メタデータ

項目	値
Designation	404P/Bressi
Type	P
Perihelion (tp_cal, UTC)	2023-10-24T23:24:20.805120Z
Orbit solution date (soln_date, UTC)	2026-03-17T15:12:47Z
Obs used	785
NEO	-
M1	10.000
K1	10.250
PC	0.030

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2022-08-30.0000000
e	0.13286937
q (au)	4.135875
a (au)	4.769611
i (deg)	9.738129
Ω (om, deg)	260.353617
ω (w, deg)	167.853131
M (ma, deg)	320.167622

等級

散乱 + 全体線形

$$ M_a = (6.383 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	6.383
n	6.000
gf	0.948
gb	-0.845
k	1.000
δ90	8.833

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
2020-06-17	2023-10-23	+4.6292	-2.683
2023-11-08	2026-03-14	+0.5720	-0.604

log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)

天体暦

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-09-20 00:00	11:57:25.68	-08:21:00.7	HIP 58333	6.79
2026-09-20 12:00	11:57:52.54	-08:23:46.6	HIP 58333	7.44
2026-09-21 00:00	11:58:19.40	-08:26:32.6	HIP 58331	10.56
2026-09-21 12:00	11:58:46.26	-08:29:18.9	HIP 58331	15.48
2026-09-22 00:00	11:59:13.13	-08:32:05.5	HIP 58331	21.71
2026-09-22 12:00	11:59:40.00	-08:34:52.2	HIP 58331	28.40
2026-09-23 00:00	12:00:06.86	-08:37:39.2	HIP 58633	34.30
2026-09-23 12:00	12:00:33.73	-08:40:26.4	HIP 58633	33.53
2026-09-24 00:00	12:01:00.59	-08:43:13.8	HIP 58633	34.29
2026-09-24 12:00	12:01:27.46	-08:46:01.5	HIP 58633	36.49
2026-09-25 00:00	12:01:54.32	-08:48:49.3	HIP 58633	39.90
2026-09-25 12:00	12:02:21.18	-08:51:37.4	HIP 58865	41.63
2026-09-26 00:00	12:02:48.03	-08:54:25.6	HIP 58865	35.11
2026-09-26 12:00	12:03:14.89	-08:57:14.1	HIP 58865	28.91
2026-09-27 00:00	12:03:41.74	-09:00:02.7	HIP 58865	23.30
2026-09-27 12:00	12:04:08.58	-09:02:51.5	HIP 58865	18.80
2026-09-28 00:00	12:04:35.43	-09:05:40.5	HIP 58936	14.88
2026-09-28 12:00	12:05:02.26	-09:08:29.7	HIP 58936	10.06
2026-09-29 00:00	12:05:29.10	-09:11:19.1	HIP 58936	9.19
2026-09-29 12:00	12:05:55.92	-09:14:08.6	HIP 58936	13.08
2026-09-30 00:00	12:06:22.74	-09:16:58.4	HIP 59060	9.19
2026-09-30 12:00	12:06:49.56	-09:19:48.3	HIP 59060	5.02
2026-10-01 00:00	12:07:16.37	-09:22:38.3	HIP 59060	8.34
2026-10-01 12:00	12:07:43.17	-09:25:28.5	HIP 59060	14.74
2026-10-02 00:00	12:08:09.96	-09:28:18.9	HIP 59060	21.64
2026-10-02 12:00	12:08:36.74	-09:31:09.5	HIP 59060	28.69
2026-10-03 00:00	12:09:03.52	-09:34:00.1	HIP 59359	26.05
2026-10-03 12:00	12:09:30.28	-09:36:51.0	HIP 59359	21.64
2026-10-04 00:00	12:09:57.04	-09:39:41.9	HIP 59359	19.02
2026-10-04 12:00	12:10:23.78	-09:42:33.0	HIP 59359	18.93
2026-10-05 00:00	12:10:50.52	-09:45:24.3	HIP 59359	21.41
2026-10-05 12:00	12:11:17.24	-09:48:15.7	HIP 59367	25.45
2026-10-06 00:00	12:11:43.95	-09:51:07.2	HIP 59367	30.55
2026-10-06 12:00	12:12:10.65	-09:53:58.8	HIP 59625	31.53
2026-10-07 00:00	12:12:37.33	-09:56:50.5	HIP 59625	29.95
2026-10-07 12:00	12:13:04.00	-09:59:42.3	HIP 59625	30.05
2026-10-08 00:00	12:13:30.66	-10:02:34.3	HIP 59720	29.32
2026-10-08 12:00	12:13:57.30	-10:05:26.3	HIP 59750	22.31
2026-10-09 00:00	12:14:23.93	-10:08:18.5	HIP 59750	15.41
2026-10-09 12:00	12:14:50.53	-10:11:10.7	HIP 59750	8.90
2026-10-10 00:00	12:15:17.12	-10:14:03.0	HIP 59750	4.83
2026-10-10 12:00	12:15:43.70	-10:16:55.4	HIP 59750	8.33
2026-10-11 00:00	12:16:10.25	-10:19:47.9	HIP 59750	14.74