New HIRES radial velocity data for V1298 Tau

However, young stars tend to be extremely variable in both photometry and radial velocity (RV) measurements, which makes constraining these properties challenging. The V1298 Tau system of four ~0.5RJup planets transiting a pre-main-sequence star presents an important, if stress-inducing, opportunity to observe and measure directly the properties of infant planets.

Suarez Mascareno et al. published radial-velocity-derived masses for two of the V1298-Tau planets using a state-of-the-art Gaussian process regression framework. The planetary densities computed from these masses were surprisingly high, implying extremely rapid contraction after formation in tension with most existing planet-formation theories. In an effort to constrain further the masses of the V1298-Tau planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with published RVs and photometry.