メタデータ

項目	値
Designation	C/1969 Y1 (Bennett)
Type	C
Perihelion (tp_cal, UTC)	1970-03-20T01:05:24.547200Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:29:19Z
Obs used	529
NEO	-
M1	4.600
K1	12.000
PC	-

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	1970-04-12.0000000
e	0.99629328
q (au)	0.537620
a (au)	145.039330
i (deg)	90.039811
Ω (om, deg)	224.657683
ω (w, deg)	354.149089
M (ma, deg)	0.012952

等級

散乱 + 全体線形

$$ M_a = (4.085 + 3.365\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	4.085
n	3.365
gf	0.800
gb	-0.500
k	1.000
δ90	1.000

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
1969-12-28	1970-03-20	+3.0975	+0.766
1970-03-20	1970-04-13	-4.8648	-1.069
1970-04-13	1970-05-01	+0.0535	-0.380
1970-05-01	1970-11-20	+1.8732	-0.612

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)
2026-03-26 00:00	02:28:21.41	+29:19:58.5	HIP 11579	19.60
2026-03-26 12:00	02:28:22.77	+29:20:00.6	HIP 11579	19.46
2026-03-27 00:00	02:28:24.15	+29:20:02.8	HIP 11579	19.32
2026-03-27 12:00	02:28:25.53	+29:20:05.1	HIP 11579	19.18
2026-03-28 00:00	02:28:26.92	+29:20:07.4	HIP 11579	19.05
2026-03-28 12:00	02:28:28.32	+29:20:09.8	HIP 11579	18.92
2026-03-29 00:00	02:28:29.73	+29:20:12.3	HIP 11579	18.80
2026-03-29 12:00	02:28:31.14	+29:20:14.9	HIP 11579	18.68
2026-03-30 00:00	02:28:32.56	+29:20:17.5	HIP 11579	18.56
2026-03-30 12:00	02:28:33.99	+29:20:20.3	HIP 11579	18.46
2026-03-31 00:00	02:28:35.42	+29:20:23.0	HIP 11579	18.35
2026-03-31 12:00	02:28:36.86	+29:20:25.9	HIP 11579	18.25
2026-04-01 00:00	02:28:38.31	+29:20:28.8	HIP 11579	18.16
2026-04-01 12:00	02:28:39.77	+29:20:31.8	HIP 11579	18.07
2026-04-02 00:00	02:28:41.23	+29:20:34.9	HIP 11579	17.99
2026-04-02 12:00	02:28:42.69	+29:20:38.0	HIP 11579	17.91
2026-04-03 00:00	02:28:44.17	+29:20:41.2	HIP 11579	17.85
2026-04-03 12:00	02:28:45.65	+29:20:44.5	HIP 11579	17.78
2026-04-04 00:00	02:28:47.13	+29:20:47.9	HIP 11579	17.73
2026-04-04 12:00	02:28:48.62	+29:20:51.3	HIP 11579	17.68
2026-04-05 00:00	02:28:50.12	+29:20:54.8	HIP 11579	17.63
2026-04-05 12:00	02:28:51.62	+29:20:58.3	HIP 11579	17.60
2026-04-06 00:00	02:28:53.13	+29:21:02.0	HIP 11579	17.57
2026-04-06 12:00	02:28:54.65	+29:21:05.6	HIP 11579	17.54
2026-04-07 00:00	02:28:56.17	+29:21:09.4	HIP 11579	17.53
2026-04-07 12:00	02:28:57.69	+29:21:13.2	HIP 11579	17.52
2026-04-08 00:00	02:28:59.22	+29:21:17.1	HIP 11579	17.52
2026-04-08 12:00	02:29:00.76	+29:21:21.1	HIP 11579	17.53
2026-04-09 00:00	02:29:02.30	+29:21:25.1	HIP 11579	17.54
2026-04-09 12:00	02:29:03.85	+29:21:29.2	HIP 11579	17.57
2026-04-10 00:00	02:29:05.40	+29:21:33.4	HIP 11579	17.60
2026-04-10 12:00	02:29:06.95	+29:21:37.6	HIP 11579	17.63
2026-04-11 00:00	02:29:08.51	+29:21:41.9	HIP 11579	17.68
2026-04-11 12:00	02:29:10.08	+29:21:46.2	HIP 11579	17.73
2026-04-12 00:00	02:29:11.65	+29:21:50.6	HIP 11579	17.80
2026-04-12 12:00	02:29:13.22	+29:21:55.1	HIP 11579	17.86
2026-04-13 00:00	02:29:14.80	+29:21:59.7	HIP 11579	17.94
2026-04-13 12:00	02:29:16.38	+29:22:04.3	HIP 11579	18.03
2026-04-14 00:00	02:29:17.96	+29:22:09.0	HIP 11579	18.12
2026-04-14 12:00	02:29:19.55	+29:22:13.7	HIP 11579	18.22
2026-04-15 00:00	02:29:21.15	+29:22:18.5	HIP 11579	18.32
2026-04-15 12:00	02:29:22.74	+29:22:23.4	HIP 11579	18.44
2026-04-16 00:00	02:29:24.34	+29:22:28.3	HIP 11579	18.56