论文标题
金星云中膦的重新分析
Re-analysis of Phosphine in Venus' Clouds
论文作者
论文摘要
我们首先回应了Villanueeva等人提出的两点。我们表明，PH3的JCMT发现谱不能重新归入SO2，因为该线宽度比SO2特征所观察到的要大，并且所需的丰度将是一个极端的离群值。 JCMT频谱也与我们的简单模型，恒定的pH3充分性（具有高度）一致，没有线轮廓的差异（在数据限制内）；与完整的光化学模型的对帐是未来工作的主题。第2节介绍了重新处理的ALMA数据的初始结果。 Villanueva等。注意到带通校准的问题。他们已经在ALMA数据的部分重新处理的子集上工作，因此我们注意到他们的结论以及Greaves等人的结论现在被取代。总结：我们以阿尔玛（〜5σ置信度）在金星的大气中恢复了PH3。局部丰度似乎达到约5-10亿（PPB）的峰值，并提出了空间变化的建议。先进的数据产品表明，行星平均的PH3丰度〜1-4 ppb，低于早期的ALMA处理（表明7+ PPB）。如果存在刻板时间变化，则ALMA数据可与JCMT检测（〜20 ppb）对帐；正在进行JCMT数据的更高级处理以检查方法。独立的pH3测量表明可能的高度依赖性（在60 km处〜5 ppb以下，在50+ km处高达〜100 ppb；请参见第2节：结论。）。鉴于ALMA和JCMT都处于天文台功能的极限，因此应获得新的光谱。 ALMA数据不再受校准的限制，但是光谱波纹仍然存在，这可能是由于金星与主要光束相关的大小和亮度所致。此外，存在空间波纹，可能会降低实际狭窄光谱特征的重要性。
We first respond to two points raised by Villanueva et al. We show the JCMT discovery spectrum of PH3 can not be re-attributed to SO2, as the line width is larger than observed for SO2 features, and the required abundance would be an extreme outlier. The JCMT spectrum is also consistent with our simple model, constant PH3-abundance with altitude, with no discrepancy in line profile (within data limits); reconciliation with a full photochemical model is the subject of future work. Section 2 presents initial results from re-processed ALMA data. Villanueva et al. noted an issue with bandpass calibration. They have worked on a partially re-processed subset of the ALMA data, so we note where their conclusions, and those of Greaves et al., are now superseded. To summarise: we recover PH3 in Venus' atmosphere with ALMA (~5σ confidence). Localised abundance appears to peak at ~5-10 parts-per-billion (ppb), with suggestions of spatial variation. Advanced data-products suggest a planet-averaged PH3 abundance ~1-4 ppb, lower than from the earlier ALMA processing (which indicated 7+ ppb). The ALMA data are reconcilable with the JCMT detection (~20 ppb) if there is order-of-magnitude temporal variation; more advanced processing of the JCMT data is underway to check methods. Independent PH3 measurements suggest possible altitude dependence (under ~5 ppb at 60+ km, up to ~100 ppb at 50+ km; see Section 2: Conclusions.). Given that both ALMA and JCMT were working at the limit of observatory capabilities, new spectra should be obtained. The ALMA data in-hand are no longer limited by calibration, but spectral ripples still exist, probably due to size and brightness of Venus in relation to the primary beam. Further, spatial ripples are present, potentially reducing significance of real narrow spectral features.
