Characterizing the Low-Mass Pre-Main-Sequence Population in the Low-Metallicity Star-Forming Region Dolidze 25 Using VLT-MUSE

TL;DR

This study investigates low-mass pre-main sequence stars in the metal-poor cluster Dolidze 25 using VLT-MUSE, revealing that accretion rates are similar to solar-metallicity regions and emphasizing the need for metallicity-matched models for accurate stellar characterization.

Contribution

First spectroscopic analysis of low-mass PMS stars in a low-metallicity environment using VLT-MUSE, highlighting the importance of metallicity-matched models for accurate parameter estimation.

Findings

Mass accretion rates are comparable to solar-metallicity regions.

Using solar-metallicity templates overestimates stellar temperatures and extinctions.

Flux-calibrated spectra provided as a resource for future studies.

Abstract

The metallicity of the star-forming environment is a fundamental parameter shaping the evolution of protoplanetary disks and the formation of planetary systems, yet its influence remains poorly constrained. We present a spectroscopic study of low-mass pre-main sequence (PMS) stars ($M < 1 \, M_\odot$) in the exceptionally metal-poor cluster Dolidze~25 ($Z \approx 0.2 \, Z_\odot$), using VLT/MUSE observations to probe accretion processes and disk evolution in a subsolar environment. We identify 132 cluster members using a combination of \textit{Gaia} astrometry and spectroscopic youth indicators, including lithium absorption and Balmer emission. The stellar parameters are derived using low-metallicity BT-Settl models yielding effective temperatures, extinctions, luminosities enabling robust estimates of stellar masses and ages. Mass accretion rates ($\dot{M}_\mathrm{acc}$) derived from H$\alpha$ emission span $10^{-10}$--$10^{-8} \, M_\odot\,\mathrm{yr}^{-1}$ with a median value of \(8 \times 10^{-10}\,M_\odot\,\mathrm{yr}^{-1}\). These rates are comparable to those in solar-metallicity regions of similar age, such as Lupus and Orion, indicating minimal metallicity dependence in accretion processes. Our analysis shows that using solar-metallicity templates to fit low-metallicity stars leads to systematic overestimations of \(T_\mathrm{eff}\) (by approximately \(300\,\mathrm{K}\)) and \(A_V\) (by around \(0.5\,\mathrm{mag}\)), underscoring the importance of employing metallicity-matched models for reliable characterization in low-\(Z\) environments. We present flux-calibrated, extinction-corrected spectra of these metal-poor PMS stars as a valuable resource for future investigations of disk evolution in subsolar regimes.