Jupiter as an exoplanet: UV to NIR transmission spectrum reveals hazes, a Na layer and possibly stratospheric H2O-ice clouds

Currently, the analysis of transmission spectra is the most successful technique to probe the chemical composition of exoplanet atmospheres. But the accuracy of these measurements is constrained by observational limitations and the diversity of possible atmospheric compositions. Here we show the UV-VIS-IR transmission spectrum of Jupiter, as if it were a transiting exoplanet, obtained by observing one of its satellites, Ganymede, while passing through Jupiter's shadow i.e., during a solar eclipse from Ganymede. The spectrum shows strong extinction due to the presence of clouds (aerosols) and haze in the atmosphere, and strong absorption features from CH4. More interestingly, the comparison with radiative transfer models reveals a spectral signature, which we attribute here to a Jupiter stratospheric layer of crystalline H2O ice. The atomic transitions of Na are also present. These results are relevant for the modeling and interpretation of giant transiting exoplanets. They also open a new technique to explore the atmospheric composition of the upper layers of Jupiter's atmosphere.Comment: Accepted for publication in ApJ Letter

Qatar Exoplanet Survey: Qatar-8b, 9b, and 10b—A Hot Saturn and Two Hot Jupiters

In this paper we present three new extrasolar planets from the Qatar Exoplanet Survey. Qatar-8b is a hot Saturn, with M P = 0.37 M J and R P = 1.3 R J, orbiting a solar- like star every P orb = 3.7 days. Qatar-9b is a hot Jupiter with a mass of M P = 1.2 M J and a radius of R P = 1 R J, in an orbit of P orb = 1.5 days around a low mass, M ⋆ = 0.7 M ☉, mid-K main- sequence star. Finally, Qatar-10b is a hot, T eq ∼ 2000 K, sub-Jupiter mass planet, M P = 0.7 M J, with a radius of R P = 1.54 R J and an orbital period of P orb = 1.6 days, placing it on the edge of the sub-Jupiter desert

Discovery of XO-6b: A Hot Jupiter Transiting a Fast Rotating F5 Star on an Oblique Orbit

© 2017. The American Astronomical Society. All rights reserved.Only a few hot Jupiters are known to orbit around fast rotating stars. These exoplanets are harder to detect and characterize and may be less common than around slow rotators. Here, we report the discovery of the transiting hot Jupiter XO-6b, which orbits a bright, hot, and fast rotating star: V = 10.25, T effsstarf = 6720 ± 100 K, v sin i sstarf = 48 ± 3 km s-1. We detected the planet from its transits using the XO instruments and conducted a follow-up campaign. Because of the fast stellar rotation, radial velocities taken along the orbit do not yield the planet's mass with a high confidence level, but we secure a 3s upper limit M p < 4.4 M Jup. We also obtain high-resolution spectroscopic observations of the transit with the SOPHIE spectrograph at the 193-cm telescope of the Observatoire de Haute-Provence and analyze the stellar lines profile by Doppler tomography. The transit is clearly detected in the spectra. The radii measured independently from the tomographic analysis and from the photometric light curves are consistent, showing that the object detected by both methods is the same and indeed transits in front of XO-6. We find that XO-6b lies on a prograde and misaligned orbit with a sky-projected obliquity {\boldsymbol{\lambda }}=-20\buildrel{\circ}\over{.} 7\pm 2\buildrel{\circ}\over{.} 3. The rotation period of the star is shorter than the orbital period of the planet: P rot < 2.12 days, P orb = 3.77 days. Thus, this system stands in a largely unexplored regime of dynamical interactions between close-in giant planets and their host stars.Peer Reviewe

HD 89345: a bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding the mass and radius to be 1.12^{+0.04}_{-0.01} M_☉ and 1.657^{+0.020}_{-0.004} R_☉, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4^{+0.4}_{-1.3} Gyr, and the non-detection of mixed modes. The star hosts a `warm Saturn' (P = 11.8 d, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e ≈ 0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub- Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity

K2-260 b: a hot Jupiter transiting an F star, and K2-261 b: a warm Saturn around a bright G star

We present the discovery and confirmation of two new transiting giant planets from the Kepler extended mission K2. K2-260 b is a hot Jupiter transiting a V = 12.7 F6V star in K2 Field 13, with a mass and radius of M⋆ = 1.39_{-0.06}^{+0.05} M_{☉} and R⋆ = 1.69 ± 0.03 R_{☉}. The planet has an orbital period of P = 2.627 d, and a mass and radius of M_P=1.42^{+0.31}_{-0.32} M_J and R_P=1.552^{+0.048}_{-0.057} R_J. This is the first K2 hot Jupiter with a detected secondary eclipse in the Kepler bandpass, with a depth of 71 ± 15 ppm, which we use to estimate a geometric albedo of Ag ̃ 0.2. We also detected a candidate stellar companion at 0.6 arcsec from K2-260; we find that it is very likely physically associated with the system, in which case it would be an M5-6V star at a projected separation of ̃400 au. K2-261 b is a warm Saturn transiting a bright (V = 10.5) G7IV/V star in K2 Field 14. The host star is a metal rich ([Fe/H] = 0.36 ± 0.06), mildly evolved 1.10_{-0.02}^{+0.01} M_{☉} star with R⋆ = 1.65 ± 0.04 R_{☉}. Thanks to its location near the main-sequence turn-off, we can measure a relatively precise age of 8.8_{-0.3}^{+0.4} Gyr. The planet has P = 11.633 d, MP = 0.223 ± 0.031 M_J, and R_P=0.850^{+0.026}_{-0.022} R_J, and its orbit is eccentric (e=0.39 ± 0.15). Its brightness and relatively large transit depth make this one of the best-known warm Saturns for follow-up observations to further characterize the planetary system

APOE epsilon4 and Alzheimer's disease: positive association in a Colombian clinical series and review of the Latin-American studies Asociación positiva entre APOE épsilon4 y demencia de Alzheimer en una serie clinica en Bogotá (Colombia) y revision de los estudios latinoamericanos

OBJECTIVE: As the strength of the association between the APOE epsilon4 allele and Alzheimer's disease (AD) varies across ethnic groups, we studied if there was such an association in Colombian patients. METHOD: We performed apolipoprotein E (APOE) genotyping in a clinical sample of 83 unrelated AD patients, predominantly late-onset (>65 yrs) including familial ( n =30) and sporadic AD cases (n= 53) diagnosed according to NINCDS-ADRDA criteria and assessed by a multi-disciplinary team. Control subjects (n = 44) had no significant cognitive impairment by medical interview and neuro-psychological testing. RESULTS: We found a high association (OR= 5.1 95%CI 1.9 -13.6) between APOE epsilon4 and AD, in this series with predominantly late-onset cases with familial aggregation in 24 cases (28.9%). A significant negative association was found between epsilon2 and AD (OR= 0.2 95% CI 0.05-0.75). CONCLUSION: Further population-based surveys in Colombia are warranted to precise a possible dose effect of APOE epsilon4.<br>OBJETIVO: Como la fortaleza de la asociación entre el alelo épsilon4 del gen APOE y la enfermedad de Alzheimer (EA) difiere entre grupos étnicos, quisimos evaluar si esta asociación existe en pacientes colombianos. MÉTODOS: Realizamos una genotipificación para el gen de la apolipoproteina E (APOE) en una muestra clínica de 83 pacientes con EA no relacionados, de inicio predominantemente tardío (> 65 años), incluyendo casos familiares (n=30) y esporádicos (n=53) diagnosticados según los criterios del NINCDS-ADRDA y evaluados por un equipo multi-disciplinario. Los sujetos control (n= 44) no presentaban deterioro cognoscitivo de acuerdo con la entrevista médica y la evaluación neuropsicológica. RESULTADOS: Hallamos una alta asociación (OR= 5.1; IC95% 1.9- 13.6) entre APOE épsilon4 y EA en la serie de casos de inicio tardío y con agregación familiar en 24 sujetos (28.9%). Una asociación negativa, estadísticamente significativa, fue encontrada entre épsilon2 y EA (OR= 0.2; IC95% 0.05-0.75). CONCLUSIÓN: En Colombia son necesarios futuros estudios con base poblacional para poder precisar la existencia o no de un efecto de dosis de APOE épsilon4