Revisiting TOI-4438 and TOI-442

This yields a refined planetary mass of Mp=4.11^+0.40^_-0.38_M_{Earth}_ and a radius of Rp=2.40^+0.09^_-0.10_R_{Earth}_, consistent with the previous estimate within 1.1 sigma while improving by 53% the precision on the mass and 22% on the radius. For TOI-442 b, we add 29 SPIRou RV measurements to an extensive archival dataset, significantly extending the temporal baseline. Incorporating this with a new TESS sector, we tighten the constraints on the planetary mass to Mp=28.38^+0.77^_-0.73_M_{Earth}_ and radius to Rp=4.25^+0.10^_-0.08_R_{Earth}_, which agrees to the previous values within 1.5 sigma and improves the precisions by 46% and 67% respectively.

We find no clear signs of additional planets in the currently available RV data, although we detect a single-transit event in the TOI-4438 light curve. We compare various RV models and find that those accounting for stellar variability-induced signals yield improved constraints on the planetary parameters.