メタデータ

項目	値
Designation	C/2024 R4 (PANSTARRS)
Type	C
Perihelion (tp_cal, UTC)	2027-10-26T17:08:08.805120Z
Orbit solution date (soln_date, UTC)	2026-09-08T09:12:17Z
Obs used	1890
NEO	-
M1	6.100
K1	7.750
PC	0.030
Discovery observation (MPC, UTC)	2024-09-11T08:54:09.475200Z
Discovery magnitude (MPC)	21.20 w
Discovery observatory (MPC)	F51 · Pan-STARRS 1, Haleakala

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2026-01-26.0000000
e	1.00248286
q (au)	4.408614
a (au)	-1775.618743
i (deg)	95.374064
Ω (om, deg)	345.941931
ω (w, deg)	109.004521
M (ma, deg)	-0.008414

等級

散乱 + 全体線形

$$ M_a = (4.336 + 5.624\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	4.336
n	5.624
gf	1.000
gb	-0.776
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
2024-07-03	2025-04-28	+27.3028	-24.818
2025-04-28	2025-10-29	+4.6319	-4.058
2025-10-29	2026-09-26	-3.2276	+2.535

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)
2026-09-20 00:00	20:10:07.58	+48:24:04.6	HIP 99405	11.09
2026-09-20 12:00	20:09:33.44	+48:21:27.0	HIP 99405	12.57
2026-09-21 00:00	20:08:59.60	+48:18:47.4	HIP 99405	16.41
2026-09-21 12:00	20:08:26.08	+48:16:06.0	HIP 99112	12.20
2026-09-22 00:00	20:07:52.88	+48:13:22.7	HIP 99112	6.07
2026-09-22 12:00	20:07:19.98	+48:10:37.7	HIP 99112	0.86
2026-09-23 00:00	20:06:47.41	+48:07:50.9	HIP 99112	6.29
2026-09-23 12:00	20:06:15.15	+48:05:02.3	HIP 99112	12.34
2026-09-24 00:00	20:05:43.22	+48:02:12.1	HIP 98858	16.98
2026-09-24 12:00	20:05:11.60	+47:59:20.3	HIP 98858	16.11
2026-09-25 00:00	20:04:40.31	+47:56:26.9	HIP 98858	17.44
2026-09-25 12:00	20:04:09.35	+47:53:31.9	HIP 98858	20.51
2026-09-26 00:00	20:03:38.71	+47:50:35.4	HIP 98917	23.18
2026-09-26 12:00	20:03:08.39	+47:47:37.4	HIP 98917	24.91
2026-09-27 00:00	20:02:38.41	+47:44:38.0	HIP 98450	26.98
2026-09-27 12:00	20:02:08.75	+47:41:37.2	HIP 98450	24.22
2026-09-28 00:00	20:01:39.43	+47:38:35.1	HIP 98450	22.70
2026-09-28 12:00	20:01:10.44	+47:35:31.6	HIP 98450	22.64
2026-09-29 00:00	20:00:41.78	+47:32:26.9	HIP 98345	21.41
2026-09-29 12:00	20:00:13.45	+47:29:20.9	HIP 98345	15.72
2026-09-30 00:00	19:59:45.46	+47:26:13.7	HIP 98345	10.08
2026-09-30 12:00	19:59:17.80	+47:23:05.3	HIP 98345	4.57
2026-10-01 00:00	19:58:50.48	+47:19:55.8	HIP 98345	1.89
2026-10-01 12:00	19:58:23.49	+47:16:45.3	HIP 98345	6.98
2026-10-02 00:00	19:57:56.84	+47:13:33.7	HIP 98345	12.45
2026-10-02 12:00	19:57:30.53	+47:10:21.0	HIP 98071	17.14
2026-10-03 00:00	19:57:04.56	+47:07:07.5	HIP 98071	12.12
2026-10-03 12:00	19:56:38.93	+47:03:52.9	HIP 98071	7.79
2026-10-04 00:00	19:56:13.64	+47:00:37.5	HIP 98071	5.83
2026-10-04 12:00	19:55:48.68	+46:57:21.3	HIP 98071	8.10
2026-10-05 00:00	19:55:24.07	+46:54:04.2	HIP 98064	10.37
2026-10-05 12:00	19:54:59.80	+46:50:46.4	HIP 98064	10.48
2026-10-06 00:00	19:54:35.87	+46:47:27.9	HIP 98028	9.75
2026-10-06 12:00	19:54:12.28	+46:44:08.6	HIP 98028	11.08
2026-10-07 00:00	19:53:49.03	+46:40:48.8	HIP 98028	14.27
2026-10-07 12:00	19:53:26.12	+46:37:28.3	HIP 98028	18.35
2026-10-08 00:00	19:53:03.55	+46:34:07.2	HIP 98028	22.82
2026-10-08 12:00	19:52:41.32	+46:30:45.7	HIP 98028	27.47
2026-10-09 00:00	19:52:19.44	+46:27:23.6	HIP 98028	32.21
2026-10-09 12:00	19:51:57.89	+46:24:01.1	HIP 97486	32.35
2026-10-10 00:00	19:51:36.69	+46:20:38.2	HIP 97486	28.62
2026-10-10 12:00	19:51:15.82	+46:17:14.9	HIP 97486	25.39
2026-10-11 00:00	19:50:55.29	+46:13:51.3	HIP 97486	22.82