TOI 1246 is one of only eight four-planet systems with measured masses and radii for all four planets. TESS observed this moderately bright K dwarf (V=11.6, K=9.9) for 12 sectors, and found four transiting planets. We collected 90 RV observations with Keck/HIRES and TNG/HARPS-N, many of which were contemporaneous with TESS photometry. We refit the photometry to refine planet radii, measure masses for all four planets, and find a surprising range of masses and densities. This system is brighter 93% of other four planet systems, and is a particularly interesting testing ground for mass loss and formation hypotheses due to the high planet multiplicity and varied planet masses.

{"references": ["Tamayo, Daniel et al. (2020), arXiv:2007.06521"]}