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Richey-Yowell_2019_ApJ_872_17.pdf
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Final Published version
Author
Richey-Yowell, TylerShkolnik, Evgenya L.
Schneider, Adam C.

Osby, Ella
Barman, Travis
Meadows, Victoria S.
Affiliation
Univ Arizona, Lunar & Planetary LabIssue Date
2019-02-10
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IOP PUBLISHING LTDCitation
Tyler Richey-Yowell et al 2019 ApJ 872 17Journal
ASTROPHYSICAL JOURNALRights
© 2019. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Knowing the high-energy radiation environment of a star over a planet's formation and evolutionary period is critical in determining if that planet is potentially habitable and if any biosignatures could be detected, as UV radiation can severely change or destroy a planet's atmosphere. Current efforts for finding a potentially habitable planet are focused on M stars, yet K stars may offer more habitable conditions due to decreased stellar activity and more distant and wider habitable zones (HZs). While M star activity evolution has been observed photometrically and spectroscopically, there has been no dedicated investigation of K star UV evolution. We present the first comprehensive study of the near-UV, far-UV, and X-ray evolution of K stars. We used members of young moving groups and clusters ranging in age from 10 to 625 Myr combined with field stars and their archived GALEX UV and ROSAT X-ray data to determine how the UV and X-ray radiation evolve. We find that the UV and X-ray flux incident on an HZ planet is 5-50 times lower than that of HZ planets around early-M stars and 50-1000 times lower than those around late-M stars, due to both an intrinsic decrease in K dwarf stellar activity occurring earlier than for M dwarfs and the more distant location of the K dwarf HZ.ISSN
1538-4357Version
Final published versionSponsors
NASA Habitable Worlds [NNX16AB62G]; California Institute of Technology under NASA [NAS5-98034]; National Aeronautics and Space Administration; National Science FoundationAdditional Links
http://stacks.iop.org/0004-637X/872/i=1/a=17?key=crossref.784dbcc4d4bb77707f44508f7d86a42cae974a485f413a2113503eed53cd6c53
10.3847/1538-4357/aafa74