メタデータ

項目	値
Designation	153P/Ikeya-Zhang
Type	P
Perihelion (tp_cal, UTC)	2002-03-18T23:31:25.772160Z
Orbit solution date (soln_date, UTC)	2020-06-17T10:40:41Z
Obs used	1893
NEO	-
M1	4.000
K1	15.000
PC	-

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2002-05-08.0000000
e	0.99008066
q (au)	0.507070
a (au)	51.119322
i (deg)	28.120957
Ω (om, deg)	93.369457
ω (w, deg)	34.668179
M (ma, deg)	0.134887

等級

散乱 + 全体線形

$$ M_a = (6.663 + 3.285\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	6.663
n	3.285
gf	0.800
gb	-0.500
k	0.926
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
2001-08-25	2002-02-03	+7.8285	+1.084
2002-02-03	2002-03-18	+3.0730	+0.799
2002-03-19	2002-06-13	+0.2070	+0.282
2002-06-13	2002-10-11	+6.0428	-0.737

log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)

天体暦

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-06-01 00:00	20:05:56.25	-32:14:19.8	HIP 98842	23.21
2026-06-01 12:00	20:05:54.19	-32:14:32.3	HIP 98842	22.93
2026-06-02 00:00	20:05:52.12	-32:14:44.8	HIP 98842	22.65
2026-06-02 12:00	20:05:50.02	-32:14:57.3	HIP 98842	22.37
2026-06-03 00:00	20:05:47.90	-32:15:09.8	HIP 98842	22.10
2026-06-03 12:00	20:05:45.76	-32:15:22.3	HIP 98842	21.83
2026-06-04 00:00	20:05:43.60	-32:15:34.8	HIP 98842	21.57
2026-06-04 12:00	20:05:41.42	-32:15:47.4	HIP 98842	21.31
2026-06-05 00:00	20:05:39.22	-32:15:59.9	HIP 98842	21.06
2026-06-05 12:00	20:05:37.00	-32:16:12.4	HIP 98842	20.81
2026-06-06 00:00	20:05:34.75	-32:16:24.9	HIP 98842	20.57
2026-06-06 12:00	20:05:32.49	-32:16:37.5	HIP 98842	20.34
2026-06-07 00:00	20:05:30.21	-32:16:50.0	HIP 98842	20.11
2026-06-07 12:00	20:05:27.91	-32:17:02.5	HIP 98842	19.90
2026-06-08 00:00	20:05:25.59	-32:17:15.0	HIP 98842	19.69
2026-06-08 12:00	20:05:23.25	-32:17:27.5	HIP 98842	19.49
2026-06-09 00:00	20:05:20.89	-32:17:40.0	HIP 98842	19.30
2026-06-09 12:00	20:05:18.51	-32:17:52.5	HIP 98842	19.13
2026-06-10 00:00	20:05:16.11	-32:18:05.0	HIP 98842	18.96
2026-06-10 12:00	20:05:13.69	-32:18:17.5	HIP 98842	18.81
2026-06-11 00:00	20:05:11.26	-32:18:29.9	HIP 98842	18.66
2026-06-11 12:00	20:05:08.80	-32:18:42.4	HIP 98842	18.54
2026-06-12 00:00	20:05:06.33	-32:18:54.8	HIP 98842	18.42
2026-06-12 12:00	20:05:03.84	-32:19:07.2	HIP 98842	18.32
2026-06-13 00:00	20:05:01.34	-32:19:19.6	HIP 98842	18.24
2026-06-13 12:00	20:04:58.81	-32:19:32.0	HIP 98842	18.17
2026-06-14 00:00	20:04:56.27	-32:19:44.4	HIP 98842	18.11
2026-06-14 12:00	20:04:53.71	-32:19:56.8	HIP 98842	18.08
2026-06-15 00:00	20:04:51.13	-32:20:09.1	HIP 98842	18.06
2026-06-15 12:00	20:04:48.54	-32:20:21.4	HIP 98842	18.05
2026-06-16 00:00	20:04:45.93	-32:20:33.7	HIP 98842	18.07
2026-06-16 12:00	20:04:43.30	-32:20:46.0	HIP 98842	18.10
2026-06-17 00:00	20:04:40.66	-32:20:58.2	HIP 98842	18.15
2026-06-17 12:00	20:04:38.00	-32:21:10.5	HIP 98842	18.22
2026-06-18 00:00	20:04:35.33	-32:21:22.7	HIP 98842	18.31
2026-06-18 12:00	20:04:32.64	-32:21:34.8	HIP 98842	18.41
2026-06-19 00:00	20:04:29.93	-32:21:47.0	HIP 98842	18.54
2026-06-19 12:00	20:04:27.21	-32:21:59.1	HIP 98842	18.68
2026-06-20 00:00	20:04:24.48	-32:22:11.2	HIP 98842	18.84
2026-06-20 12:00	20:04:21.73	-32:22:23.3	HIP 98782	18.96
2026-06-21 00:00	20:04:18.97	-32:22:35.3	HIP 98782	18.90
2026-06-21 12:00	20:04:16.19	-32:22:47.3	HIP 98782	18.86
2026-06-22 00:00	20:04:13.40	-32:22:59.2	HIP 98782	18.84