IRS-TR 12003: Constructing Low-Resolution Truth Spectra of the Standard Stars HR 6348 and HD 173511

TL;DR

This paper presents the creation of calibrated low-resolution infrared spectra for two standard K giant stars, using IRS data and models, achieving high fidelity suitable for calibration purposes.

Contribution

It introduces a calibration method for IRS spectra of standard stars, addressing fringing and excess issues, and provides high-fidelity spectra for HR 6348 and HD 173511.

Findings

Spectroscopic fidelity of 0.5% below 29 μm for HR 6348

Fidelity of ~0.5% at all wavelengths below 35.8 μm for HD 173511

Calibration process mitigates fringing and red excess effects

Abstract

This report describes the generation of fully calibrated spectra of the K giants HR 6348 and HD 173511 from data obtained with the low-resolution modules of the Infrared Spectrograph (IRS), with an emphasis on the spectra from the Long-Low (LL) module. The spectra were calibrated using Kurucz models and IRS observations of the A dwarfs alpha Lac and delta UMi. The calibration process required mitigation for fringing in the first-order LL spectrum and a faint red excess in alpha Lac which may arise from a low-contrast debris disk. The final calibrated spectrum of HR 6348 has a spectroscopic fidelity of 0.5% or better below 29 um, with an uncertainty increasing to ~1% at 33-37 um. The final calibrated spectrum of HD 173511 has a spectroscopic fidelity of ~0.5% at all wavelengths below 35.8 um.