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arXiv · 1410.6488

The Near-Ultraviolet Luminosity Function of Young, Early M-Type Dwarf Stars

Megan Ansdell·Eric Gaidos·Andrew W. Mann·Sebastien Lepine·David James·Andrea Buccino·Christoph Baranec·Nicholas M. Law·Reed Riddle·Pablo Mauas·Romina Petrucci
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Abstract

Planets orbiting within the close-in habitable zones of M dwarf stars will be exposed to elevated high-energy radiation driven by strong magneto-hydrodynamic dynamos during stellar youth. Near-ultraviolet (NUV) irradiation can erode and alter the chemistry of planetary atmospheres, and a quantitative description of the evolution of NUV emission from M dwarfs is needed when modeling these effects. We investigated the NUV luminosity evolution of early M-type dwarfs by cross-correlating the Lepine & Gaidos (2011) catalog of bright M dwarfs with the GALEX catalog of NUV (1771-2831A) sources. Of the 4805 sources with GALEX counterparts, 797 have NUV emission significantly (> 2.5 sigma) in excess of an empirical basal level. We inspected these candidate active stars using visible-wavelength spectra, high-resolution adaptive optics imaging, time-series photometry, and literature searches to identify cases where the elevated NUV emission is due to unresolved background sources or stellar companions; we estimated the overall occurrence of these "false positives" as ~16%. We constructed a NUV luminosity function that accounted for false positives, detection biases of the source catalogs, and GALEX upper limits. We found the NUV luminosity function to be inconsistent with predictions from a constant star-formation rate and simplified age-activity relation defined by a two-parameter power law.

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Megan Ansdell, Eric Gaidos, Andrew W. Mann, Sebastien Lepine, David James, Andrea Buccino, Christoph Baranec, Nicholas M. Law, Reed Riddle, Pablo Mauas, Romina Petrucci. 2014-10-23. The Near-Ultraviolet Luminosity Function of Young, Early M-Type Dwarf Stars. https://doi.org/10.1088/0004-637x/798/1/41

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