J. Sebastian Pineda, Michael Bottom, John A. Johnson
We construct high signal-to-noise "template" spectra by co-adding hundreds of spectra of nearby dwarfs spanning K7 to M4, taken with Keck/HIRES as part of the California Planet Search. We identify several spectral regions in the visible (370 - 800 nm) that are sensitive to the stellar luminosity and metallicity. We use these regions to develop a spectral calibration method to measure the mass, metallicity, and distance of low-mass stars, without the requirement of geometric parallaxes. Testing our method on a sample of nearby M dwarfs we show that we can reproduce stellar masses to about 8 - 10%, metallicity to $\sim 0.15$ dex and distance to 11%. We were able to make use of HIRES spectra obtained as part of the radial velocity monitoring of the star KOI-314 to derive a new mass estimate of $0.57 \pm 0.05$ $M_{\odot}$, a radius of $0.54\pm0.05$ $R_{\odot}$, a metallicity, [Fe/H], of $-0.28 \pm 0.10$ and a distance of $66.5\pm7.3$ pc. Using HARPS archival data and combining our spectral method with constraints from transit observations, we are also able to derive the stellar properties of GJ$\,$3470, a transiting planet hosting M dwarf. We estimate a mass of $0.53 \pm 0.05$ $M_{\odot}$, a radius of $0.50\pm0.05$ $R_{\odot}$, a metallicity, [Fe/H], of $0.12 \pm 0.12$ and a distance of $29.9\pm_{3.4}^{3.7}$ pc.
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http://arxiv.org/abs/1302.6231
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