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	9.884

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	+6.6906	-5.821
2023-05-02	2024-02-14	-0.5527	-1.219
2024-02-14	2024-11-13	+1.6110	-0.826
2024-11-13	2025-12-27	+6.1193	-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)
2026-06-01 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
2026-06-02 12:00	00:15:04.26	+35:21:30.0	HIP 1137	11.03
2026-06-03 00:00	00:15:11.74	+35:23:14.5	HIP 1137	12.10
2026-06-03 12:00	00:15:19.12	+35:24:58.8	HIP 1137	13.46
2026-06-04 00:00	00:15:26.40	+35:26:43.0	HIP 1137	15.02
2026-06-04 12:00	00:15:33.57	+35:28:27.1	HIP 1137	16.74
2026-06-05 00:00	00:15:40.63	+35:30:11.0	HIP 1137	18.54
2026-06-05 12:00	00:15:47.59	+35:31:54.8	HIP 1137	20.42
2026-06-06 00:00	00:15:54.44	+35:33:38.3	HIP 1137	22.34
2026-06-06 12:00	00:16:01.19	+35:35:21.7	HIP 1137	24.29
2026-06-07 00:00	00:16:07.83	+35:37:05.0	HIP 1137	26.25
2026-06-07 12:00	00:16:14.36	+35:38:48.0	HIP 1297	28.12
2026-06-08 00:00	00:16:20.78	+35:40:30.8	HIP 1297	29.86
2026-06-08 12:00	00:16:27.10	+35:42:13.5	HIP 1492	31.32
2026-06-09 00:00	00:16:33.30	+35:43:55.9	HIP 1492	29.33
2026-06-09 12:00	00:16:39.40	+35:45:38.1	HIP 1492	27.39
2026-06-10 00:00	00:16:45.39	+35:47:20.1	HIP 1492	25.50
2026-06-10 12:00	00:16:51.26	+35:49:01.8	HIP 1492	23.67
2026-06-11 00:00	00:16:57.03	+35:50:43.4	HIP 1492	21.90
2026-06-11 12:00	00:17:02.68	+35:52:24.6	HIP 1492	20.20
2026-06-12 00:00	00:17:08.22	+35:54:05.7	HIP 1492	18.60
2026-06-12 12:00	00:17:13.65	+35:55:46.5	HIP 1492	17.12
2026-06-13 00:00	00:17:18.96	+35:57:27.0	HIP 1492	15.77
2026-06-13 12:00	00:17:24.17	+35:59:07.2	HIP 1492	14.60
2026-06-14 00:00	00:17:29.25	+36:00:47.2	HIP 1492	13.64
2026-06-14 12:00	00:17:34.23	+36:02:26.8	HIP 1492	12.92
2026-06-15 00:00	00:17:39.09	+36:04:06.2	HIP 1492	12.49
2026-06-15 12:00	00:17:43.83	+36:05:45.3	HIP 1492	12.37
2026-06-16 00:00	00:17:48.46	+36:07:24.0	HIP 1492	12.55
2026-06-16 12:00	00:17:52.97	+36:09:02.5	HIP 1492	13.03
2026-06-17 00:00	00:17:57.36	+36:10:40.6	HIP 1492	13.75
2026-06-17 12:00	00:18:01.64	+36:12:18.4	HIP 1492	14.69
2026-06-18 00:00	00:18:05.80	+36:13:55.8	HIP 1492	15.78
2026-06-18 12:00	00:18:09.84	+36:15:32.9	HIP 1492	17.01
2026-06-19 00:00	00:18:13.77	+36:17:09.6	HIP 1403	17.86
2026-06-19 12:00	00:18:17.58	+36:18:46.0	HIP 1403	16.84
2026-06-20 00:00	00:18:21.27	+36:20:22.0	HIP 1403	15.95
2026-06-20 12:00	00:18:24.84	+36:21:57.6	HIP 1403	15.20
2026-06-21 00:00	00:18:28.29	+36:23:32.9	HIP 1403	14.60
2026-06-21 12:00	00:18:31.62	+36:25:07.7	HIP 1403	14.18
2026-06-22 00:00	00:18:34.84	+36:26:42.2	HIP 1403	13.94