Exoplanets can evolve significantly between birth and maturity as their atmospheres , orbits , and structures are shaped by their environment .
Young planets ( < 1 Gyr ) offer the opportunity to probe these sculpting processes .
However , most of the known young planets orbit prohibitively faint stars .
We present the discovery of two planets transiting HD 63433 ( TOI 1726 , TIC 130181866 ) , a young Sun-like ( M _ { * } = 0.99 \pm 0.03 ) star .
Through kinematics , lithium abundance , and rotation , we confirm that HD 63433 is a member of the Ursa Major moving group ( \tau = 414 \pm 23 Myr ) .
Based on the TESS light curve and updated stellar parameters , the planet radii are 2.15 \pm 0.10 R _ { \oplus } and 2.67 \pm 0.12 R _ { \oplus } , the orbital periods are 7.11 and 20.55 days , and the orbital eccentricities are lower than abut 0.2 .
Using HARPS-N velocities , we measure the Rossiter-McLaughlin signal of the inner planet , demonstrating the orbit is prograde .
Since the host star is bright ( V=6.9 ) , both planets are amenable to transmission spectroscopy , radial velocity measurements of their masses , and more precise determination of the stellar obliquity .
This system is therefore poised to play an important role in our understanding of planetary system evolution in the first billion years after formation .