High stellar FUV/NUV ratio and oxygen contents in the atmospheres of potentially habitable planets

Recent observations of several planet-hosting M dwarfs show that most have FUV/NUV flux ratios 1000 times greater than that of the Sun. Here we show that the atmospheric oxygen contents (O2 and O3) of potentially habitable planets in this type of UV environment could be 2–3 orders of magnitude great...

Full description

Saved in:
Bibliographic Details
Published in:Earth and planetary science letters 2014-01, Vol.385, p.22-27
Main Authors: Tian, Feng, France, Kevin, Linsky, Jeffrey L., Mauas, Pablo J.D., Vieytes, Mariela C.
Format: Article
Language:English
Subjects:
atmosphere photochemistry
Atmospherics
biosignature
Carbon dioxide
Dwarf stars
exoplanet
Extrasolar planets
Flux
habitable planet
Oxygen content
Photolysis
Planet detection
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Recent observations of several planet-hosting M dwarfs show that most have FUV/NUV flux ratios 1000 times greater than that of the Sun. Here we show that the atmospheric oxygen contents (O2 and O3) of potentially habitable planets in this type of UV environment could be 2–3 orders of magnitude greater than those of their counterparts around Sun-like stars as a result of decreased photolysis of O3, H2O2, and HO2. Thus detectable levels of atmospheric oxygen, in combination with the existence of H2O and CO2, may not be the most promising biosignatures on planets around stars with high FUV/NUV ratios such as the observed M dwarfs. •The observed UV spectrum of some planet-hosting M dwarfs leads to different photochemistry.•It is easier to accumulate atmospheric oxygen on lifeless planets around such stars.•The accumulated oxygen could be detected and thus could form a “false positive” biosignature.
ISSN:0012-821X
1385-013X
DOI:10.1016/j.epsl.2013.10.024