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)
2026-07-29 00:00	20:16:29.98	+00:36:03.5	HIP 100121	31.96
2026-07-29 12:00	20:16:23.91	+00:35:46.8	HIP 100121	33.49
2026-07-30 00:00	20:16:17.85	+00:35:29.7	HIP 100121	35.03
2026-07-30 12:00	20:16:11.79	+00:35:12.3	HIP 99948	36.53
2026-07-31 00:00	20:16:05.73	+00:34:54.6	HIP 99948	37.20
2026-07-31 12:00	20:15:59.69	+00:34:36.6	HIP 99748	35.98
2026-08-01 00:00	20:15:53.65	+00:34:18.2	HIP 99748	34.73
2026-08-01 12:00	20:15:47.62	+00:33:59.5	HIP 99748	33.49
2026-08-02 00:00	20:15:41.60	+00:33:40.5	HIP 99748	32.28
2026-08-02 12:00	20:15:35.59	+00:33:21.2	HIP 99748	31.10
2026-08-03 00:00	20:15:29.59	+00:33:01.5	HIP 99748	29.94
2026-08-03 12:00	20:15:23.61	+00:32:41.6	HIP 99748	28.82
2026-08-04 00:00	20:15:17.63	+00:32:21.3	HIP 99748	27.73
2026-08-04 12:00	20:15:11.66	+00:32:00.7	HIP 99748	26.69
2026-08-05 00:00	20:15:05.71	+00:31:39.8	HIP 99748	25.69
2026-08-05 12:00	20:14:59.77	+00:31:18.6	HIP 99748	24.74
2026-08-06 00:00	20:14:53.85	+00:30:57.1	HIP 99748	23.84
2026-08-06 12:00	20:14:47.94	+00:30:35.3	HIP 99748	23.01
2026-08-07 00:00	20:14:42.05	+00:30:13.2	HIP 99748	22.25
2026-08-07 12:00	20:14:36.17	+00:29:50.8	HIP 99748	21.57
2026-08-08 00:00	20:14:30.31	+00:29:28.1	HIP 99748	20.96
2026-08-08 12:00	20:14:24.46	+00:29:05.1	HIP 99748	20.45
2026-08-09 00:00	20:14:18.64	+00:28:41.9	HIP 99748	20.04
2026-08-09 12:00	20:14:12.83	+00:28:18.3	HIP 99748	19.72
2026-08-10 00:00	20:14:07.04	+00:27:54.5	HIP 99748	19.51
2026-08-10 12:00	20:14:01.27	+00:27:30.3	HIP 99748	19.41
2026-08-11 00:00	20:13:55.52	+00:27:05.9	HIP 99748	19.42
2026-08-11 12:00	20:13:49.80	+00:26:41.3	HIP 99748	19.54
2026-08-12 00:00	20:13:44.09	+00:26:16.3	HIP 99748	19.76
2026-08-12 12:00	20:13:38.41	+00:25:51.1	HIP 99748	20.08
2026-08-13 00:00	20:13:32.75	+00:25:25.7	HIP 99748	20.50
2026-08-13 12:00	20:13:27.12	+00:25:00.0	HIP 99748	21.01
2026-08-14 00:00	20:13:21.50	+00:24:33.9	HIP 99748	21.60
2026-08-14 12:00	20:13:15.92	+00:24:07.7	HIP 99748	22.26
2026-08-15 00:00	20:13:10.36	+00:23:41.2	HIP 99748	22.99
2026-08-15 12:00	20:13:04.82	+00:23:14.5	HIP 99748	23.78
2026-08-16 00:00	20:12:59.32	+00:22:47.5	HIP 99748	24.62
2026-08-16 12:00	20:12:53.84	+00:22:20.3	HIP 99748	25.50
2026-08-17 00:00	20:12:48.39	+00:21:52.8	HIP 99748	26.43
2026-08-17 12:00	20:12:42.96	+00:21:25.2	HIP 99459	26.10
2026-08-18 00:00	20:12:37.57	+00:20:57.3	HIP 99459	25.14
2026-08-18 12:00	20:12:32.21	+00:20:29.1	HIP 99459	24.25
2026-08-19 00:00	20:12:26.87	+00:20:00.8	HIP 99459	23.41