Accretion rates of TW Hya from 25yrs sp. obs.

The primary goal of this paper is to analyze the stability over time of the mass accretion rate onto TW Hya, the nearest accreting solar-mass young star. We measure veiling across the optical spectrum in 1169 archival high-resolution spectra of TW Hya, obtained from 1998-2022.

The veiling is then converted to accretion rate using 26 flux- calibrated spectra that cover the Balmer jump. The accretion rate measured from the excess continuum has an average of 2.51x10^-9^M_{sun}_/yr and a Gaussian distribution with an FWHM of 0.22 dex. This accretion rate may be underestimated by a factor of up to 1.5 because of uncertainty in the bolometric correction and another factor of 1.7 because of excluding the fraction of accretion energy that escapes in lines, especially Ly{alpha}.