We report the discovery of two transiting planetary systems: a super dense, sub-Jupiter mass planet WASP-86b (mpl = 0.82 $pm$ 0.06 mj, rpl = 0.63 $pm$ 0.01 rj), and a bloated, Saturn-like planet WASP-102b (mpl = 0.62 $pm$ 0.04 mj, rpl=1.27 $pm$ 0.03 rj). They orbit their host star every $sim$5.03, and $sim$2.71 days, respectively. The planet hosting WASP-86 is a F7 star (teff = 6330$pm$110 K, feh = $+$0.23 $pm$ 0.14 dex, and age $sim$0.8--1~Gyr), WASP-102 is a G0 star (teff = 5940$pm$140 K, feh = $-$0.09$pm$ 0.19 dex, and age $sim$1~Gyr). These two systems highlight the diversity of planetary radii over similar masses for giant planets with masses between Saturn and Jupiter. WASP-102b shows a larger than model-predicted radius, indicating that the planet is receiving a strong incident flux which contributes to the inflation of its radius. On the other hand, with a density of $rho_{pl}$ = 3.24$pm$~0.3~$rho_{jup}$, WASP-86b is the densest gas giant planet among planets with masses in the range 0.05 $<M$_{pl}$<$ 2.0 mj. With a stellar mass of 1.34 M$_{odot}$ and feh = $+$0.23 dex, WASP-86 could host additional massive and dense planets given that its protoplanetary disc is expected to also have been enriched with heavy elements. In order to match WASP-86bs density, an extrapolation of theoretical models predicts a planet composition of more than 80% in heavy elements (whether confined in a core or mixed in the envelope). This fraction corresponds to a core mass of approximately 210me for WASP-86bs mass of mpl$sim$260,me. Only planets with masses larger than about 2mj have larger densities than that of WASP-86b, making it exceptional in its mass range.
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