Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data

Context. The TOI-421 planetary system contains two sub-Neptune-type planets (Pb ~ 5.2 days, Teqb ~ 900 K, and Pc ~ 16.1 days, Teq,c ~ 650 K) and is a prime target to study the formation and evolution of planets and their atmospheres. The inner planet is especially interesting as the existence of a hydrogen-dominated atmosphere at its orbital separation cannot be explained by current formation models without previous orbital migration. Aims. We aim to improve the system parameters to further use them to model the interior structure and simulate the atmospheric evolution of both planets, to finally gain insights into their formation and evolution. We also investigate the possibility of detecting transit timing variations (TTVs). Methods. We jointly analysed photometric data of three TESS sectors and six CHEOPS visits as well as 156 radial velocity data points to retrieve improved planetary parameters. We also searched for TTVs and modelled the interior structure of the planets. Finally, we simulated the evolution of the primordial H-He atmospheres of the planets using two different modelling frameworks. Results. We determine the planetary radii and masses of TOI-421 b and c to be Rb = 2.64 ± 0.08 R, Mb = 6.7 ± 0.6 M, Rc = 5.09 ± 0.07 R, and Mc = 14.1 ± 1.4 M. Using these results we retrieved average planetary densities of ρb = 0.37 ± 0.05ρ and ρc = 0.107 ± 0.012 ρ. We do not detect any statistically significant TTV signals. Assuming the presence of a hydrogen-dominated atmosphere, the interior structure modelling results in both planets having extensive envelopes. While the modelling of the atmospheric evolution predicts for TOI-421 b to have lost any primordial atmosphere that it could have accreted at its current orbital position, TOI-421 c could have started out with an initial atmospheric mass fraction somewhere between 10 and 35%. Conclusions. We conclude that the low observed mean density of TOI-421 b can only be explained by either a bias in the measured planetary parameters (e.g. driven by high-altitude clouds) and/or in the context of orbital migration. We also find that the results of atmospheric evolution models are strongly dependent on the employed planetary structure model

Efeito de dietas artificiais para a alimentação de adultos de Bonagota cranaodes (Meyrick) (Lepidoptera: Tortricidae), em laboratório Effect of artificial diets for the adults of Bonagota cranaodes feeding (Meyrick) (Lepidoptera: Tortricidae), in laboratory

Adultos de Bonagota cranaodes (Meyrick) (Lepidoptera: Tortricidae) submetidos a tratamentos com água, solução de mel a 10%, solução de mel a 10% + 25% de cerveja e sem alimento foram mantidos em gaiolas de PVC transparente para avaliar a fecundidade, longevidade e viabilidade de ovos em laboratório a 25&plusmn;1&deg;C e 70&plusmn;10% de UR. Maior longevidade de fêmeas e machos e número de ovos/fêmea foram obtidos nos substratos compostos de mel a 10% (17,75 dias, 17,35 dias e 14,07 ovos/postura) e mel a 10% + 25% de cerveja (18,25 dias, 18,20 dias e 12,71 ovos/postura). A viabilidade dos ovos e a duração do período embrionário foram semelhantes em todos os tratamentos. O substrato alimentar mel a 10% + 25% de cerveja, apresentou efeitos semelhantes ao substrato composto de apenas mel a 10% sobre a longevidade, fertilidade e viabilidade dos ovos. Entretanto, devido ao menor custo, a dieta a base de mel apresenta melhor potencial de utilização para manutenção da criação do inseto em laboratório.<br>Adults of Bonagota cranaodes (Meyrick) (Lepidoptera: Tortricidae) were maintained in cages of transparent PVC without food, with water, and fed with honey solution at 10% and with honey solution at 10% + 25% of beer only with water and without feeding to evaluate their fecundity, longevity and viability of eggs in growth to (25&plusmn;1&deg;C and 70&plusmn;10% of RU). The longevity of females and males was longer and number of eggs/female were obtained in the mean substratum composed of honey at 10% (17,75 days, 17,35 days and 14,07 eggs/posture) and honey at 10% + 25% of beer (18,25 days, 18,20 days and 12,71 eggs/posture). The viability of the eggs and the duration of the embryonic period was similar in all the treatments. The mean with honey at 10% + 25% of beer, presented effects similar to the mean composed with honey at 10% regarding to the longevity, fertility and viability of eggs of B. cranaodes. However, due to the lower cost, the diet based only in honey represents the best choice in laboratory for maintenance rearing of this insect

Phase curve and geometric albedo of WASP-43b measured with CHEOPS, TESS, and HST WFC3/UVIS

Context. Observations of the phase curves and secondary eclipses of extrasolar planets provide a window onto the composition and thermal structure of the planetary atmospheres. For example, the photometric observations of secondary eclipses lead to the measurement of the planetary geometric albedo, Ag, which is an indicator of the presence of clouds in the atmosphere. Aims. In this work, we aim to measure the Ag in the optical domain of WASP-43b, a moderately irradiated giant planet with an equilibrium temperature of ~1400 K. Methods. For this purpose, we analyzed the secondary eclipse light curves collected by CHEOPS together with TESS along with observations of the system and the publicly available photometry obtained with HST WFC3/UVIS. We also analyzed the archival infrared observations of the eclipses and retrieve the thermal emission spectrum of the planet. By extrapolating the thermal spectrum to the optical bands, we corrected for the optical eclipses for thermal emission and derived the optical Ag. Results. The fit of the optical data leads to a marginal detection of the phase-curve signal, characterized by an amplitude of 160 ± 60 ppm and 80a-? 50+60 ppm in the CHEOPS and TESS passbands, respectively, with an eastward phase shift of ~50 (1.5Ï ? detection). The analysis of the infrared data suggests a non-inverted thermal profile and solar-like metallicity. The combination of the optical and infrared analyses allows us to derive an upper limit for the optical albedo of Ag< 0.087, with a confidence of 99.9%. Conclusions. Our analysis of the atmosphere of WASP-43b places this planet in the sample of irradiated hot Jupiters, with monotonic temperature-pressure profile and no indication of condensation of reflective clouds on the planetary dayside.ISSN:0004-6361ISSN:1432-074

Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b

Context: WASP-76 b has been a recurrent subject of study since the detection of a signature in high-resolution transit spectroscopy data indicating an asymmetry between the two limbs of the planet. The existence of this asymmetric signature has been confirmed by multiple studies, but its physical origin is still under debate. In addition, it contrasts with the absence of asymmetry reported in the infrared (IR) phase curve. Aims: We provide a more comprehensive dataset of WASP-76 b with the goal of drawing a complete view of the physical processes at work in this atmosphere. In particular, we attempt to reconcile visible high-resolution transit spectroscopy data and IR broadband phase curves. Methods: We gathered 3 phase curves, 20 occultations, and 6 transits for WASP-76 b in the visible with the CHEOPS space telescope. We also report the analysis of three unpublished sectors observed by the TESS space telescope (also in the visible), which represents 34 phase curves. Results: WASP-76 b displays an occultation of 260 ± 11 and 152 ± 10 ppm in TESS and CHEOPS bandpasses respectively. Depending on the composition assumed for the atmosphere and the data reduction used for the IR data, we derived geometric albedo estimates that range from 0.05 ± 0.023 to 0.146 ± 0.013 and from &lt;0.13 to 0.189 ± 0.017 in the CHEOPS and TESS bandpasses, respectively. As expected from the IR phase curves, a low-order model of the phase curves does not yield any detectable asymmetry in the visible either. However, an empirical model allowing for sharper phase curve variations offers a hint of a flux excess before the occultation, with an amplitude of ~40 ppm, an orbital offset of ~ −30°, and a width of ~20º. We also constrained the orbital eccentricity of WASP-76 b to a value lower than 0.0067, with a 99.7% confidence level. This result contradicts earlier proposed scenarios aimed at explaining the asymmetry observed in high-resolution transit spectroscopy. Conclusions: In light of these findings, we hypothesise that WASP-76 b could have night-side clouds that extend predominantly towards its eastern limb. At this limb, the clouds would be associated with spherical droplets or spherically shaped aerosols of an unknown species, which would be responsible for a glory effect in the visible phase curves.</p