The Empirical Relations between Accretion Luminosity and the Luminosity of Accretion Tracers: are we using them correctly?

The formation of low-mass stars is a complex and crucial process for understanding stellar evolution and planet formation. In the current scenario of low-mass star formation, after core collapse, the infalling material from the envelope is stored in the circumstellar disk. From this disk, the material reaches the forming star by following the star's magnetospheric lines. The energy released during this process, known as accretion luminosity (Lacc), plays a fundamental role in tracing the history of stellar mass accumulation. For decades, empirical relationships between Lacc and the luminosity of accretion tracers have been used to analyse young stars (Muzerolle et al.1998; Natta et al. 2004; Mohanty et al. 2005; Alcalá et al. 2017). In this talk, I will present new empirical relationship or accretion tracers from UVB to NIR, including the entire Brackett series, developed from the analysis of the Penellope XShooter dataset. This offers a more refined and comprehensive analysis compared to previous studies. I will discuss the limitations and strengths of this methodology as applied to both the protostellar phase and the pre-main sequence phase.