C/2015 X7 (ATLAS)

メタデータ

項目
Designation C/2015 X7 (ATLAS)
Type C
Perihelion (tp_cal, UTC) 2016-07-30T05:59:33.682560Z
Orbit solution date (soln_date, UTC) 2021-04-15T23:33:20Z
Obs used 620
NEO -
M1 11.600
K1 6.000
PC -
オスキュレーティング軌道要素
項目
Epoch (epoch_cal, TDB) 2016-09-22.0000000
e 1.00189036
q (au) 3.684550
a (au) -1949.127032
i (deg) 57.578925
Ω (om, deg) 139.884070
ω (w, deg) 348.488537
M (ma, deg) 0.000616

等級

C/2015 X7 (ATLAS) · Magnitude (Full range)

散乱 + 全体線形

$$ M_a = (11.078 + 2.092\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目
H0 11.078
n 2.092
gf 1.000
gb -0.998
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
2015-01-28 2016-05-01 -0.2726 -0.309
2016-11-02 2017-06-16 -0.5340 +0.555

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)
2026-05-12 00:00 18:31:40.21 +24:34:39.7 HIP 90919 16.53
2026-05-12 12:00 18:31:36.76 +24:35:14.4 HIP 90919 17.07
2026-05-13 00:00 18:31:33.26 +24:35:48.7 HIP 90919 17.65
2026-05-13 12:00 18:31:29.73 +24:36:22.6 HIP 90919 18.28
2026-05-14 00:00 18:31:26.17 +24:36:56.2 HIP 90919 18.95
2026-05-14 12:00 18:31:22.57 +24:37:29.4 HIP 90919 19.65
2026-05-15 00:00 18:31:18.93 +24:38:02.2 HIP 90919 20.39
2026-05-15 12:00 18:31:15.25 +24:38:34.7 HIP 90919 21.15
2026-05-16 00:00 18:31:11.55 +24:39:06.7 HIP 90919 21.94
2026-05-16 12:00 18:31:07.80 +24:39:38.4 HIP 90919 22.76
2026-05-17 00:00 18:31:04.03 +24:40:09.6 HIP 90919 23.59
2026-05-17 12:00 18:31:00.22 +24:40:40.5 HIP 90919 24.45
2026-05-18 00:00 18:30:56.37 +24:41:11.0 HIP 90919 25.33
2026-05-18 12:00 18:30:52.49 +24:41:41.1 HIP 90919 26.22
2026-05-19 00:00 18:30:48.58 +24:42:10.7 HIP 90919 27.13
2026-05-19 12:00 18:30:44.64 +24:42:40.0 HIP 90770 27.72
2026-05-20 00:00 18:30:40.66 +24:43:08.8 HIP 90770 27.45
2026-05-20 12:00 18:30:36.66 +24:43:37.3 HIP 90770 27.22
2026-05-21 00:00 18:30:32.62 +24:44:05.3 HIP 90770 27.04
2026-05-21 12:00 18:30:28.55 +24:44:32.9 HIP 90770 26.91
2026-05-22 00:00 18:30:24.45 +24:45:00.1 HIP 90699 26.50
2026-05-22 12:00 18:30:20.32 +24:45:26.9 HIP 90699 26.02
2026-05-23 00:00 18:30:16.16 +24:45:53.2 HIP 90699 25.57
2026-05-23 12:00 18:30:11.97 +24:46:19.1 HIP 90699 25.17
2026-05-24 00:00 18:30:07.75 +24:46:44.6 HIP 90699 24.81
2026-05-24 12:00 18:30:03.50 +24:47:09.6 HIP 90699 24.50
2026-05-25 00:00 18:29:59.23 +24:47:34.2 HIP 90699 24.24
2026-05-25 12:00 18:29:54.93 +24:47:58.4 HIP 90699 24.03
2026-05-26 00:00 18:29:50.60 +24:48:22.1 HIP 90699 23.87
2026-05-26 12:00 18:29:46.24 +24:48:45.4 HIP 90699 23.77
2026-05-27 00:00 18:29:41.86 +24:49:08.3 HIP 90699 23.73
2026-05-27 12:00 18:29:37.45 +24:49:30.7 HIP 90699 23.74
2026-05-28 00:00 18:29:33.01 +24:49:52.6 HIP 90699 23.81
2026-05-28 12:00 18:29:28.55 +24:50:14.2 HIP 90699 23.94
2026-05-29 00:00 18:29:24.06 +24:50:35.2 HIP 90483 23.94
2026-05-29 12:00 18:29:19.55 +24:50:55.8 HIP 90483 23.12
2026-05-30 00:00 18:29:15.01 +24:51:16.0 HIP 90483 22.32
2026-05-30 12:00 18:29:10.45 +24:51:35.7 HIP 90483 21.53
2026-05-31 00:00 18:29:05.87 +24:51:54.9 HIP 90483 20.76
2026-05-31 12:00 18:29:01.26 +24:52:13.7 HIP 90483 20.01
2026-06-01 00:00 18:28:56.63 +24:52:32.0 HIP 90483 19.29
2026-06-01 12:00 18:28:51.98 +24:52:49.9 HIP 90483 18.59
2026-06-02 00:00 18:28:47.31 +24:53:07.3 HIP 90483 17.93