C/2017 T2 (PANSTARRS)

メタデータ

項目
Designation C/2017 T2 (PANSTARRS)
Type C
Perihelion (tp_cal, UTC) 2020-05-04T22:47:55.688640Z
Orbit solution date (soln_date, UTC) 2024-07-30T14:57:25Z
Obs used 6922
NEO -
M1 10.200
K1 4.500
PC -
オスキュレーティング軌道要素
項目
Epoch (epoch_cal, TDB) 2019-12-13.0000000
e 0.99967750
q (au) 1.615095
a (au) 5008.050241
i (deg) 57.231440
Ω (om, deg) 64.378780
ω (w, deg) 92.993316
M (ma, deg) 359.999600

等級

C/2017 T2 (PANSTARRS) · Magnitude (Full range)

散乱 + 全体線形

$$ M_a = (10.827 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目
H0 10.827
n 2.000
gf 1.000
gb -0.653
k 0.800
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
2017-09-15 2019-08-05 +4.1328 -3.262
2019-08-05 2020-01-09 -1.8797 +0.423
2020-01-09 2020-05-04 +5.4565 -2.847
2020-05-05 2020-08-08 +15.7863 -4.493
2020-08-08 2021-10-04 +3.9198 -1.129

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)
2026-06-01 00:00 20:15:29.21 -68:29:41.9 HIP 99850 3.75
2026-06-01 12:00 20:15:19.28 -68:30:56.2 HIP 99850 5.07
2026-06-02 00:00 20:15:09.22 -68:32:10.2 HIP 99850 6.48
2026-06-02 12:00 20:14:59.02 -68:33:23.8 HIP 99850 7.94
2026-06-03 00:00 20:14:48.67 -68:34:37.0 HIP 99850 9.43
2026-06-03 12:00 20:14:38.19 -68:35:49.9 HIP 99850 10.93
2026-06-04 00:00 20:14:27.57 -68:37:02.4 HIP 99850 12.44
2026-06-04 12:00 20:14:16.81 -68:38:14.5 HIP 99850 13.96
2026-06-05 00:00 20:14:05.91 -68:39:26.2 HIP 99481 14.92
2026-06-05 12:00 20:13:54.87 -68:40:37.5 HIP 99481 14.13
2026-06-06 00:00 20:13:43.70 -68:41:48.4 HIP 99481 13.46
2026-06-06 12:00 20:13:32.39 -68:42:58.9 HIP 99481 12.93
2026-06-07 00:00 20:13:20.95 -68:44:09.0 HIP 99481 12.56
2026-06-07 12:00 20:13:09.37 -68:45:18.7 HIP 99481 12.37
2026-06-08 00:00 20:12:57.66 -68:46:27.9 HIP 99481 12.36
2026-06-08 12:00 20:12:45.82 -68:47:36.7 HIP 99481 12.54
2026-06-09 00:00 20:12:33.85 -68:48:45.1 HIP 99481 12.89
2026-06-09 12:00 20:12:21.75 -68:49:53.0 HIP 99481 13.41
2026-06-10 00:00 20:12:09.51 -68:51:00.4 HIP 99481 14.08
2026-06-10 12:00 20:11:57.15 -68:52:07.4 HIP 99481 14.88
2026-06-11 00:00 20:11:44.66 -68:53:13.9 HIP 99481 15.79
2026-06-11 12:00 20:11:32.04 -68:54:19.9 HIP 99237 15.90
2026-06-12 00:00 20:11:19.30 -68:55:25.4 HIP 99237 14.55
2026-06-12 12:00 20:11:06.43 -68:56:30.4 HIP 99237 13.23
2026-06-13 00:00 20:10:53.44 -68:57:35.0 HIP 99237 11.98
2026-06-13 12:00 20:10:40.32 -68:58:39.0 HIP 99237 10.80
2026-06-14 00:00 20:10:27.09 -68:59:42.5 HIP 99237 9.74
2026-06-14 12:00 20:10:13.73 -69:00:45.5 HIP 99237 8.82
2026-06-15 00:00 20:10:00.25 -69:01:47.9 HIP 99237 8.10
2026-06-15 12:00 20:09:46.66 -69:02:49.8 HIP 99237 7.63
2026-06-16 00:00 20:09:32.95 -69:03:51.2 HIP 99237 7.47
2026-06-16 12:00 20:09:19.13 -69:04:52.1 HIP 99237 7.64
2026-06-17 00:00 20:09:05.19 -69:05:52.3 HIP 99237 8.12
2026-06-17 12:00 20:08:51.14 -69:06:52.0 HIP 99237 8.85
2026-06-18 00:00 20:08:36.97 -69:07:51.2 HIP 99237 9.79
2026-06-18 12:00 20:08:22.70 -69:08:49.8 HIP 99237 10.87
2026-06-19 00:00 20:08:08.32 -69:09:47.7 HIP 99237 12.06
2026-06-19 12:00 20:07:53.84 -69:10:45.1 HIP 99237 13.34
2026-06-20 00:00 20:07:39.25 -69:11:42.0 HIP 99237 14.67
2026-06-20 12:00 20:07:24.55 -69:12:38.2 HIP 99237 16.05
2026-06-21 00:00 20:07:09.76 -69:13:33.8 HIP 99237 17.46
2026-06-21 12:00 20:06:54.86 -69:14:28.8 HIP 99237 18.90
2026-06-22 00:00 20:06:39.87 -69:15:23.2 HIP 99104 18.19