New Substellar Discoveries from Kepler and K2: Is There a Brown Dwarf Desert?

We present the discoveries of a brown dwarf (BD) and a low-mass star from the Kepler and K2 missions. The newly discovered BD is EPIC 212036875b and the low-mass star is KOI-607b. EPIC 212036875b has a mass of M _b = 52.3 ± 1.9 M _J, a radius of R _b = 0.874 ± 0.017 R _J, and orbits its host star in P = 5.169885 ± 0.000027 days. Its host star is a late F-type star with M _⋆ = 1.288 ± 0.065 M _⊙, R _⋆ = 1.498 ± 0.025 R _⊙, and T _eff = 6238 ±60 K. KOI-607b has a mass of M _b = 95.1 ± 3.4 M _J, a radius of R _b = 1.089 ± 0.089 R _J, and an orbital period of P = 5.89399148 ± 0.00000060 days. The primary star in the KOI-607 system is a G dwarf with M _⋆ =0.993 ± 0.052 M _⊙, R _⋆ = 0.915 ± 0.031 R _⊙, and T _eff = 5418 ± 87 K. We also revisit a BD, CWW 89Ab, that was previously published by Nowak et al. (under the designation EPIC 219388192b). CWW 89Ab is one of two known transiting BDs associated with a star cluster, which illustrates the need for more BDs with accurate masses, radii, and reliable age determinations to test theoretical models. We find that the newly discovered BD, EPIC 212036875b, falls in the middle of the so-called BD desert, indicating that EPIC 212036875b is either a particularly rare object, or the BD desert may not be so dry after all.