As infrared telescopes are finding evidence of methane in hot exoplanet atmospheres, it is becoming increasingly important to have accurate high-temperature methane absorption models. To evaluate and update several spectroscopic databases (HITRAN2016, HITEMP, ExoMol), we collected laboratory spectra of the methane icosad (6770-7570 cm^-1) using a 200 MHz (0.0067 cm^-1) dual frequency comb spectrometer. The pure methane data span 18 to 300 Torr and 296 to 1000 K. We found good agreement with the HITRAN2016 model spectrum at room temperature, and substantial mismatch between our spectra and all absorption models at elevated temperature. We present several updates to HITRAN2016 to improve agreement with the measured high-temperature spectra. Specifically, we assign 4283 lower-state energies which had previously been given a default value in HITRAN2016 ($E_{HIT}^{″}$= 999 cm^-1), update existing lower-state energies for 92 features, and add 293 new high-temperature features in order to improve HITRAN2016 above 300 K. Additionally, we update the band-wide line positions by $\sim$0.001 cm^-1, the self-widths by +7%, and we estimate band-averaged temperature-dependence exponents for self-width (0.85) and self-shift (0.58). These measurements are an important step towards merging empirical and theoretical high-temperature methane databases, with the goal of enabling better understanding of exoplanet atmospheres.

随着红外望远镜在热的系外行星大气中发现甲烷的证据，拥有准确的高温甲烷吸收模型变得越来越重要。评估和更新多个光谱数据库（HITRAN2016，HITEMP，ExoMol），我们所收集的甲烷icosad的实验室光谱（6770-7570厘米^-1使用200兆赫）（0.0067厘米^-1) 双频梳光谱仪。纯甲烷数据的范围为 18 至 300 Torr 和 296 至 1000 K。我们发现室温下与 HITRAN2016 模型光谱非常吻合，并且我们的光谱与高温下的所有吸收模型之间存在严重不匹配。我们对 HITRAN2016 进行了一些更新，以提高与测量的高温光谱的一致性。具体来说，我们分配了 4283 个低态能量，这些能量之前在 HITRAN2016 中被赋予了默认值（${乙}_{H\mathrm{一世}吨}^{”}$= 999 cm ^-1 )，更新 92 个特征的现有低态能量，并添加 293 个新的高温特征，以将 HITRAN2016 提高到 300 K 以上。此外，我们更新了带宽线位置$～$0.001 cm ^-1，自宽为 +7%，我们估计自宽 (0.85) 和自位移 (0.58) 的带平均温度依赖性指数。这些测量是合并经验和理论高温甲烷数据库的重要一步，目的是更好地了解系外行星大气。