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)
2026-09-20 00:00	02:32:29.80	+29:53:00.5	HIP 11869	9.60
2026-09-20 12:00	02:32:28.57	+29:52:59.1	HIP 11869	9.85
2026-09-21 00:00	02:32:27.32	+29:52:57.6	HIP 11869	10.09
2026-09-21 12:00	02:32:26.07	+29:52:56.0	HIP 11869	10.34
2026-09-22 00:00	02:32:24.81	+29:52:54.4	HIP 11869	10.60
2026-09-22 12:00	02:32:23.54	+29:52:52.6	HIP 11869	10.85
2026-09-23 00:00	02:32:22.26	+29:52:50.8	HIP 11869	11.11
2026-09-23 12:00	02:32:20.97	+29:52:48.9	HIP 11869	11.38
2026-09-24 00:00	02:32:19.67	+29:52:47.0	HIP 11869	11.65
2026-09-24 12:00	02:32:18.36	+29:52:44.9	HIP 11869	11.92
2026-09-25 00:00	02:32:17.04	+29:52:42.8	HIP 11869	12.19
2026-09-25 12:00	02:32:15.71	+29:52:40.6	HIP 11869	12.47
2026-09-26 00:00	02:32:14.37	+29:52:38.3	HIP 11869	12.74
2026-09-26 12:00	02:32:13.03	+29:52:36.0	HIP 11869	13.03
2026-09-27 00:00	02:32:11.67	+29:52:33.6	HIP 11869	13.31
2026-09-27 12:00	02:32:10.31	+29:52:31.0	HIP 11869	13.60
2026-09-28 00:00	02:32:08.94	+29:52:28.5	HIP 11869	13.89
2026-09-28 12:00	02:32:07.56	+29:52:25.8	HIP 11869	14.18
2026-09-29 00:00	02:32:06.17	+29:52:23.1	HIP 11869	14.48
2026-09-29 12:00	02:32:04.77	+29:52:20.2	HIP 11869	14.78
2026-09-30 00:00	02:32:03.36	+29:52:17.3	HIP 11869	15.08
2026-09-30 12:00	02:32:01.95	+29:52:14.4	HIP 11869	15.38
2026-10-01 00:00	02:32:00.52	+29:52:11.3	HIP 11869	15.69
2026-10-01 12:00	02:31:59.09	+29:52:08.2	HIP 11869	16.00
2026-10-02 00:00	02:31:57.66	+29:52:05.0	HIP 11869	16.31
2026-10-02 12:00	02:31:56.21	+29:52:01.7	HIP 11869	16.62
2026-10-03 00:00	02:31:54.75	+29:51:58.3	HIP 11869	16.93
2026-10-03 12:00	02:31:53.29	+29:51:54.9	HIP 11869	17.25
2026-10-04 00:00	02:31:51.82	+29:51:51.4	HIP 11869	17.57
2026-10-04 12:00	02:31:50.35	+29:51:47.8	HIP 11869	17.89
2026-10-05 00:00	02:31:48.86	+29:51:44.1	HIP 11869	18.21
2026-10-05 12:00	02:31:47.37	+29:51:40.4	HIP 11869	18.54
2026-10-06 00:00	02:31:45.87	+29:51:36.6	HIP 11869	18.87
2026-10-06 12:00	02:31:44.37	+29:51:32.7	HIP 11869	19.20
2026-10-07 00:00	02:31:42.85	+29:51:28.7	HIP 11869	19.53
2026-10-07 12:00	02:31:41.34	+29:51:24.7	HIP 11869	19.86
2026-10-08 00:00	02:31:39.81	+29:51:20.6	HIP 11869	20.20
2026-10-08 12:00	02:31:38.28	+29:51:16.4	HIP 11869	20.53
2026-10-09 00:00	02:31:36.74	+29:51:12.1	HIP 11869	20.87
2026-10-09 12:00	02:31:35.19	+29:51:07.8	HIP 11869	21.21
2026-10-10 00:00	02:31:33.64	+29:51:03.4	HIP 11869	21.55
2026-10-10 12:00	02:31:32.08	+29:50:58.9	HIP 11869	21.90
2026-10-11 00:00	02:31:30.52	+29:50:54.3	HIP 11869	22.24