Abstract: As an all-sky survey, NASA’s Transiting Exoplanet Survey Satellite (TESS) mission is able to detect the brightest and rarest types of transiting planetary systems, including young planets that enable study of the evolutionary processes that occur within the first billion years. Here we report the discovery of a young, multiplanet system orbiting the bright K4.5V star, TOI-712 (V = 10.838, , R ⋆ = 0.674 ± 0.016 R ⊙, K). From the TESS light curve, we measure a rotation period of 12.48 days and derive an age between about 500 Myr and 1.1 Gyr. The photometric observations reveal three transiting mini-Neptunes (, , ), with orbital periods of P b = 9.531 days, P c = 51.699 days, and P d = 84.839 days. After modeling the three-planet system, an additional Earth-sized candidate is identified, TOI-712.05 (P = 4.32 days, R P = 0.81 ± 0.11 R ⊕). We calculate that the habitable zone falls between 0.339 and 0.844 au (82.7 and 325.3 days), placing TOI-712 d near its inner edge. Among planetary systems harboring temperate planets, TOI-712 (T = 9.9) stands out as a relatively young star bright enough to motivate further characterization.

Abstract: Mature super-Earths and sub-Neptunes are predicted to be ≃ Jovian radius when younger than 10 Myr. Thus, we expect to find 5–15 R ⊕ planets around young stars even if their older counterparts harbor none. We report the discovery and validation of TOI 1227b, a 0.85 ± 0.05 R J (9.5 R ⊕) planet transiting a very-low-mass star (0.170 ± 0.015 M ⊙) every 27.4 days. TOI 1227's kinematics and strong lithium absorption confirm that it is a member of a previously discovered subgroup in the Lower Centaurus Crux OB association, which we designate the Musca group. We derive an age of 11 ± 2 Myr for Musca, based on lithium, rotation, and the color–magnitude diagram of Musca members. The TESS data and ground-based follow-up show a deep (2.5%) transit. We use multiwavelength transit observations and radial velocities from the IGRINS spectrograph to validate the signal as planetary in nature, and we obtain an upper limit on the planet mass of ≃0.5 M J. Because such large planets are exceptionally rare around mature low-mass stars, we suggest that TOI 1227b is still contracting and will eventually turn into one of the more common <5 R ⊕ planets.

Abstract: TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations (TTVs). Precise characterization of the planets’ masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV baseline from TESS and an ongoing ground-based transit observing campaign increase the precision of the mass and eccentricity measurements. We determine that TOI-216c is a warm Jupiter, TOI-216b is an eccentric warm Neptune, and that they librate in 2:1 resonance with a moderate libration amplitude of deg, a small but significant free eccentricity of for TOI-216b, and a small but significant mutual inclination of 1.°2–3.°9 (95% confidence interval). The libration amplitude, free eccentricity, and mutual inclination imply a disturbance of TOI-216b before or after resonance capture, perhaps by an undetected third planet.

Abstract: Premise of the study: While plants show lineage-specific differences in metabolite composition, plant metabolites are also known to vary in response to the environment. The extent to which these different determinants of metabolite composition are mutually independent and recognizable is unknown. Moreover, the extent to which the metabolome can reconcile evolutionary constraint with the needs of the plant for rapid environmental response is unknown. We investigated these questions in plant species representing different phylogenetic lineages and growing in different subantarctic island environments. We studied their aminesmetabolites involved in plant response to environmental conditions. Methods: Nine species were sampled under high salinity, water saturation, and altitude on the Kerguelen Islands. Their profiles of free aromatic, aliphatic, and acetyl-conjugated amines were determined by HPLC. We related amine composition to species and environment using generalized discriminant analyses. Key results: Amine composition differed significantly between species within the same environment, and the differences reflected phylogenetic positions. Moreover, across all species, amine metabolism differed between environments, and different lineages occupied different absolute positions in amine/environment space. Interestingly, all species had the same relative shifts in amine composition between environments. Conclusion: Our results indicate a similar response of amine composition to abiotic environments in distantly related angiosperms, suggesting environmental flexibility of species is maintained despite major differences in amine composition among lineages. These results aid understanding of how in nature the plant metabolome integrates ecology and evolution, thus providing primordial information on adaptive mechanisms of plant metabolism to climate change.

Abstract: Tide gauge measurements provide data for routine tidal predictions in ports as well as for extreme events such as storm surges and tsunamis. Along with satellite altimeter measurements, tide gauges also provide measurements used for sea-level rise estimates. This is particularly important for impact assessment in low-lying coastlines of south Asia as well as islands such as the Maldives in the Indian Ocean.