  Planetary systems around solar analogs inform us about how planets form and
evolve in Solar System-like environments. We report the detection and
characterization of two planetary systems around the solar analogs TOI-1736 and
TOI-2141 using TESS photometry data and spectroscopic data obtained with the
SOPHIE instrument on the 1.93 m telescope at the Observatoire de Haute-Provence
(OHP). We performed a detailed spectroscopic analysis of these systems to
obtain the precise radial velocities (RV) and physical properties of their host
stars. TOI-1736 and TOI-2141 each host a transiting sub-Neptune with radii of
$2.44\pm0.18$ R$_{\oplus}$ and $3.05\pm0.23$ R$_{\oplus}$, orbital periods of
$7.073088(7)$ d and $18.26157(6)$ d, and masses of $12.8\pm1.8$ M$_{\oplus}$
and $24\pm4$ M$_{\oplus}$, respectively. TOI-1736 shows long-term RV variations
that are consistent with a two-planet solution plus a linear trend of $-0.177$
ms$^{-1}$d$^{-1}$. We measured an RV semi-amplitude of $201.1\pm0.7$ ms$^{-1}$
for the outer companion, TOI-1736 c, implying a projected mass of
$m_{c}\sin{i}=8.09\pm0.20$ M$_{\rm Jup}$. From the GAIA DR3 astrometric excess
noise, we constrained the mass of TOI-1736 c at $8.7^{+1.5}_{-0.6}$ M$_{\rm
Jup}$. This planet is in an orbit of $570.2\pm0.6$ d with an eccentricity of
$0.362\pm0.003$ and a semi-major axis of $1.381\pm0.017$ au, where it receives
a flux of $0.71\pm0.08$ times the bolometric flux incident on Earth, making it
an interesting case of a supergiant planet that has settled into an eccentric
orbit in the habitable zone of a solar analog. Our analysis of the mass-radius
relation for the transiting sub-Neptunes shows that both TOI-1736 b and
TOI-2141 b likely have an Earth-like dense rocky core and a water-rich
envelope.
