[论文解读] Response to "An empirical examination of WISE/NEOWISE asteroid analysis and results"

E. L. Wright, Amy Mainzer+4 more|CaltechAUTHORS (California Institute of Technology)|Nov 4, 2018

Astro and Planetary Science参考文献 1被引用 9

一句话总结

本文反驳了Myhrvold（2018b）关于WISE/NEOWISE小行星热建模存在根本性缺陷的主张，证明NEOWISE团队的近地小行星热模型（NEATM）在约10%系统不确定度范围内能产生准确的直径和反照率结果。作者指出Myhrvold用于比较数据集的方法存在错误，其报告的红外反照率值过低且不符合物理实际；同时确认WISE测光不确定性已正确表征，且当正确应用时，NEATM仍是大规模小行星调查的有效工具。

ABSTRACT

We show that a number of claims made in Myhrvold (2018) (hereafter M2018b) regarding the WISE data and thermal modeling of asteroids are incorrect. That paper provides thermal fit parameter outputs for only two of the about 150,000 object dataset and does not make a direct comparison to asteroids with diameters measured by other means to assess the quality of that work's thermal model. We are unable to reproduce the results for the two objects for which M2018b published its own thermal fit outputs, including diameter, albedo, beaming, and infrared albedo. In particular, the infrared albedos published in M2018b are unphysically low. [...] While there were some minor issues with consistency between tables due to clerical errors in the WISE/NEOWISE team's various papers and data release in the Planetary Data System, and a software issue that slightly increased diameter uncertainties in some cases, these issues do not substantially change the results and conclusions drawn from the data. We have shown in previous work and with updated analyses presented here that the effective spherical diameters for asteroids published to date are accurate to within the previously quoted minimum systematic 1-sigma uncertainty of about 10 percent when data of appropriate quality and quantity are available. Moreover, we show that the method used by M2018b to compare diameters between various asteroid datasets is incorrect and overestimates their differences. In addition, among other misconceptions in M2018b, we show that the WISE photometric measurement uncertainties are appropriately characterized and used by the WISE data processing pipeline and NEOWISE thermal modeling software. We show that the Near-Earth Asteroid Thermal Model (Harris 1998) employed by the NEOWISE team is a very useful model for analyzing infrared data to derive diameters and albedos when used properly.

研究动机与目标

• 反驳Myhrvold（2018b）声称WISE/NEOWISE小行星热建模存在根本性缺陷的观点。
• 证明NEOWISE团队的近地小行星热模型（NEATM）能产生准确可靠的直径与反照率结果。
• 纠正Myhrvold在比较小行星数据集时的方法论错误，该错误导致结果差异被高估。
• 验证WISE测光测量不确定性已正确报告并可用于热建模。
• 确认尽管存在简化，NEATM仍是大规模小行星调查中实用且有用的模型。

提出的方法

• 作者重新分析了Myhrvold（2018b）发表热拟合结果的两颗特定小行星，使用NEOWISE处理流程重现了结果。
• 将Myhrvold报告的红外反照率与物理上合理的值进行比较，发现其值过低。
• 评估了WISE/NEOWISE数据发布的一致性，识别出少量文书错误和一个影响直径不确定度的软件问题，但结论认为这些不影响核心结果。
• 通过与掩星、雷达及其他任务已知直径的对比，评估NEATM的性能，确认其在约10%系统不确定度范围内准确。
• 重新评估Myhrvold用于比较数据集的方法，证明其数学上存在缺陷，导致差异被夸大。
• 验证了WISE测量不确定性由流程正确报告，仅需对饱和W3波段源进行轻微修正。

实验结果

研究问题

• RQ1 Myhrvold（2018b）报告的两颗小行星的热模型结果是否能通过NEOWISE流程重现？
• RQ2 Myhrvold（2018b）报告的红外反照率是否符合物理实际，还是过低？
• RQ3 Myhrvold用于比较不同数据集中小行星直径的方法是否准确反映了真实差异？
• RQ4 WISE流程报告的测光测量不确定性是否正确表征并可用于热建模？
• RQ5 NEATM是否仍是从WISE/NEOWISE数据推导小行星直径与反照率的有效且有用的模型？

主要发现

• 作者无法重现Myhrvold（2018b）报告的两颗小行星的热拟合结果，包括直径、反照率、热发射因子和红外反照率。
• Myhrvold（2018b）报告的红外反照率值过低，不符合已知物理约束。
• Myhrvold用于比较小行星数据集的方法存在错误，系统性地高估了结果间的差异。
• 当数据质量与数量合适时，NEOWISE团队基于NEATM的结果在约10%系统1-σ不确定度范围内准确。
• WISE测光测量不确定性由流程正确表征，可直接使用，仅需对饱和W3波段源进行轻微修正。
• 尽管存在简化，NEATM仍是大规模小行星调查中实用且有用的模型，尤其在相角小于60°时。