The First Infrared Portrait of A Solar-Like Host Star with Debris Disk: Pioneering High-Resolution H- and K-Band Spectroscopy of HD115617 with Comparative Optical Spectrum Analysis

TL;DR

This study presents the first high-resolution infrared spectrum of a solar-like star with a debris disk, comparing optical and NIR data to understand stellar parameters and composition, highlighting methodological challenges.

Contribution

It introduces a combined optical and NIR spectroscopic approach with a new calibrated line list to analyze stellar parameters and composition of HD115617.

Findings

Optical and NIR spectra yield different effective temperatures for HD115617.

Asteroseismic data confirms the star's main-sequence status and solar-like composition.

No chemical signature of planetary formation was detected in the star's composition.

Abstract

We present the first high-resolution near-infrared spectroscopic analysis of the solar analog HD115617 (61 Virginis), complemented by optical spectroscopy, asteroseismology, and spectral energy distribution modeling. Using ESPRESSO and IGRINS spectra with a newly calibrated NIR line list, we derived atmospheric parameters that revealed notable differences between spectral regions: the optical analysis yielded Teff = 5500 +- 140 K, log g = 4.40 +- 0.16, and solar metallicity, whereas the NIR yielded Teff = 5750 +- 140 K. We tested this 250 K discrepancy using the independent line depth ratio (LDR) method for both spectra. When applied to the optical lines, LDR confirmed the cooler scale (5553 +- 73 K); for the NIR lines, it provided an intermediate temperature (5636 +- 15 K). Asteroseismic scaling with TESS data yielded a radius of 0.98 +- 0.09 R_sun, consistent with SED fitting and confirming the star's main-sequence solar-like status. However, the age estimates diverged between methods, with optical and NIR analyses yielding ages of 10.97 and 8.04 Gyr, respectively. Critically, a condensation temperature analysis revealed no significant trend, confirming the star's bulk solar-like composition and showing no chemical signature of planetary formation processes. Kinematic diagnostics place HD115617 in the thin Galactic disk, with a birth radius of approximately 5.7-8.0 kpc. Although the spectral differences may be linked to the star's multi-planet system or debris disk, our analysis highlights the critical challenge of distinguishing such effects from methodological systematics in multi-wavelength studies. Consequently, we propose a systematic, homogeneous optical-NIR survey of solar-type stars to resolve this ambiguity, which could ultimately inform novel indirect methods for characterizing stellar environments.