Fe i Lines in 0.91–1.33 μm Spectra of Red Giants for Measuring the Microturbulence and Metallicities

<jats:title>Abstract</jats:title> <jats:p>For a detailed analysis of stellar chemical abundances, high-resolution spectra in the optical have mainly been used, while the development of near-infrared (NIR) spectrograph has opened new wavelength windows. Red giants have a large number of resolved absorption lines in both the optical and NIR wavelengths, but the characteristics of the lines in different wave passbands are not necessarily the same. We present a selection of Fe <jats:sc>i</jats:sc> lines in the <jats:italic>z</jats:italic>′, <jats:italic>Y</jats:italic>, and <jats:italic>J</jats:italic> bands (0.91–1.33 <jats:italic>μ</jats:italic>m). On the basis of two different lists of lines in this range, the Vienna Atomic Line Database (VALD) and the catalog published by Meléndez & Barbuy in 1999 (MB99), we selected sufficiently strong lines that are not severely blended and compiled lists with 107 Fe <jats:sc>i</jats:sc> lines in total (97 and 75 lines from VALD and MB99, respectively). Combining our lists with high-resolution (<jats:italic>λ</jats:italic>/Δ<jats:italic>λ</jats:italic> = 28,000) and high signal-to-noise (>500) spectra taken with an NIR spectrograph, WINERED, we present measurements of the iron abundances of two prototype red giants: Arcturus and <jats:italic>μ</jats:italic> Leo. A bootstrap method for determining the microturbulence and abundance together with their errors is demonstrated. The standard deviations of <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab0ec4ieqn1.gif" xlink:type="simple"/> </jats:inline-formula> values from individual Fe <jats:sc>i</jats:sc> lines are significantly smaller when we use the lines from MB99 instead of those from VALD. With the MB99 list, we obtained <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab0ec4ieqn2.gif" xlink:type="simple"/> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab0ec4ieqn3.gif" xlink:type="simple"/> </jats:inline-formula> dex for Arcturus, and <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab0ec4ieqn4.gif" xlink:type="simple"/> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab0ec4ieqn5.gif" xlink:type="simple"/> </jats:inline-formula> dex for <jats:italic>μ</jats:italic> Leo. These final values show better agreements with previous values in the literature than the corresponding values we obtained with VALD.</jats:p>