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)
2026-03-26 00:00	20:06:40.63	-31:53:17.9	HIP 99150	15.89
2026-03-26 12:00	20:06:42.08	-31:53:22.2	HIP 99150	15.66
2026-03-27 00:00	20:06:43.50	-31:53:26.6	HIP 99150	15.45
2026-03-27 12:00	20:06:44.89	-31:53:31.1	HIP 99150	15.24
2026-03-28 00:00	20:06:46.26	-31:53:35.7	HIP 99150	15.04
2026-03-28 12:00	20:06:47.60	-31:53:40.4	HIP 99150	14.85
2026-03-29 00:00	20:06:48.92	-31:53:45.2	HIP 99150	14.67
2026-03-29 12:00	20:06:50.21	-31:53:50.1	HIP 99150	14.50
2026-03-30 00:00	20:06:51.48	-31:53:55.1	HIP 99150	14.33
2026-03-30 12:00	20:06:52.72	-31:54:00.2	HIP 99150	14.18
2026-03-31 00:00	20:06:53.94	-31:54:05.3	HIP 99150	14.03
2026-03-31 12:00	20:06:55.13	-31:54:10.6	HIP 99150	13.90
2026-04-01 00:00	20:06:56.29	-31:54:16.0	HIP 99150	13.77
2026-04-01 12:00	20:06:57.43	-31:54:21.4	HIP 99150	13.65
2026-04-02 00:00	20:06:58.54	-31:54:27.0	HIP 99150	13.54
2026-04-02 12:00	20:06:59.63	-31:54:32.7	HIP 99150	13.44
2026-04-03 00:00	20:07:00.69	-31:54:38.4	HIP 99150	13.35
2026-04-03 12:00	20:07:01.72	-31:54:44.2	HIP 99150	13.26
2026-04-04 00:00	20:07:02.73	-31:54:50.2	HIP 99150	13.19
2026-04-04 12:00	20:07:03.71	-31:54:56.2	HIP 99150	13.13
2026-04-05 00:00	20:07:04.66	-31:55:02.3	HIP 99150	13.07
2026-04-05 12:00	20:07:05.59	-31:55:08.5	HIP 99150	13.02
2026-04-06 00:00	20:07:06.49	-31:55:14.8	HIP 99150	12.98
2026-04-06 12:00	20:07:07.37	-31:55:21.2	HIP 99150	12.95
2026-04-07 00:00	20:07:08.22	-31:55:27.7	HIP 99150	12.92
2026-04-07 12:00	20:07:09.04	-31:55:34.3	HIP 99150	12.91
2026-04-08 00:00	20:07:09.83	-31:55:40.9	HIP 99150	12.90
2026-04-08 12:00	20:07:10.60	-31:55:47.7	HIP 99150	12.90
2026-04-09 00:00	20:07:11.34	-31:55:54.5	HIP 99150	12.91
2026-04-09 12:00	20:07:12.06	-31:56:01.4	HIP 99150	12.92
2026-04-10 00:00	20:07:12.74	-31:56:08.5	HIP 99150	12.94
2026-04-10 12:00	20:07:13.40	-31:56:15.6	HIP 99150	12.97
2026-04-11 00:00	20:07:14.03	-31:56:22.8	HIP 99150	13.01
2026-04-11 12:00	20:07:14.64	-31:56:30.0	HIP 99150	13.05
2026-04-12 00:00	20:07:15.22	-31:56:37.4	HIP 99150	13.10
2026-04-12 12:00	20:07:15.77	-31:56:44.9	HIP 99150	13.15
2026-04-13 00:00	20:07:16.29	-31:56:52.4	HIP 99150	13.21
2026-04-13 12:00	20:07:16.79	-31:57:00.0	HIP 99150	13.28
2026-04-14 00:00	20:07:17.25	-31:57:07.7	HIP 99150	13.35
2026-04-14 12:00	20:07:17.69	-31:57:15.5	HIP 99150	13.42
2026-04-15 00:00	20:07:18.11	-31:57:23.4	HIP 99150	13.51
2026-04-15 12:00	20:07:18.49	-31:57:31.4	HIP 99150	13.59
2026-04-16 00:00	20:07:18.85	-31:57:39.4	HIP 99150	13.68