メタデータ

項目	値
Designation	1P/Halley
Type	P
Perihelion (tp_cal, UTC)	1986-02-08T11:22:00.431040Z
Orbit solution date (soln_date, UTC)	2025-11-21T15:57:34Z
Obs used	8518
NEO	Yes
M1	5.500
K1	8.000
PC	0.030

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	1968-01-20.0000000
e	0.96793600
q (au)	0.574864
a (au)	17.928635
i (deg)	162.190530
Ω (om, deg)	59.098947
ω (w, deg)	112.241431
M (ma, deg)	274.382337

説明

最初に周期彗星として予報された彗星で、最古の記録は紀元前240年の中国『史記』に見られる。

等級

散乱 + 全体線形

$$ M_a = (3.661 + 3.876\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	3.661
n	3.876
gf	1.000
gb	-0.500
k	1.000
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
1981-12-02	1985-11-05	+6.7140	-0.431
1985-11-05	1986-01-28	+2.0297	+0.388
1986-02-15	1986-07-08	-2.7942	-0.455
1986-07-08	1987-12-12	+0.0819	-1.319
1987-12-12	2003-03-08	+3.7502	-4.319

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	08:09:16.21	+03:07:43.3	HIP 39872	14.06
2026-03-26 12:00	08:09:14.65	+03:08:01.9	HIP 39872	14.07
2026-03-27 00:00	08:09:13.12	+03:08:20.5	HIP 39872	14.10
2026-03-27 12:00	08:09:11.61	+03:08:39.0	HIP 39872	14.15
2026-03-28 00:00	08:09:10.13	+03:08:57.5	HIP 39872	14.22
2026-03-28 12:00	08:09:08.68	+03:09:16.0	HIP 39872	14.31
2026-03-29 00:00	08:09:07.26	+03:09:34.4	HIP 39872	14.41
2026-03-29 12:00	08:09:05.86	+03:09:52.8	HIP 39872	14.54
2026-03-30 00:00	08:09:04.49	+03:10:11.1	HIP 39872	14.67
2026-03-30 12:00	08:09:03.15	+03:10:29.4	HIP 39872	14.83
2026-03-31 00:00	08:09:01.84	+03:10:47.7	HIP 39872	14.99
2026-03-31 12:00	08:09:00.55	+03:11:05.9	HIP 39872	15.17
2026-04-01 00:00	08:08:59.29	+03:11:24.0	HIP 39872	15.37
2026-04-01 12:00	08:08:58.06	+03:11:42.1	HIP 39872	15.57
2026-04-02 00:00	08:08:56.86	+03:12:00.1	HIP 39872	15.78
2026-04-02 12:00	08:08:55.68	+03:12:18.1	HIP 39872	16.00
2026-04-03 00:00	08:08:54.53	+03:12:36.1	HIP 39872	16.23
2026-04-03 12:00	08:08:53.41	+03:12:54.0	HIP 39872	16.47
2026-04-04 00:00	08:08:52.32	+03:13:11.8	HIP 39872	16.72
2026-04-04 12:00	08:08:51.25	+03:13:29.5	HIP 39872	16.97
2026-04-05 00:00	08:08:50.21	+03:13:47.3	HIP 39872	17.22
2026-04-05 12:00	08:08:49.20	+03:14:04.9	HIP 39872	17.48
2026-04-06 00:00	08:08:48.22	+03:14:22.5	HIP 39872	17.75
2026-04-06 12:00	08:08:47.27	+03:14:40.0	HIP 39872	18.02
2026-04-07 00:00	08:08:46.34	+03:14:57.5	HIP 39872	18.29
2026-04-07 12:00	08:08:45.45	+03:15:14.9	HIP 39872	18.57
2026-04-08 00:00	08:08:44.58	+03:15:32.2	HIP 39872	18.84
2026-04-08 12:00	08:08:43.74	+03:15:49.5	HIP 39872	19.12
2026-04-09 00:00	08:08:42.92	+03:16:06.7	HIP 39872	19.40
2026-04-09 12:00	08:08:42.14	+03:16:23.8	HIP 39872	19.69
2026-04-10 00:00	08:08:41.38	+03:16:40.9	HIP 39872	19.97
2026-04-10 12:00	08:08:40.66	+03:16:57.9	HIP 39872	20.25
2026-04-11 00:00	08:08:39.96	+03:17:14.8	HIP 39872	20.54
2026-04-11 12:00	08:08:39.29	+03:17:31.6	HIP 39872	20.82
2026-04-12 00:00	08:08:38.64	+03:17:48.4	HIP 39872	21.10
2026-04-12 12:00	08:08:38.03	+03:18:05.1	HIP 39872	21.39
2026-04-13 00:00	08:08:37.44	+03:18:21.7	HIP 39872	21.67
2026-04-13 12:00	08:08:36.89	+03:18:38.3	HIP 39872	21.95
2026-04-14 00:00	08:08:36.36	+03:18:54.7	HIP 39872	22.23
2026-04-14 12:00	08:08:35.86	+03:19:11.1	HIP 39872	22.51
2026-04-15 00:00	08:08:35.39	+03:19:27.4	HIP 39872	22.79
2026-04-15 12:00	08:08:34.94	+03:19:43.6	HIP 39872	23.07
2026-04-16 00:00	08:08:34.53	+03:19:59.7	HIP 39872	23.34