Collaborative Research: Formation, Stability, and Detection of Amorphous Ferric Sulfate Salts on Mars

对行星表面组成的精确测定对于理解形成太阳系的过程至关重要。在地球之外，矿物学是通过望远镜、轨道卫星以及火星上的着陆器和漫游者的观测来研究的。有精确的测量“库”来显示不同的矿物如何反射不同颜色的光是至关重要的。没有对比样品，就无法进行匹配。地球上常见的物质已经得到了很好的研究。然而，火星表面还没有很好地描述在陆地研究中常见的物质。富含水（“水合”）的非晶体材料（“无定形”）在火星上无处不在，但在地球上还没有得到很好的研究。研究人员建议为可能在火星上发现的水合无定形物质建立一个反射率测量库。他们将研究光反射率如何随温度变化，以及酸的风化如何改变样品的反射率。他们将包括本科生参与研究，并期望至少有六篇本科生论文或独立研究项目将从这个项目中产生。作为联合pi Dyar是Mount Holyoke（一所女子学院）和五所学院天文学联合会的教员，预计许多学生参与者将是女性。工作的目的是确定无定形硫酸铁盐和盐混合物的稳定性和转化产物，测量可能的风化层材料的光谱a)涂覆这些材料和b)与这些材料混合；并利用实验室光谱在火星侦察轨道器紧凑型火星侦察成像光谱仪（CRISM）和火星全球勘测者热发射光谱仪（TES）数据中搜索和绘制无定形硫酸铁、无定形混合盐和无定形盐涂层的光谱特征。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

An accurate determination of the surface composition of planets is essential for understanding the processes that have shaped our Solar System. Beyond Earth, mineralogy is studied using observations from telescopes, orbiting satellites, and in the case of Mars, landers and rovers. It is essential to have accurate "libraries" of measurements showing how different minerals reflect light of different colors. Without comparison samples, a match cannot be made. Materials that are common on Earth have been well studied. However, the surface of Mars is not yet well described in terms of materials that are common in terrestrial studies. Non-crystalline materials ("amorphous") that are rich in water ("hydrated") are ubiquitous on Mars yet are not well studied on Earth. The investigators propose to create a library of reflectance measurements for hydrated amorphous materials that are likely to be found on Mars. They will study how the light reflectance varies with temperature, and how weathering by acids changes the reflectance of a sample. They will include undergraduate students in the research and expect that at least six undergraduate thesis or independent study projects will emerge from this project. As co-PI Dyar is a faculty member at Mount Holyoke (a women's college) and the Five Colleges Astronomy Consortium, many of the student participants are expected to be women.The objectives of the work are to determine the stability and transformation products of amorphous ferric sulfate salts and salt mixtures, measure the spectra of possible regolith materials a) coated with these materials and b) mixed with these materials; and to use the laboratory spectra to search for and map spectral features of amorphouse ferric sulfates, amorphous mixed salts, and amorphous salt coatings in Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and Mars Global Surveyor Thermal Emission Spectrometer (TES) data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.