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Colloquium
The Unnoticed Impact of Magnetism on Temperatures and Masses of Young Stars

Abstract

The mass of a star is its most important property because it determines its evolution and defines its temperature, internal structure, and size throughout its life. Robust mass measurements are, therefore, essential for our understanding of stellar evolution and are crucial to studies of disk and planet formation, stellar populations, and more. Measuring a star's temperature from optical observations is often the easiest way to determine its mass. However, this traditional approach ignores the strong magnetism of young stars, which produces dark and bright spots on their surfaces. Recently, infrared studies have revealed that starspots can significantly affect the surface temperature of stars, raising concerns about the reliability of previous mass measurements. In this talk, I present the results of an infrared spectroscopic survey focused on the impact of magnetism on T Tauri stars. Specifically, I will describe how magnetic-induced starspots produce a systematic change in the temperature measurement of low-mass young stars. Additionally, using observations from ALMA, I will discuss whether optical or infrared observations are more reliable when deriving stellar masses from stellar evolutionary models.