15:48.92	-16:46:12.8	HIP 99823	9.75
2026-05-13 12:00	20:15:48.41	-16:46:02.2	HIP 99823	9.73
2026-05-14 00:00	20:15:47.76	-16:45:52.0	HIP 99823	9.69
2026-05-14 12:00	20:15:47.00	-16:45:42.2	HIP 99823	9.62
2026-05-15 00:00	20:15:46.10	-16:45:32.8	HIP 99823	9.53
2026-05-15 12:00	20:15:45.07	-16:45:23.9	HIP 99823	9.42
2026-05-16 00:00	20:15:43.92	-16:45:15.4	HIP 99823	9.29
2026-05-16 12:00	20:15:42.64	-16:45:07.4	HIP 99823	9.14
2026-05-17 00:00	20:15:41.23	-16:44:59.8	HIP 99823	8.97
2026-05-17 12:00	20:15:39.69	-16:44:52.6	HIP 99823	8.79
2026-05-18 00:00	20:15:38.02	-16:44:45.8	HIP 99823	8.59
2026-05-18 12:00	20:15:36.23	-16:44:39.5	HIP 99823	8.38
2026-05-19 00:00	20:15:34.31	-16:44:33.6	HIP 99823	8.17
2026-05-19 12:00	20:15:32.26	-16:44:28.2	HIP 99823	7.96
2026-05-20 00:00	20:15:30.09	-16:44:23.2	HIP 99823	7.75
2026-05-20 12:00	20:15:27.78	-16:44:18.6	HIP 99823	7.55
2026-05-21 00:00	20:15:25.35	-16:44:14.5	HIP 99823	7.37
2026-05-21 12:00	20:15:22.80	-16:44:10.7	HIP 99800	7.07
2026-05-22 00:00	20:15:20.12	-16:44:07.5	HIP 99800	6.44
2026-05-22 12:00	20:15:17.31	-16:44:04.6	HIP 99800	5.79
2026-05-23 00:00	20:15:14.38	-16:44:02.2	HIP 99800	5.10
2026-05-23 12:00	20:15:11.32	-16:44:00.2	HIP 99800	4.40
2026-05-24 00:00	20:15:08.14	-16:43:58.7	HIP 99800	3.67
2026-05-24 12:00	20:15:04.83	-16:43:57.6	HIP 99800	2.93
2026-05-25 00:00	20:15:01.40	-16:43:56.9	HIP 99800	2.19
2026-05-25 12:00	20:14:57.84	-16:43:56.6	HIP 99800	1.52
2026-05-26 00:00	20:14:54.17	-16:43:56.8	HIP 99800	1.11
2026-05-26 12:00	20:14:50.36	-16:43:57.4	HIP 99800	1.32
2026-05-27 00:00	20:14:46.44	-16:43:58.5	HIP 99800	2.00
2026-05-27 12:00	20:14:42.39	-16:44:00.0	HIP 99800	2.85
2026-05-28 00:00	20:14:38.22	-16:44:01.8	HIP 99800	3.79
2026-05-28 12:00	20:14:33.92	-16:44:04.1	HIP 99800	4.78
2026-05-29 00:00	20:14:29.51	-16:44:06.9	HIP 99800	5.81
2026-05-29 12:00	20:14:24.97	-16:44:10.1	HIP 99800	6.88
2026-05-30 00:00	20:14:20.32	-16:44:13.6	HIP 99708	6.54
2026-05-30 12:00	20:14:15.54	-16:44:17.7	HIP 99708	5.74
2026-05-31 00:00	20:14:10.64	-16:44:22.1	HIP 99708	5.07
2026-05-31 12:00	20:14:05.62	-16:44:27.0	HIP 99708	4.59
2026-06-01 00:00	20:14:00.48	-16:44:32.3	HIP 99708	4.41
2026-06-01 12:00	20:13:55.22	-16:44:38.0	HIP 99708	4.58
2026-06-02 00:00	20:13:49.85	-16:44:44.1	HIP 99708	5.09