メタデータ

項目	値
Designation	285P/LINEAR
Type	P
Perihelion (tp_cal, UTC)	2023-01-12T20:28:47.072640Z
Orbit solution date (soln_date, UTC)	2024-06-06T23:12:48Z
Obs used	933
NEO	-
M1	13.600
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)	2020-02-29.0000000
e	0.61787770
q (au)	1.723017
a (au)	4.509072
i (deg)	25.023386
Ω (om, deg)	185.483345
ω (w, deg)	178.401291
M (ma, deg)	252.033734

等級

散乱 + 全体線形

$$ M_a = (15.549 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	15.549
n	2.000
gf	1.000
gb	-1.000
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
2022-06-28	2022-08-13	+85.0046	-30.978
2022-08-13	2023-01-09	-1.4071	+0.571

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	10:34:26.40	+00:00:39.6	HIP 51791	22.47
2026-05-12 12:00	10:34:26.34	+00:01:48.7	HIP 51791	23.57
2026-05-13 00:00	10:34:26.42	+00:02:57.0	HIP 51791	24.65
2026-05-13 12:00	10:34:26.64	+00:04:04.3	HIP 51791	25.70
2026-05-14 00:00	10:34:26.99	+00:05:10.7	HIP 51791	26.74
2026-05-14 12:00	10:34:27.49	+00:06:16.1	HIP 51791	27.76
2026-05-15 00:00	10:34:28.12	+00:07:20.7	HIP 51791	28.76
2026-05-15 12:00	10:34:28.90	+00:08:24.3	HIP 51791	29.75
2026-05-16 00:00	10:34:29.81	+00:09:27.1	HIP 51791	30.72
2026-05-16 12:00	10:34:30.85	+00:10:28.9	HIP 51791	31.67
2026-05-17 00:00	10:34:32.04	+00:11:29.8	HIP 51791	32.61
2026-05-17 12:00	10:34:33.36	+00:12:29.7	HIP 51791	33.54
2026-05-18 00:00	10:34:34.82	+00:13:28.7	HIP 51791	34.45
2026-05-18 12:00	10:34:36.41	+00:14:26.8	HIP 51791	35.35
2026-05-19 00:00	10:34:38.14	+00:15:24.0	HIP 51895	34.37
2026-05-19 12:00	10:34:40.00	+00:16:20.2	HIP 51895	33.36
2026-05-20 00:00	10:34:42.00	+00:17:15.6	HIP 51895	32.35
2026-05-20 12:00	10:34:44.14	+00:18:09.9	HIP 51895	31.32
2026-05-21 00:00	10:34:46.40	+00:19:03.4	HIP 51895	30.28
2026-05-21 12:00	10:34:48.80	+00:19:55.9	HIP 51895	29.23
2026-05-22 00:00	10:34:51.34	+00:20:47.5	HIP 51895	28.17
2026-05-22 12:00	10:34:54.00	+00:21:38.2	HIP 51895	27.10
2026-05-23 00:00	10:34:56.80	+00:22:27.9	HIP 51895	26.02
2026-05-23 12:00	10:34:59.73	+00:23:16.8	HIP 51895	24.92
2026-05-24 00:00	10:35:02.79	+00:24:04.7	HIP 51895	23.82
2026-05-24 12:00	10:35:05.98	+00:24:51.6	HIP 51895	22.70
2026-05-25 00:00	10:35:09.30	+00:25:37.7	HIP 51895	21.57
2026-05-25 12:00	10:35:12.74	+00:26:22.8	HIP 51895	20.43
2026-05-26 00:00	10:35:16.32	+00:27:07.0	HIP 51895	19.28
2026-05-26 12:00	10:35:20.02	+00:27:50.3	HIP 51895	18.12
2026-05-27 00:00	10:35:23.85	+00:28:32.7	HIP 51895	16.96
2026-05-27 12:00	10:35:27.81	+00:29:14.1	HIP 51895	15.79
2026-05-28 00:00	10:35:31.90	+00:29:54.6	HIP 51895	14.61
2026-05-28 12:00	10:35:36.10	+00:30:34.3	HIP 51895	13.44
2026-05-29 00:00	10:35:40.44	+00:31:13.0	HIP 51895	12.27
2026-05-29 12:00	10:35:44.90	+00:31:50.8	HIP 51895	11.12
2026-05-30 00:00	10:35:49.48	+00:32:27.7	HIP 51895	10.00
2026-05-30 12:00	10:35:54.19	+00:33:03.7	HIP 51895	8.92
2026-05-31 00:00	10:35:59.01	+00:33:38.7	HIP 51895	7.93
2026-05-31 12:00	10:36:03.97	+00:34:12.9	HIP 51895	7.07
2026-06-01 00:00	10:36:09.04	+00:34:46.2	HIP 51895	6.39
2026-06-01 12:00	10:36:14.23	+00:35:18.5	HIP 51895	5.98
2026-06-02 00:00	10:36:19.54	+00:35:50.0	HIP 51895	5.92