A sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)

[Abridged] We exploit the extreme radial velocity (RV) precision of ultra-stable echelle spectrograph ESPRESSO on VLT to unveil physical properties transiting sub-Neptune TOI-130 b, uncovered by TESS orbiting nearby, bright, late F-type star HD 5278 (TOI-130) with a period $P_{\rm b}=14.3$. use 43 high-resolution spectra and broad-band photometry information derive accurate stellar atmospheric parameters 5278. light curve (LC) spectroscopic diagnostics gauge impact activity RVs. perform joint RVs + LC analysis using fully Bayesian frameworks determine system parameters. The updated are T$_\mathrm{eff}=6203\pm64$ K, $\log g =4.50\pm0.11$ dex, [Fe/H]=$-0.12\pm0.04$ M$_\star=1.126_{-0.035}^{+0.036}$ M$_\odot$ R$_\star=1.194_{-0.016}^{+0.017}$ R$_\odot$. b's mass radius be $M_{\rm b} = 7.8_{-1.4}^{+1.5}$ M$_\oplus$ $R_{\rm 2.45\pm0.05$ R$_\oplus$. derived mean density, $\varrho_{\rm 2.9_{-0.5}^{+0.6}$ cm$^{-3}$, is consistent bulk composition substantial ($\sim30\%$) water fraction gas envelope comprising $\sim17\%$ measured radius. Given host brightness irradiation levels, b one best targets G-F primaries for follow-up characterization measurements HST JWST. discover second, non-transiting companion in system, c}=40.87_{-0.17}^{+0.18}$ days minimum c}\sin i_{\rm c} =18.4_{-1.9}^{+1.8}$ M$_\oplus$. study emerging trends growing population sub-Neptunes, provide statistical evidence low occurrence close-in, $10-15$ companions around $T_\mathrm{eff}\gtrsim5500$ K.