メタデータ

項目	値
Designation	C/2021 S3 (PANSTARRS)
Type	C
Perihelion (tp_cal, UTC)	2024-02-14T17:02:56.019840Z
Orbit solution date (soln_date, UTC)	2026-07-28T14:12:16Z
Obs used	4867
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	1.00024547
q (au)	1.320205
a (au)	-5378.325711
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)
2026-07-29 00:00	00:16:50.42	+37:56:22.7	HIP 1411	26.06
2026-07-29 12:00	00:16:44.39	+37:57:06.4	HIP 1411	27.20
2026-07-30 00:00	00:16:38.25	+37:57:49.1	HIP 1411	28.35
2026-07-30 12:00	00:16:31.99	+37:58:30.9	HIP 1411	29.53
2026-07-31 00:00	00:16:25.62	+37:59:11.7	HIP 1411	30.72
2026-07-31 12:00	00:16:19.13	+37:59:51.5	HIP 1411	31.93
2026-08-01 00:00	00:16:12.52	+38:00:30.4	HIP 1411	33.15
2026-08-01 12:00	00:16:05.80	+38:01:08.2	HIP 1411	34.40
2026-08-02 00:00	00:15:58.97	+38:01:45.0	HIP 1411	35.65
2026-08-02 12:00	00:15:52.02	+38:02:20.8	HIP 1411	36.93
2026-08-03 00:00	00:15:44.96	+38:02:55.7	HIP 1411	38.22
2026-08-03 12:00	00:15:37.79	+38:03:29.4	HIP 1411	39.52
2026-08-04 00:00	00:15:30.50	+38:04:02.2	HIP 1030	38.76
2026-08-04 12:00	00:15:23.10	+38:04:33.9	HIP 1030	37.90
2026-08-05 00:00	00:15:15.60	+38:05:04.6	HIP 1030	37.05
2026-08-05 12:00	00:15:07.98	+38:05:34.2	HIP 1030	36.22
2026-08-06 00:00	00:15:00.25	+38:06:02.8	HIP 1030	35.42
2026-08-06 12:00	00:14:52.42	+38:06:30.3	HIP 1030	34.64
2026-08-07 00:00	00:14:44.48	+38:06:56.8	HIP 1030	33.90
2026-08-07 12:00	00:14:36.42	+38:07:22.1	HIP 1030	33.19
2026-08-08 00:00	00:14:28.27	+38:07:46.4	HIP 1030	32.52
2026-08-08 12:00	00:14:20.00	+38:08:09.6	HIP 1030	31.90
2026-08-09 00:00	00:14:11.63	+38:08:31.7	HIP 1030	31.33
2026-08-09 12:00	00:14:03.15	+38:08:52.6	HIP 1030	30.82
2026-08-10 00:00	00:13:54.58	+38:09:12.5	HIP 1030	30.37
2026-08-10 12:00	00:13:45.89	+38:09:31.2	HIP 1030	29.98
2026-08-11 00:00	00:13:37.11	+38:09:48.9	HIP 1030	29.67
2026-08-11 12:00	00:13:28.22	+38:10:05.3	HIP 1030	29.44
2026-08-12 00:00	00:13:19.23	+38:10:20.7	HIP 1030	29.29
2026-08-12 12:00	00:13:10.15	+38:10:34.9	HIP 1030	29.23
2026-08-13 00:00	00:13:00.96	+38:10:47.9	HIP 1030	29.26
2026-08-13 12:00	00:12:51.68	+38:10:59.8	HIP 1030	29.38
2026-08-14 00:00	00:12:42.30	+38:11:10.6	HIP 1030	29.60
2026-08-14 12:00	00:12:32.82	+38:11:20.1	HIP 1030	29.91
2026-08-15 00:00	00:12:23.25	+38:11:28.5	HIP 823	30.21
2026-08-15 12:00	00:12:13.58	+38:11:35.7	HIP 823	28.47
2026-08-16 00:00	00:12:03.83	+38:11:41.8	HIP 823	26.74
2026-08-16 12:00	00:11:53.98	+38:11:46.6	HIP 823	25.04
2026-08-17 00:00	00:11:44.04	+38:11:50.3	HIP 823	23.37
2026-08-17 12:00	00:11:34.01	+38:11:52.8	HIP 823	21.74
2026-08-18 00:00	00:11:23.90	+38:11:54.1	HIP 823	20.17
2026-08-18 12:00	00:11:13.69	+38:11:54.1	HIP 823	18.68
2026-08-19 00:00	00:11:03.40	+38:11:53.0	HIP 823	17.30