Speaker
Description
In this work, we empirically calibrate the metallicity using wide binaries with a F, G, or K dwarf and a M dwarf companions. With 1409 FGK+M wide binaries well observed by LAMOST, we are able to calibrate M dwarf’s [Fe/H] by using the Stellar LAbel Machine (SLAM) model, which is a data-driven method based on support vector regression. The [Fe/H] labels of the training data are from FGK companions in the range of [-1,0.5] dex. And the Teff s are selected from Li et al. (2021), spanning [3100,4400] K. The uncertainties of [Fe/H] and Teff estimated by SLAM are ∼0.15 dex and ∼40 K, respectively, at snri >100. We applied the trained SLAM model to determine the [Fe/H] and Teff for ∼750,000 M dwarfs with low-resolution spectra in LAMOST DR9. Compared to other literature also using FGK+M wide binaries for calibration, our [Fe/H] estimates show no bias but a scatter of 0.13∼0.19 dex. However, the [Fe/H] compared to APOGEE shows a systematic difference of 0.15∼0.18 dex with a scatter of 0.15∼0.23 dex. While the Teff compared to APOGEE has a bias of 3 K with a scatter of 67 K, it is systematically higher by 183 K compared to other literature calibrated by the bolometric temperature.
