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Arxiv: Determining stellar accretion rates from Pa_α and Br_β emission lines with JWST NIRSpec Published: 3/14/2024 6:59:02 PM Updated: 3/14/2024 6:59:02 PM

Paper abstract: In this letter we present the first systematic spectroscopic measurements ofthe Near-InfraRed (NIR) hydrogen recombination lines Pa_{\alpha} (\lambda =1.875 \mu m) and Br_{\beta} (\lambda = 2.626 \mu m), produced by pre-mainsequence (PMS) stars. These stars, consisting of T Tauri and Herbig AeBe starsare located in the massive Galactic star-formation region NGC 3603. Themeasurements were obtained from JWST NIRSpec, using multi-object spectroscopy(MOS) mode. Utilising existing empirical relations between L_{acc} andL_{Br_{\gamma}}, we have used our new measurements to formulate, for thefirst time, an empirical relationship between the accretion luminosityL_{acc} of the stars, and the line luminosities L_{line} of bothPa_{\alpha} and Br_{\beta}. These relationships are: \log_{10}(\frac{L_{acc}}{L_{\odot}}) = 1.42 (\pm 0.18) \times \log_{10}(\frac{L_{Pa_{\alpha}}}{L_{\odot}}) + 3.33 (\pm 0.42) and \log_{10}(\frac{L_{acc}}{L_{\odot}}) = 1.47 (\pm 0.18) \times \log_{10}(\frac{L_{Br_{\beta}}}{L_{\odot}}) + 4.60 (\pm 0.57). These new relationshipsare key for roughly estimating the accretion rates for large samples of PMSstars with JWST.