F, G, K, M Spectral Standards in the Y Band (0.95-1.11 um)

TL;DR

This paper provides a high-resolution spectral atlas and catalog of atomic and molecular features for F, G, K, and M stars in the 0.95-1.11 um range, aiding stellar classification and parameter diagnostics.

Contribution

It introduces a new spectral standards grid and a detailed catalog of absorption features in the near-infrared, with analysis of temperature and gravity diagnostics near 1 um.

Findings

Identified key line ratios for spectral typing.

Cataloged atomic and molecular features in the 0.95-1.11 um range.

Analyzed excitation potential, line depth, and equivalent width trends.

Abstract

We take advantage of good atmospheric transparency and the availability of high quality instrumentation in the 1 um near-infrared atmospheric window to present a grid of F, G, K, and M spectral standards observed at high spectral resolution (R ~ 25,000). In addition to a spectral atlas, we present a catalog of atomic line absorption features in the 0.95-1.11 um range. The catalog includes a wide range of line excitation potentials, from 0-13 eV, arising from neutral and singly ionized species, most frequently those of Fe I and Ti I at low excitation, Cr I, Fe I, and Si I at moderate excitation, and C I, S I, and Si I having relatively high excitation. The spectra also include several prominent molecular bands from CN and FeH. For the atomic species, we analyze trends in the excitation potential, line depth, and equivalent width across the grid of spectroscopic standards to identify temperature and surface gravity diagnostics near 1 um. We identify the line ratios that appear especially useful for spectral typing as those involving Ti I and C I or S I, which are temperature sensitive in opposite directions, and Sr II, which is gravity sensitive at all spectral types. Ascii versions of all spectra are available to download with the electronic version of the journal.