メタデータ

項目	値
Designation	C/2021 S3 (PANSTARRS)
Type	C
Perihelion (tp_cal, UTC)	2024-02-14T17:02:55.976640Z
Orbit solution date (soln_date, UTC)	2026-01-07T15:42:41Z
Obs used	4855
NEO	-
M1	10.700
K1	4.500
PC	-
Discovery observation (MPC, UTC)	2021-09-24T13:27:42.969600Z
Discovery magnitude (MPC)	20.17 i
Discovery observatory (MPC)	F52 · Pan-STARRS 2, Haleakala

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2024-03-19.0000000
e	1.00024544
q (au)	1.320205
a (au)	-5378.855450
i (deg)	58.532818
Ω (om, deg)	215.620806
ω (w, deg)	6.853898
M (ma, deg)	0.000083

等級

散乱 + 全体線形

$$ M_a = (9.812 + 3.233\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	9.812
n	3.233
gf	0.991
gb	-0.915
k	0.980
δ90	9.892

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
2020-12-06	2023-05-02	+6.6905	-5.821
2023-05-02	2024-02-14	-0.5524	-1.219
2024-02-14	2024-11-13	+1.6113	-0.826
2024-11-13	2025-12-27	+6.1192	-3.554

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	00:08:10.86	+34:05:45.3	HIP 725	19.17
2026-05-12 12:00	00:08:22.36	+34:07:30.3	HIP 725	16.47
2026-05-13 00:00	00:08:33.78	+34:09:15.5	HIP 725	13.88
2026-05-13 12:00	00:08:45.12	+34:11:00.7	HIP 725	11.46
2026-05-14 00:00	00:08:56.37	+34:12:46.1	HIP 725	9.33
2026-05-14 12:00	00:09:07.54	+34:14:31.6	HIP 725	7.73
2026-05-15 00:00	00:09:18.63	+34:16:17.1	HIP 725	7.01
2026-05-15 12:00	00:09:29.63	+34:18:02.8	HIP 725	7.41
2026-05-16 00:00	00:09:40.54	+34:19:48.5	HIP 725	8.77
2026-05-16 12:00	00:09:51.37	+34:21:34.3	HIP 725	10.71
2026-05-17 00:00	00:10:02.11	+34:23:20.1	HIP 725	12.98
2026-05-17 12:00	00:10:12.76	+34:25:06.0	HIP 725	15.41
2026-05-18 00:00	00:10:23.33	+34:26:52.0	HIP 725	17.94
2026-05-18 12:00	00:10:33.80	+34:28:38.0	HIP 725	20.52
2026-05-19 00:00	00:10:44.19	+34:30:24.1	HIP 725	23.13
2026-05-19 12:00	00:10:54.48	+34:32:10.2	HIP 725	25.76
2026-05-20 00:00	00:11:04.69	+34:33:56.3	HIP 725	28.39
2026-05-20 12:00	00:11:14.80	+34:35:42.4	HIP 725	31.03
2026-05-21 00:00	00:11:24.82	+34:37:28.6	HIP 725	33.67
2026-05-21 12:00	00:11:34.75	+34:39:14.7	HIP 725	36.30
2026-05-22 00:00	00:11:44.59	+34:41:00.9	HIP 725	38.92
2026-05-22 12:00	00:11:54.33	+34:42:47.0	HIP 1048	37.56
2026-05-23 00:00	00:12:03.98	+34:44:33.2	HIP 1048	35.19
2026-05-23 12:00	00:12:13.54	+34:46:19.3	HIP 1048	32.86
2026-05-24 00:00	00:12:23.00	+34:48:05.4	HIP 1048	30.60
2026-05-24 12:00	00:12:32.37	+34:49:51.5	HIP 1048	28.40
2026-05-25 00:00	00:12:41.64	+34:51:37.6	HIP 1048	26.29
2026-05-25 12:00	00:12:50.81	+34:53:23.6	HIP 1048	24.26
2026-05-26 00:00	00:12:59.89	+34:55:09.5	HIP 1048	22.36
2026-05-26 12:00	00:13:08.88	+34:56:55.5	HIP 1048	20.60
2026-05-27 00:00	00:13:17.76	+34:58:41.3	HIP 1048	19.01
2026-05-27 12:00	00:13:26.55	+35:00:27.1	HIP 1048	17.64
2026-05-28 00:00	00:13:35.24	+35:02:12.9	HIP 1048	16.54
2026-05-28 12:00	00:13:43.84	+35:03:58.5	HIP 1048	15.75
2026-05-29 00:00	00:13:52.33	+35:05:44.1	HIP 1048	15.32
2026-05-29 12:00	00:14:00.73	+35:07:29.6	HIP 1048	15.26
2026-05-30 00:00	00:14:09.02	+35:09:15.0	HIP 1048	15.58
2026-05-30 12:00	00:14:17.22	+35:11:00.3	HIP 1137	14.10
2026-05-31 00:00	00:14:25.31	+35:12:45.6	HIP 1137	12.57
2026-05-31 12:00	00:14:33.30	+35:14:30.7	HIP 1137	11.35
2026-06-01 00:00	00:14:41.20	+35:16:15.7	HIP 1137	10.52
2026-06-01 12:00	00:14:48.99	+35:18:00.6	HIP 1137	10.18
2026-06-02 00:00	00:14:56.68	+35:19:45.3	HIP 1137	10.36