Small and rocky worlds orbiting M dwarfs: GJ 3473 b and GJ 3929 b

We present two small transiting planets with mass measurements orbiting bright mid M dwarfs (GJ 3473, GJ 3929). GJ 3473 b (Kemmer et al. 2020) is a hot, presumably rocky, planet (P = 1.198 d, M_b = 1.86 ± 0.30 M_e, and radius, R_b = 1.264 ± 0.050 R_e), which is due to its high temperature a particularly attractive target for thermal emission spectroscopy. Further, it is accompanied by another non-transiting planet (Pc = 15.509 ± 0.033 d) that has a minimum mass of M_c sin i = 7.41 ± 0.91 M_e. For GJ 3929 b (in prep.) we present a preliminary analysis that yields a period of P = 2.616 d, mass M_b = 2.03 ± 0.59 M_e, and radius, R_b = 1.155 ± 0.043 R_e. The radial velocity data show evidence for another signal, whose origin is, however, not yet clarified.
Both systems add to the TESS level-one science goal to measure the masses for 50 transiting planets with radii smaller than 4 R_e.