We report the discovery by the HATSouth survey of HATS-6b, an extrasolar planet transiting a V = 15.2 mag, i = 13.7 mag M1V star with a mass of 0.57 M sub(middot in circle) and a radius of 0.57 R ...sub(middot in circle). HATS-6b has a period of P = 3.3253 d, mass of M sub(p) = 0.32 M sub(J) , radius of R sub(p) = 1.00 R sub(J) , and zero-albedo equilibrium temperature of T sub(eq) = 712.8 + or - 5.1 K. HATS-6 is one of the lowest mass stars known to host a close-in gas giant planet, and its transits are among the deepest of any known transiting planet system. We show that from the transit-based stellar density alone it is possible to measure the mass and radius of a ~0.6 M sub(middot in circle) star to ~7 and ~2% precision, respectively.
We report the first disclosure of the planetary nature of Kepler-432 b (aka Kepler object of interest KOI-1299.01). We accurately constrained its mass and eccentricity by high-precision radial ...velocity measurements obtained with the CAFE spectrograph at the CAHA 2.2-m telescope. By simultaneously fitting these new data and Kepler photometry, we found that Kepler-432 b is a dense transiting exoplanet with a mass of Mp = 4.87 ± 0.48MJup and radius of Rp = 1.120 ± 0.036RJup. The planet revolves every 52.5 d around a K giant star that ascends the red giant branch, and it moves on a highly eccentric orbit with e = 0.535 ± 0.030. By analysing two near-IR high-resolution images, we found that a star is located at 1.1′′ from Kepler-432, but it is too faint to cause significant effects on the transit depth. Together with Kepler-56 and Kepler-91, Kepler-432 occupies an almost-desert region of parameter space, which is important for constraining the evolutionary processes of planetary systems.
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We announce the discovery of K2-139 b (EPIC 218916923 b), a transiting warm-Jupiter (Teq = 547 ± 25 K) on a 29-d orbit around an active (log R'_HK = -4.46 ± 0.06) K0V star in K2 Campaign 7. We derive ...the system's parameters by combining the K2 photometry with ground-based follow-up observations. With a mass of 0.387_-0.075^+0.083 M_J and radius of 0.808_-0.033^+0.034 R_J, K2-139 b is one of the transiting warm Jupiters with the lowest mass known to date. The planetary mean density of 0.91_-0.20^+0.24 g/cm^3 can be explained with a core of ~50 M⊕. Given the brightness of the host star (V = 11.653 mag), the relatively short transit duration (~5 h), and the expected amplitude of the Rossiter-McLaughlin effect (~25m/s), K2-139 is an ideal target to measure the spin-orbit angle of a planetary system hosting a warm Jupiter.
We present 17 transit light curves of the ultrashort period planetary system WASP-103, a strong candidate for the detection of tidally-induced orbital decay. We use these to establish a ...high-precision reference epoch for transit timing studies. The time of the reference transit mid-point is now measured to an accuracy of 4.8 s, versus 67.4 s in the discovery paper, aiding future searches for orbital decay. With the help of published spectroscopic measurements and theoretical stellar models, we determine the physical properties of the system to high precision and present a detailed error budget for these calculations. The planet has a Roche lobe filling factor of 0.58, leading to a significant asphericity; we correct its measured mass and mean density for this phenomenon. A high-resolution Lucky Imaging observation shows no evidence for faint stars close enough to contaminate the point spread function of WASP-103. Our data were obtained in the Bessell RI and the SDSS griz passbands and yield a larger planet radius at bluer optical wavelengths, to a confidence level of 7.3σ. Interpreting this as an effect of Rayleigh scattering in the planetary atmosphere leads to a measurement of the planetary mass which is too small by a factor of 5, implying that Rayleigh scattering is not the main cause of the variation of radius with wavelength.
We present 17 high-precision light curves of five transits of the planet Qatar-2 b, obtained from four defocused 2 m-class telescopes. Three of the transits were observed simultaneously in the Sloan ...g
′
r
′
i
′
z
′ passbands using the seven-beam Gamma Ray Burst Optical and Near-Infrared Detector imager on the MPG/ESO 2.2-m telescope. A fourth was observed simultaneously in Gunn grz using the Centro Astronómico Hispano Alemán 2.2-m telescope with Bonn University Simultaneous Camera, and in r using the Cassini 1.52-m telescope. Every light curve shows small anomalies due to the passage of the planetary shadow over a cool spot on the surface of the host star. We fit the light curves with the prism+gemc model to obtain the photometric parameters of the system and the position, size and contrast of each spot. We use these photometric parameters and published spectroscopic measurements to obtain the physical properties of the system to high precision, finding a larger radius and lower density for both star and planet than previously thought. By tracking the change in position of one star-spot between two transit observations, we measure the orbital obliquity of Qatar-2 b to be λ = 4
$_{.}^{\circ}$
3 ± 4
$_{.}^{\circ}$
5, strongly indicating an alignment of the stellar spin with the orbit of the planet. We calculate the rotation period and velocity of the cool host star to be 11.5 ± 0.2 d and 3.28 ± 0.04 km s−1 at a colatitude of 74°. We assemble the planet's transmission spectrum over the 386–976 nm wavelength range and search for variations of the measured radius of Qatar-2 b as a function of wavelength. Our analysis highlights a possible H2/He Rayleigh scattering in the blue.
We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54-m telescope at European Southern Obseratory La Silla. In order to ...minimize both random and flat-fielding errors, we defocused the telescope so its point spread function approximated an annulus of diameter 40 pixel (16 arcsec). Data reduction was undertaken using standard aperture photometry plus an algorithm for optimally combining the ensemble of comparison stars. The resulting light curves have point-to-point scatters of 0.50 mmag for the first transit and 0.59 mmag for the second. We construct detailed signal-to-noise ratio calculations for defocused photometry, and apply them to our observations. We model the light curves with the jktebop code and combine the results with tabulated predictions from theoretical stellar evolutionary models to derive the physical properties of the WASP-5 system. We find that the planet has a mass of Mb= 1.637 ± 0.075 ± 0.033 MJup, a radius of Rb= 1.171 ± 0.056 ± 0.012 R Jup, a large surface gravity of gb= 29.6 ± 2.8 m s−2 and a density of ρb= 1.02 ± 0.14 ± 0.01 ρJup (statistical and systematic uncertainties). The planet's high equilibrium temperature of Teq= 1732 ± 80 K makes it a good candidate for detecting secondary eclipses.
In this preliminary study, a digestive method used in forensic context to extract diatoms has been applied in organs taken from ten wildlife animals belonging three species of mammals (a deer, a roe ...and five otters) and one species of birds (two magpies). Only four carcasses were recovered from aquatic environments (bath trough for animals, bathtub irrigation, river) and only in three cases out of ten that the cause of death was ruled out as drowning. In seven cases, the death was due to other causes: gunshot injuries for one otter, blunt trauma for a magpie, and traumatic injuries followed by motor vehicle collision in other four otters and a roe. Post-mortem examination was performed in all carcasses. The diatom test protocol was performed according to the Italian guidelines for analysis of benthic diatoms for ecological status assessment of inland waters. Five grams of lung, liver, and kidney was taken from all the animal carcasses. In some cases, additional tissue samples were also available among which brain, heart, spleen, and bone marrow. In all four cases found in water, the drowning medium was also available. Hydrogen peroxide (H
2
O
2
) digestion was performed, and identification of 21 genera of diatoms was obtained. The method proved to be suitable for the identification of diatoms in the organs of the animals drowned supporting the final diagnosis of drowning. Only in otters, all died for causes other than drowning, diatoms did not prove to be suitable for the diagnosis of drowning since their presence in the internal organs was mainly related to their main diet based on fishmeal. The authors believe that this first trial is very promising, and the results suggest that diatom test can be easily applied in forensic veterinary context.
Optical properties of GaN nanowires (NWs) grown on chemical vapor deposited-graphene transferred on an amorphous support are reported. The growth temperature was optimized to achieve a high NW ...density with a perfect selectivity with respect to a SiO2 surface. The growth temperature window was found to be rather narrow (815°C 5°C). Steady-state and time-resolved photoluminescence from GaN NWs grown on graphene was compared with the results for GaN NWs grown on conventional substrates within the same molecular beam epitaxy reactor showing a comparable optical quality for different substrates. Growth at temperatures above 820 °C led to a strong NW density reduction accompanied with a diameter narrowing. This morphology change leads to a spectral blueshift of the donor-bound exciton emission line due to either surface stress or dielectric confinement. Graphene multi-layered micro-domains were explored as a way to arrange GaN NWs in a hollow hexagonal pattern. The NWs grown on these domains show a luminescence spectral linewidth as low as 0.28 meV (close to the set-up resolution limit).
We report the discovery of four transiting F-M binary systems with companions between 0.1 and 0.2 M in mass by the HATSouth survey. These systems have been characterized via a global analysis of the ...HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters and equating spectroscopic primary star rotation velocity with spin-orbit synchronization. These new very low mass companions are HATS550-016B (
,
), HATS551-019B (
,
), HATS551-021B (
,
) and HATS553-001B (
,
). We examine our sample in the context of the radius anomaly for fully convective low-mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5 per cent systematic deviation between the measured radii and theoretical isochrone models.
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