Speaker
Description
Optical intensity interferometry is emerging as a powerful technique for directly measuring the angular sizes of early-type stars. The MAGIC telescopes host the MAGIC-SII (Stellar Intensity Interferometer) system, implemented to investigate the feasibility and scientific potential of this technique on Imaging Atmospheric Cherenkov Telescopes. Following the first successful measurements in 2019 and the extension of the system to the first Large-Sized Telescope (LST-1) in 2024, a large sample of OBA stars has been observed at blue wavelengths.
For several tens of these targets, the acquired data allow for angular diameter measurements with good precision of at least 5%. We are currently carrying out a population study of 45 OBA stars, grouped according to spectral type and luminosity class. For each target, we analyse both the interferometric observables and their optical spectra, enabling a systematic comparison of stars with different physical properties and evolutionary stages.
In this contribution, we present the methodology adopted for this study and its current status. The interferometric and spectroscopic observations will be compared with measurements available in the literature, including existing compilations of directly measured stellar diameters. This comparison will place the MAGIC+LST-1 targets in the broader context of resolved stellar populations and quantify the contribution of intensity interferometry to the expansion of the parameter space of stellar characterization with the addition of direct angular diameter measurements. This is crucial for extending and constraining the validity of stellar modelling libraries to the frontier of current catalogs, where data is still lacking.
