How to Search for Possible Bio-signatures on Earth-Like Planets: Beyond a Pale Blue Dot
How to Search for Possible Bio-signatures on Earth-Like Planets: Beyond a Pale Blue Dot
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如何在类地行星上寻找可能的生物特征：超越淡蓝点
DOI：
10.1007/978-981-13-3639-3_29
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发表时间：
2019
期刊：
影响因子：
4.2
通讯作者：
Y. Suto
中科院分区：
文献类型：
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作者：
Y. Suto
从太阳系外看地球，就像卡尔·萨根（Carl Sagan）创造的那样，只是一个淡蓝色的点。为了在可居住区发现的几个类地行星中检测第二个地球上存在生命的可能特征，人们必须开发和建立一种方法来描述行星的特征，而不仅仅是一个淡蓝色的点。我们特别注意圆点颜色随行星自转的周期性变化。由于行星表面的大范围不均匀分布，点的反射光包括不同的颜色分量，对应于覆盖行星表面的陆地，海洋，冰和云。如果我们将点的颜色分解为几个主成分，那么可以依次识别不同表面成分的存在。此外，众所周知，地球上的植被都具有显着的反射特征;反射在波长超过760纳米时会显着增强，这被称为植被的红边。如果人们能在一个淡蓝色的点上识别出相应的颜色特征，它就可以作为生命存在的独特探针。我将描述未来太空任务的方法的可行性，并从天体物理学家的角度考虑天体生物学的方向。
The Earth viewed from outside the Solar system would be identified merely like a pale blue dot, as coined by Carl Sagan. In order to detect possible signatures of the presence of life on a second earth among several terrestrial planets discovered in a habit-able zone, one has to develop and establish a methodology to characterize the planet as something beyond a mere pale blue dot. We pay particular attention to the periodic change of the color of the dot according to the rotation of the planet. Because of the large-scale inhomogeneous distribution of the planetary surface, the reflected light of the dot comprises different color components corresponding to land, ocean, ice, and cloud that cover the surface of the planet. If we decompose the color of the dot into several principle components, in turn, one can identify the presence of the different surface components. Furthermore, the vegetation on the earth is known to share a remarkable reflection signature; the reflection becomes significantly enhanced at wave-lengths longer than 760nm, which is known as a red-edge of the vegetation. If one can identify the corresponding color signature in a pale blue dot, it can be used as a unique probe of the presence of life. I will describe the feasibility of the methodology for future space missions, and consider the direction towards astrobiology from an astrophysicist's point of view.
DOI：
10.1088/0004-637x/720/2/1333
发表时间：
2010-04
期刊：
The Astrophysical Journal
影响因子：
--
作者：
H. Kawahara;Y. Fujii
通讯作者：
H. Kawahara;Y. Fujii