メタデータ

項目	値
Designation	8P/Tuttle
Type	P
Perihelion (tp_cal, UTC)	2008-01-27T00:25:56.539200Z
Orbit solution date (soln_date, UTC)	2022-05-02T08:47:13Z
Obs used	1768
NEO	Yes
M1	14.600
K1	4.500
PC	-

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2008-08-23.0000000
e	0.81978762
q (au)	1.027263
a (au)	5.700291
i (deg)	54.981969
Ω (om, deg)	270.342162
ω (w, deg)	207.511518
M (ma, deg)	15.134474

等級

散乱 + 全体線形

$$ M_a = (10.014 + 5.507\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	10.014
n	5.507
gf	0.998
gb	-1.000
k	0.996
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
2020-06-21	2021-10-15	-14.7328	-0.879
2021-10-15	2021-08-27	+8.0581	-2.802
2021-08-27	2022-03-19	-2.3685	+0.975

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	19:02:57.68	-09:07:54.6	HIP 93504	13.43
2026-03-26 12:00	19:03:00.61	-09:06:47.3	HIP 93504	12.75
2026-03-27 00:00	19:03:03.43	-09:05:40.0	HIP 93504	12.16
2026-03-27 12:00	19:03:06.16	-09:04:32.7	HIP 93504	11.68
2026-03-28 00:00	19:03:08.79	-09:03:25.4	HIP 93504	11.32
2026-03-28 12:00	19:03:11.31	-09:02:18.1	HIP 93504	11.07
2026-03-29 00:00	19:03:13.73	-09:01:10.9	HIP 93504	10.95
2026-03-29 12:00	19:03:16.05	-09:00:03.6	HIP 93504	10.95
2026-03-30 00:00	19:03:18.27	-08:58:56.4	HIP 93504	11.07
2026-03-30 12:00	19:03:20.39	-08:57:49.3	HIP 93504	11.31
2026-03-31 00:00	19:03:22.41	-08:56:42.1	HIP 93504	11.64
2026-03-31 12:00	19:03:24.32	-08:55:35.0	HIP 93504	12.07
2026-04-01 00:00	19:03:26.13	-08:54:27.9	HIP 93504	12.57
2026-04-01 12:00	19:03:27.84	-08:53:20.9	HIP 93504	13.14
2026-04-02 00:00	19:03:29.45	-08:52:13.9	HIP 93504	13.77
2026-04-02 12:00	19:03:30.95	-08:51:07.0	HIP 93504	14.44
2026-04-03 00:00	19:03:32.35	-08:50:00.1	HIP 93504	15.15
2026-04-03 12:00	19:03:33.64	-08:48:53.2	HIP 93504	15.89
2026-04-04 00:00	19:03:34.84	-08:47:46.5	HIP 93504	16.65
2026-04-04 12:00	19:03:35.92	-08:46:39.7	HIP 93504	17.44
2026-04-05 00:00	19:03:36.91	-08:45:33.1	HIP 93504	18.24
2026-04-05 12:00	19:03:37.79	-08:44:26.5	HIP 93702	18.60
2026-04-06 00:00	19:03:38.56	-08:43:19.9	HIP 93702	18.12
2026-04-06 12:00	19:03:39.23	-08:42:13.5	HIP 93702	17.73
2026-04-07 00:00	19:03:39.79	-08:41:07.1	HIP 93702	17.43
2026-04-07 12:00	19:03:40.25	-08:40:00.8	HIP 93702	17.23
2026-04-08 00:00	19:03:40.60	-08:38:54.6	HIP 93702	17.11
2026-04-08 12:00	19:03:40.85	-08:37:48.4	HIP 93702	17.10
2026-04-09 00:00	19:03:40.99	-08:36:42.4	HIP 93702	17.18
2026-04-09 12:00	19:03:41.02	-08:35:36.4	HIP 93702	17.36
2026-04-10 00:00	19:03:40.95	-08:34:30.5	HIP 93702	17.63
2026-04-10 12:00	19:03:40.77	-08:33:24.8	HIP 93702	17.99
2026-04-11 00:00	19:03:40.49	-08:32:19.1	HIP 93702	18.43
2026-04-11 12:00	19:03:40.10	-08:31:13.5	HIP 93702	18.94
2026-04-12 00:00	19:03:39.60	-08:30:08.1	HIP 93702	19.53
2026-04-12 12:00	19:03:38.99	-08:29:02.8	HIP 93702	20.18
2026-04-13 00:00	19:03:38.28	-08:27:57.6	HIP 93702	20.89
2026-04-13 12:00	19:03:37.45	-08:26:52.5	HIP 93702	21.66
2026-04-14 00:00	19:03:36.53	-08:25:47.5	HIP 93702	22.47
2026-04-14 12:00	19:03:35.49	-08:24:42.6	HIP 93702	23.33
2026-04-15 00:00	19:03:34.34	-08:23:37.9	HIP 93702	24.22
2026-04-15 12:00	19:03:33.09	-08:22:33.4	HIP 93702	25.16
2026-04-16 00:00	19:03:31.73	-08:21:28.9	HIP 93709	24.87