We present the effective temperatures (T-eff), metallicities, and colours in Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer filters, of a sample of 3834 late-K and early-M dwarfs selected from the SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectroscopic survey ASPCAP (APOGEE Stellar Parameters and Chemical Abundances Pipeline) catalogue. We confirm that ASPCAP T-eff values between 3550 < T-eff < 4200 K are accurate to similar to 100 K compared to interferometric T-eff values. In that same T-eff range, ASPCAP metallicities are accurate to 0.18 dex between -1.0 <[M/H]< 0.2. For these cool dwarfs, nearly every colour is sensitive to both T-eff and metallicity. Notably, we find that g - r is not a good indicator of metallicity for near-solar metallicity early-M dwarfs. We confirm that J - K-S colour is strongly dependent on metallicity, and find that W1 - W2 colour is a promising metallicity indicator. Comparison of the late-K and early-M dwarf colours, metallicities, and T-eff to those from three different model grids shows reasonable agreement in r - z and J - K-S colours, but poor agreement in u - g, g - r, and W1 - W2. Comparison of the metallicities of the KM dwarf sample to those from previous colour-metallicity relations reveals a lack of consensus in photometric metallicity indicators for late-K and early-M dwarfs. We also present empirical relations for T-eff as a function of r - z colour combined with either [M/H] or W1 - W2 colour, and for [M/H] as a function of r - z and W1 - W2 colour. These relations yield T-eff to similar to 100 K and [M/H] to similar to 0.18 dex precision with colours alone, for T-eff in the range of 3550-4200 K and [M/H] in the range of -0.5-0.2.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/621724 |
| Date | 11 August 2016 |
| Creators | Schmidt, Sarah J., Wagoner, Erika L., Johnson, Jennifer A., Davenport, James R. A., Stassun, Keivan G., Souto, Diogo, Ge, Jian |
| Contributors | Univ Arizona, Dept Phys |
| Publisher | OXFORD UNIV PRESS |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society |
| Relation | http://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stw1139 |
Page generated in 0.0025 seconds