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تسجيل مستخدم جديدWASP-166b: a bloated super-Neptune transiting a V = 9 star
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We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 Mjup (1.9 Mnep) and a bloated radius of 0.63 Rjup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar rotation axis (sky-projected obliquity angle lambda = 3 +/- 5 degrees). Variations in the radial-velocity measurements are likely the result of magnetic activity over a 12-d stellar rotation period. WASP-166b appears to be a rare object within the ``Neptune desert.
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Planet formation processes or evolution mechanisms are surmised to be at the origin of the hot Neptune desert. Studying exoplanets currently living within or at the edge of this desert could allow disentangling the respective roles of formation and e
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We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by the TESS space mission in Sectors 5 and 6. We performed ground-based f
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IW ../submit_V2/abstract.txt ( Row 1 Col 1 6:48 Ctrl-K H for help We report the discovery by the HATSouth network of HATS-7b, a transiting Super-Neptune with a mass of 0.120+/-0.012MJ, a radius of 0.563+/-(0.046,0.034)RJ, and an orbital period of 3.1
853days. The host star is a moderately bright (V=13.340+/-0.010mag, K_S=10.976+/-0.026mag) K dwarf star with a mass of 0.849+/-0.027Msun , a radius of 0.815+/-(0.049,-0.035)Rsun, and a metallicity of [Fe/H]=+0.250+/-0.080. The star is photometrically quiet to within the precision of the HATSouth measurements and has low RV jitter. HATS-7b is the second smallest radius planet discovered by a wide-field ground-based transit survey, and one of only a handful of Neptune-size planets with mass and radius determined to 10% precision. Theoretical modeling of HATS-7b yields a hydrogen-helium fraction of 18+/-4% (rock-iron core and H2-He envelope), or 9+/-4% (ice core and H2-He envelope), i.e.it has a composition broadly similar to that of Uranus and Neptune, and very different from that of Saturn, which has 75% of its mass in H2-He. Based on a sample of transiting exoplanets with accurately (<20%) determined parameters, we establish approximate power-law relations for the envelopes of the mass-density distribution of exoplanets. HATS-7b, which, together with the recently discovered HATS-8b, is one of the first two transiting super-Neptunes discovered in the Southern sky, is a prime target for additional follow-up observations with Southern hemisphere facilities to characterize the atmospheres of Super-Neptunes (which we define as objects with mass greater than that of Neptune, and smaller than halfway between that of Neptune and Saturn, i.e. 0.054 MJ<Mp<0.18 MJ).
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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transiting exoplanet to be discovered from a wide-field ground based search, and with a mass of 0.138 $pm$ 0.019 M$_J$ it is approximately half-way between the masses of Neptune and Saturn. However HATS-8b has a radius of 0.873 (+0.123,-0.075) R$_J$, resulting in a bulk density of just 0.259 $pm$ 0.091 g.cm$^{-3}$. The metallicity of the host star is super-Solar ([Fe/H]=0.210 $pm$ 0.080), arguing against the idea that low density exoplanets form from metal-poor environments. The low density and large radius of HATS-8b results in an atmospheric scale height of almost 1000 km, and in addition to this there is an excellent reference star of near equal magnitude at just 19 arcsecond separation on the sky. These factors make HATS-8b an exciting target for future atmospheric characterization studies, particularly for long-slit transmission spectroscopy.
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