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dc.contributor.authorMuirhead, Philipen_US
dc.coverage.spatialReykjavik, Icelanden_US
dc.date.accessioned2020-04-23T14:55:19Z
dc.date.available2020-04-23T14:55:19Z
dc.date.issued2019-08-23
dc.identifierhttps://sites.northwestern.edu/iceland2019/
dc.identifier.citationPhilip Muirhead. 2019. "Are Exoplanets Orbiting M Dwarfs Extreme?."
dc.identifier.urihttps://hdl.handle.net/2144/40308
dc.descriptionI gave an invited talk at Extreme Solar Systems IV in REYKJAVIK, ICELAND. However, please note that all talks were officially "invited" according to the organizers.en_US
dc.description.abstractM dwarf stars have long spin-down timescales, long activity lifetimes and persistent magnetic activity, all of which have implications for the potential habitability of orbiting planets. I will present results from several research programs investigating M dwarf rotation, activity and evolution. I will discuss a new technique to measure chemical-kinematic ages of main-sequence M dwarf stars. We applied that technique to a variety of nearby M dwarfs, both planet hosts and non-planet hosts, and rapid (young) and slow (old) rotators. We find that relatively slow rotators (P 100 days) do not appear to be α enriched, indicating that they are not over 10 Gyrs old. Second, for the rapid rotators, we see clear evidence of Zeeman enhancement of Y-band Ti I lines as a function of Rossby number. While other activity indicators, such as H-α and X-ray emission, appear to saturate with low Rossby number, Zeeman enhancement does not, indicating that the saturation mechanism is confined to the chromosphere and corona. Finally, I will present new results on the M dwarf radius problem. Using spectral synthesis methods, we find that large magnetic star spot fractions are primarily responsible for observed discrepancies between model and measured stellar radii in fully convective M dwarf stars. As most M dwarfs appear discrepant, our results suggest the vast majority of M dwarfs have large spot fractions and correspondingly high localization of magnetic fields.en_US
dc.titleAre exoplanets orbiting m dwarfs extreme?en_US
dc.typePresentationen_US
dc.description.versionPublished versionen_US
pubs.elements-sourcemanual-entryen_US
pubs.notesAbstract is available on ADS: https://ui.adsabs.harvard.edu/abs/2019ESS.....450201M/abstracten_US
pubs.notesEmbargo: Not knownen_US
pubs.organisational-groupBoston Universityen_US
pubs.organisational-groupBoston University, College of Arts & Sciencesen_US
pubs.organisational-groupBoston University, College of Arts & Sciences, Department of Astronomyen_US
dc.identifier.orcid0000-0002-0638-8822 (Muirhead, Philip)
dc.identifier.mycv514776


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