メタデータ

項目	値
Designation	65P/Gunn
Type	P
Perihelion (tp_cal, UTC)	2017-10-17T19:28:05.684160Z
Orbit solution date (soln_date, UTC)	2025-12-03T12:36:51Z
Obs used	3121
NEO	-
M1	11.600
K1	6.500
PC	-

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2020-08-06.0000000
e	0.24983241
q (au)	2.913890
a (au)	3.884319
i (deg)	9.182830
Ω (om, deg)	62.020609
ω (w, deg)	213.806901
M (ma, deg)	131.730867

等級

散乱 + 全体線形

$$ M_a = (11.097 + 2.682\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	11.097
n	2.682
gf	0.800
gb	-0.500
k	0.975
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
2021-12-05	2024-04-01	-8.4631	+4.247
2024-04-01	2026-05-16	+5.5499	-3.105

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	00:00:02.32	-08:36:00.1	HIP 118253	15.05
2026-05-12 12:00	00:00:35.36	-08:33:04.3	HIP 118253	21.95
2026-05-13 00:00	00:01:08.29	-08:30:09.4	HIP 210	22.43
2026-05-13 12:00	00:01:41.10	-08:27:15.5	HIP 210	14.44
2026-05-14 00:00	00:02:13.80	-08:24:22.5	HIP 210	7.91
2026-05-14 12:00	00:02:46.39	-08:21:30.5	HIP 210	7.99
2026-05-15 00:00	00:03:18.85	-08:18:39.4	HIP 210	14.50
2026-05-15 12:00	00:03:51.20	-08:15:49.3	HIP 373	12.93
2026-05-16 00:00	00:04:23.44	-08:13:00.2	HIP 373	4.48
2026-05-16 12:00	00:04:55.55	-08:10:12.1	HIP 373	3.99
2026-05-17 00:00	00:05:27.54	-08:07:25.0	HIP 373	12.37
2026-05-17 12:00	00:05:59.42	-08:04:38.9	HIP 373	20.72
2026-05-18 00:00	00:06:31.17	-08:01:53.8	HIP 629	18.32
2026-05-18 12:00	00:07:02.80	-07:59:09.7	HIP 629	10.04
2026-05-19 00:00	00:07:34.30	-07:56:26.7	HIP 629	1.87
2026-05-19 12:00	00:08:05.68	-07:53:44.6	HIP 629	6.50
2026-05-20 00:00	00:08:36.94	-07:51:03.7	HIP 711	4.09
2026-05-20 12:00	00:09:08.07	-07:48:23.7	HIP 711	7.18
2026-05-21 00:00	00:09:39.08	-07:45:44.8	HIP 711	14.78
2026-05-21 12:00	00:10:09.96	-07:43:07.0	HIP 711	22.71
2026-05-22 00:00	00:10:40.71	-07:40:30.2	HIP 904	19.26
2026-05-22 12:00	00:11:11.33	-07:37:54.5	HIP 977	14.20
2026-05-23 00:00	00:11:41.82	-07:35:19.8	HIP 977	9.07
2026-05-23 12:00	00:12:12.19	-07:32:46.3	HIP 977	9.47
2026-05-24 00:00	00:12:42.42	-07:30:13.8	HIP 1053	12.49
2026-05-24 12:00	00:13:12.53	-07:27:42.4	HIP 1053	13.29
2026-05-25 00:00	00:13:42.50	-07:25:12.1	HIP 1134	14.94
2026-05-25 12:00	00:14:12.34	-07:22:42.8	HIP 1134	10.79
2026-05-26 00:00	00:14:42.05	-07:20:14.7	HIP 1134	11.46
2026-05-26 12:00	00:15:11.62	-07:17:47.7	HIP 1252	7.58
2026-05-27 00:00	00:15:41.06	-07:15:21.8	HIP 1252	3.03
2026-05-27 12:00	00:16:10.37	-07:12:57.0	HIP 1252	8.87
2026-05-28 00:00	00:16:39.53	-07:10:33.3	HIP 1350	3.66
2026-05-28 12:00	00:17:08.57	-07:08:10.8	HIP 1350	4.96
2026-05-29 00:00	00:17:37.46	-07:05:49.4	HIP 1350	12.24
2026-05-29 12:00	00:18:06.22	-07:03:29.1	HIP 1350	19.68
2026-05-30 00:00	00:18:34.84	-07:01:10.0	HIP 1573	19.59
2026-05-30 12:00	00:19:03.32	-06:58:52.0	HIP 1573	16.72
2026-05-31 00:00	00:19:31.66	-06:56:35.2	HIP 1573	16.88
2026-05-31 12:00	00:19:59.86	-06:54:19.6	HIP 1573	19.96
2026-06-01 00:00	00:20:27.91	-06:52:05.1	HIP 1573	24.86
2026-06-01 12:00	00:20:55.82	-06:49:51.8	HIP 1778	27.03
2026-06-02 00:00	00:21:23.59	-06:47:39.7	HIP 1778	19.86