Exoplanet discovery has made remarkable progress, with the first rocky planets having been detected in the central star’s liquid water habitable zone. The remote sensing techniques used to characterize such planets for potential habitability and life rely solely on our understanding of life on Earth. The vegetation red edge from terrestrial land plants is often used as a direct signature of life, but it occupies only a small niche in the environmental parameter space that binds life on present-day Earth and has been widespread for only about 460 My. To more fully exploit the diversity of the one example of life known, we measured the spectral characteristics of 137 microorganisms containing a range of pigments, including ones isolated from Earth’s most extreme environments. Our database covers the visible and near-infrared to the short-wavelength infrared (0.35–2.5 μm) portions of the electromagnetic spectrum and is made freely available on this website. Our results show how the reflectance properties are dominated by the absorption of light by pigments in the visible portion and by strong absorptions by the cellular water of hydration in the infrared (up to 2.5 μm) portion of the spectrum. Our spectral library provides a broader and more realistic guide based on Earth life for the search for surface features of extraterrestrial life. The library, when used as inputs for modeling disk-integrated spectra of exoplanets, in preparation for the next generation of space- and ground-based instruments, will increase the chances of detecting life.
Citing this biosignature catalogue: Hegde S., Paulino-Lima I. G., Kent R., Kaltenegger L., & Rothschild L., Surface biosignatures of exo-Earths: Remote detection of extraterrestrial life, Proceedings of the National Academy of Sciences of the United States of America (PNAS). March 2015, 112 (13) 3886-3891.
Online link to the article: Surface biosignatures of exo-Earths: Remote detection of extraterrestrial life.
Contact Information: Dr Siddharth Hegde; Email: sidworld at gmail dot com, shegde at astro.cornell.edu
Sample name | Description-files | Spectral-Plots | Data-files |
---|---|---|---|
Agrococcus sp._KM349956 | |||
Alphaproteobacteria_KM349946 | |||
Amphidinium carterae | |||
Anabaena sp. str. PCC 7120 | |||
Anabaena sp. str. PCC 7120 with green fluorescent protein | |||
Arthrobacter sp._KM349883 | |||
Arthrobacter sp._KM349893 | |||
Arthrobacter sp._KM349898 | |||
Arthrobacter sp._KM349916 | |||
Arthrobacter sp._KM349918 | |||
Arthrobacter sp._KM349919 | |||
Arthrobacter sp._KM349921 | |||
Arthrobacter sp._KM349924 | |||
Arthrobacter sp._KM349938 | |||
Arthrobacter sp._KM349939 | |||
Arthrobacter sp._KM349943 | |||
Arthrobacter sp._KM349958 | |||
Azospirillum sp._KM349895 | |||
Bacillales_KM349901 | |||
Bacillales_KM349923 | |||
Bacillales_KM349934 | |||
Bacillales_KM349937 | |||
Bacillales_KM349940 | |||
Bacillus sp._KM349861 | |||
Bacillus sp._KM349863 | |||
Bacillus sp._KM349864 | |||
Bacillus sp._KM349865 | |||
Bacillus sp._KM349866 | |||
Bacillus sp._KM349867 | |||
Bacillus sp._KM349868 | |||
Bacillus sp._KM349869 | |||
Bacillus sp._KM349870 | |||
Bacillus sp._KM349871 | |||
Bacillus sp._KM349872 | |||
Bacillus sp._KM349873 | |||
Bacillus sp._KM349874 | |||
Bacillus sp._KM349875 | |||
Bacillus sp._KM349876 | |||
Bacillus sp._KM349877 | |||
Bacillus sp._KM349878 | |||
Bacillus sp._KM349887 | |||
Bacillus sp._KM349899 | |||
Bacillus sp._KM349902 | |||
Bacillus sp._KM349906 | |||
Bacillus sp._KM349911 | |||
Bacillus sp._KM349913 | |||
Bacillus sp._KM349915 | |||
Bacillus sp._KM349927 | |||
Bacillus sp._KM349928 | |||
Bacillus sp._KM349929 | |||
Bacillus sp._KM349930 | |||
Bacillus sp._KM349931 | |||
Bacillus sp._KM349941 | |||
Bacillus subtilis 168 plus chromogenic protein | |||
bacterium | |||
bacterium | |||
Basidiomycota sp._KM349879 | |||
Betaproteobacteria_KM349948 | |||
Calothrix parietina | |||
Cellulomonas sp._KM349959 | |||
Chaetoceros gracilis | |||
Chaetoceros sp. | |||
Chlorella protothecoides | |||
Chlorellaceae_KM349944 | |||
Chroococcidiopsis sp. | |||
Cryptomonas ovata | |||
Cyanidium caldarium | |||
Cyanophora biloba | |||
Cylindrotheca fusiformis | |||
Cytophagaceae_KM349914 | |||
Deinococcus radiodurans | |||
Dermocarpa violacea | |||
Dunaliella salina | |||
Dunaliella sp. | |||
Ectocarpus siliculosus | |||
Ectothiorhodospira sp. str. BSL-9 | |||
Escherichia coli | |||
Euglena gracilis var. saccharophila | |||
Firmicutes_KM349903 | |||
Flavobacterium sp._KM349957 | |||
Geodermatophilaceae_KM349892 | |||
Geodermatophilus sp._KM349882 | |||
Gloeocapsa sp. | |||
Haematococcus droebakensis | |||
Halorubrum chaoviator str. Halo-G*T_AM048786 | |||
Hydrogenophaga sp._KM349947 | |||
Hydrogenophaga sp._KM349962 | |||
Hymenobacter sp._KM349884 | |||
Isochrysis galbana | |||
Kocuria sp._KM349888 | |||
Kocuria sp._KM349891 | |||
Kocuria sp._KM349896 | |||
Kocuria sp._KM349900 | |||
Kocuria sp._KM349907 | |||
Kocuria sp._KM349908 | |||
Kocuria sp._KM349909 | |||
Kocuria sp._KM349917 | |||
Kocuria sp._KM349920 | |||
Kocuria sp._KM349926 | |||
Kocuria sp._KM349935 | |||
Kocuria sp._KM349964 | |||
Lyngbya purpurem | |||
Methylobacterium sp._KM349880 | |||
Methylobacterium sp._KM349881 | |||
Methylobacterium sp._KM349885 | |||
Microbacterium sp._KM349942 | |||
Micrococcaceae_KM349922 | |||
Nannochloropsis oculata | |||
Nocardioides sp._KM349960 | |||
Oocystis minuta | |||
Paracoccus sp._KM349912 | |||
Pedobacter sp._KM349886 | |||
Phormidium inundatum | |||
Phormidium sp. | |||
Planococcaceae_KM349897 | |||
Planococcaceae_KM349910 | |||
Planococcaceae_KM349932 | |||
Planococcaceae_KM349933 | |||
Planococcaceae_KM349955 | |||
Planomicrobium sp._KM349904 | |||
Pontibacter sp._KM349890 | |||
Pontibacter sp._KM349894 | |||
Porphyridium purpureum | |||
Prorocentrum micans | |||
Ramlibacter sp._KM349961 | |||
Rhodococcus sp._KM349949 | |||
Rhodosorus marinus | |||
Spirulina platensis | |||
Sporidiobolales_KM349951 | |||
Sporidiobolales_KM349953 | |||
Sporidiobolales_KM349954 | |||
Sporosarcina sp._KM349905 | |||
Streptomyces sp._KM349862 | |||
Streptomyces sp._KM349965 | |||
Synechococcus leopoliensis | |||
Synechococcus sp. | |||
Synechococcus sp. with reduced phycocyanin |