TOI-2525 b and c: A Pair of Massive Warm Giant Planets with Strong Transit Timing Variations Revealed by TESS*

TOI-2525 is a K-type star with an estimated mass of M = 0.849$_{-0.033}^{+0.024}$ M$_\odot$ and radius R 0.785$_{-0.007}^{+0.007}$ R$_\odot$ observed by the TESS mission in 22 sectors (within 1 39). The light curves yield significant transit events two companions, which show strong timing variations (TTVs) semi-amplitude $\sim$6 hours. We performed TTV dynamical, photo-dynamical curve analysis data, combined radial velocity (RV) measurements from FEROS PFS, we confirmed planetary nature these companions. system consists transiting pair planets comparable to Neptune Jupiter dynamical masses $m_{\rm b}$ 0.088$_{-0.004}^{+0.005}$ M$_{\rm Jup.}$, c}$ 0.709$_{-0.033}^{+0.034}$ $r_b$ 0.88$_{-0.02}^{+0.02}$ R$_{\rm Jup.}$ $r_c$ 0.98$_{-0.02}^{+0.02}$ orbital periods $P_{\rm 23.288$_{-0.002}^{+0.001}$ days 49.260$_{-0.001}^{+0.001}$ for inner outer planet, respectively. period ratio close 2:1 commensurability, but simulations suggest that it outside mean motion resonance (MMR) configuration. b among lowest density Neptune-mass known date, median $\rho_{\rm 0.174$_{-0.015}^{+0.016}$ g\,cm$^{-3}$. very similar other K-dwarf systems discovered TESS, TOI-2202 TOI-216, are composed almost identical primary warm giant near MMR.