Near-infrared Spectral Characterization of Solar-type Stars in the Northern Hemisphere

TL;DR

This study characterizes 184 solar-analog stars in the near-infrared range (0.8-4.2 microns) to improve calibration standards for solar system observations, identifying 145 reliable analogs suitable for calibration purposes.

Contribution

It provides a comprehensive near-infrared spectral catalog of solar-analog stars, including classification into reliable, usable, and unsuitable categories, expanding calibration options beyond visible wavelengths.

Findings

145 stars classified as reliable solar analogs

18 stars deemed unsuitable for calibration

Most reliable analogs are consistent from 2.5 to 4.2 microns

Abstract

Although solar-analog stars have been studied extensively over the past few decades, most of these studies have focused on visible wavelengths, especially those identifying solar-analog stars to be used as calibration tools for observations. As a result, there is a dearth of well-characterized solar analogs for observations in the near-infrared, a wavelength range important for studying solar system objects. We present 184 stars selected based on solar-like spectral type and V-J and V-K colors whose spectra we have observed in the 0.8-4.2 micron range for calibrating our asteroid observations. Each star has been classified into one of three ranks based on spectral resemblance to vetted solar analogs. Of our set of 184 stars, we report 145 as reliable solar-analog stars, 21 as solar analogs usable after spectral corrections with low-order polynomial fitting, and 18 as unsuitable for use as calibration standards owing to spectral shape, variability, or features at low to medium resolution. We conclude that all but 5 of our candidates are reliable solar analogs in the longer wavelength range from 2.5 to 4.2 microns. The average colors of the stars classified as reliable or usable solar analogs are V-J=1.148, V-H=1.418, and V-K=1.491, with the entire set being distributed fairly uniformly in R.A. across the sky between -27 and +67 degrees in decl.