メタデータ

項目	値
Designation	C/2013 C2 (Tenagra)
Type	C
Perihelion (tp_cal, UTC)	2015-09-02T03:56:21.143040Z
Orbit solution date (soln_date, UTC)	2026-03-07T14:42:52Z
Obs used	550
NEO	-
M1	9.400
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)	2016-07-16.0000000
e	0.43171756
q (au)	9.131701
a (au)	16.068948
i (deg)	21.336708
Ω (om, deg)	247.531370
ω (w, deg)	308.907427
M (ma, deg)	4.863241

等級

散乱 + 全体線形

$$ M_a = (9.703 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	9.703
n	2.000
gf	1.000
gb	-0.509
k	0.800
δ90	8.721

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
2015-12-18	2019-05-05	+33.7951	-32.588
2019-05-05	2025-11-17	-18.1492	+19.881

log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)

ファインディングチャート

天体暦

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-09-20 00:00	20:08:10.76	-00:15:14.4	HIP 99253	11.68
2026-09-20 12:00	20:08:08.40	-00:15:49.5	HIP 99119	11.79
2026-09-21 00:00	20:08:06.09	-00:16:24.6	HIP 99119	11.14
2026-09-21 12:00	20:08:03.84	-00:16:59.7	HIP 99119	10.54
2026-09-22 00:00	20:08:01.65	-00:17:34.8	HIP 99119	9.98
2026-09-22 12:00	20:07:59.52	-00:18:09.8	HIP 99119	9.48
2026-09-23 00:00	20:07:57.44	-00:18:44.8	HIP 99119	9.02
2026-09-23 12:00	20:07:55.43	-00:19:19.8	HIP 99119	8.63
2026-09-24 00:00	20:07:53.47	-00:19:54.7	HIP 99119	8.31
2026-09-24 12:00	20:07:51.57	-00:20:29.6	HIP 99119	8.06
2026-09-25 00:00	20:07:49.74	-00:21:04.4	HIP 99119	7.88
2026-09-25 12:00	20:07:47.96	-00:21:39.1	HIP 99119	7.79
2026-09-26 00:00	20:07:46.24	-00:22:13.9	HIP 99119	7.77
2026-09-26 12:00	20:07:44.58	-00:22:48.5	HIP 99119	7.83
2026-09-27 00:00	20:07:42.98	-00:23:23.1	HIP 99119	7.96
2026-09-27 12:00	20:07:41.44	-00:23:57.7	HIP 99119	8.16
2026-09-28 00:00	20:07:39.97	-00:24:32.1	HIP 99119	8.42
2026-09-28 12:00	20:07:38.55	-00:25:06.5	HIP 99119	8.73
2026-09-29 00:00	20:07:37.19	-00:25:40.9	HIP 99119	9.09
2026-09-29 12:00	20:07:35.90	-00:26:15.1	HIP 99119	9.48
2026-09-30 00:00	20:07:34.66	-00:26:49.3	HIP 99119	9.90
2026-09-30 12:00	20:07:33.49	-00:27:23.4	HIP 99119	10.36
2026-10-01 00:00	20:07:32.37	-00:27:57.4	HIP 99119	10.83
2026-10-01 12:00	20:07:31.32	-00:28:31.3	HIP 99119	11.32
2026-10-02 00:00	20:07:30.33	-00:29:05.1	HIP 99119	11.82
2026-10-02 12:00	20:07:29.41	-00:29:38.9	HIP 99119	12.34
2026-10-03 00:00	20:07:28.54	-00:30:12.5	HIP 99119	12.86
2026-10-03 12:00	20:07:27.74	-00:30:46.0	HIP 99171	13.06
2026-10-04 00:00	20:07:27.00	-00:31:19.4	HIP 99171	12.77
2026-10-04 12:00	20:07:26.32	-00:31:52.7	HIP 99171	12.49
2026-10-05 00:00	20:07:25.70	-00:32:25.9	HIP 99171	12.22
2026-10-05 12:00	20:07:25.15	-00:32:59.0	HIP 99171	11.96
2026-10-06 00:00	20:07:24.66	-00:33:32.0	HIP 99171	11.71
2026-10-06 12:00	20:07:24.23	-00:34:04.8	HIP 99171	11.47
2026-10-07 00:00	20:07:23.87	-00:34:37.5	HIP 99171	11.24
2026-10-07 12:00	20:07:23.57	-00:35:10.1	HIP 99171	11.02
2026-10-08 00:00	20:07:23.33	-00:35:42.5	HIP 99171	10.82
2026-10-08 12:00	20:07:23.16	-00:36:14.8	HIP 99171	10.62
2026-10-09 00:00	20:07:23.05	-00:36:47.0	HIP 99171	10.43
2026-10-09 12:00	20:07:23.00	-00:37:19.0	HIP 99171	10.26
2026-10-10 00:00	20:07:23.02	-00:37:50.9	HIP 99171	10.09
2026-10-10 12:00	20:07:23.10	-00:38:22.6	HIP 99171	9.93
2026-10-11 00:00	20:07:23.24	-00:38:54.2	HIP 99171	9.79