The Mass of Kepler-93b and The Composition of Terrestrial Planets

Kepler-93b is a 1.478 ± 0.019 R ⊕ planet with a4.7 day period around a bright (V = 10.2), astroseismicallycharacterized host star with a mass of 0.911 ± 0.033 M⊙ and a radius of 0.919 ± 0.011 R⊙. Based on 86 radial velocity observations obtainedwith the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32archival Keck/HIRES observations, we present a precise mass estimate of4.02 ± 0.68 M ⊕. The corresponding high densityof 6.88 ± 1.18 g cm-3 is consistent with a rockycomposition of primarily iron and magnesium silicate. We compareKepler-93b to other dense planets with well-constrained parameters andfind that between 1 and 6 M ⊕, all dense planetsincluding the Earth and Venus are well-described by the same fixed ratioof iron to magnesium silicate. There are as of yet no examples of suchplanets with masses >6 M ⊕. All known planets inthis mass regime have lower densities requiring significant fractions ofvolatiles or H/He gas. We also constrain the mass and period of theouter companion in the Kepler-93 system from the long-term radialvelocity trend and archival adaptive optics images. As the sample ofdense planets with well-constrained masses and radii continues to grow,we will be able to test whether the fixed compositional model found forthe seven dense planets considered in this paper extends to the fullpopulation of 1-6 M ⊕ planets.Based on observations made with the Italian Telescopio Nazionale Galileo(TNG) operated on the island of La Palma by the Fundación GalileoGalilei of the INAF (Istituto Nazionale di Astrofisica) at the SpanishObservatorio del Roque de los Muchachos of the Instituto de Astrofisicade Canarias.

A Gap with a Deficit of Large Grains in the Protoplanetary Disk around TW Hya

We report 3 au resolution imaging observations of the protoplanetary disk aroundTW Hya at 145 and 233 GHz with the Atacama Large Millimeter/Submillimeter Array.Our observations revealed two deep gaps (~25-50 %) at 22 and 37 au and shallowergaps (a few %) at 6, 28, and 44 au, as recently reported by Andrews et al. (2016). Thecentral hole with a radius of  3 au was also marginally resolved. The most remarkablefinding is that the spectral index α(R) between bands 4 and 6 peaks at the 22 au gap.The derived power-law index of the dust opacity β(R) is  ~1.7 at the 22 au gap anddecreases toward the disk center to ~0. The most prominent gap at 22 au could becaused by the gravitational interaction between the disk and an unseen planet with amass of ≲1.5 MNeptune although other origins may be possible. The planet-induced gap is supported by the fact that β(R) is enhanced at the 22 au gap, indicating a deficitof mm-sized grains within the gap due to dust filtration by a planet.

Alteration of cell-wall porosity is involved in osmotic stress-induced enhancement of aluminium resistance in common bean (Phaseolus vulgaris L.)

Aluminium (Al) toxicity and drought are the two major abiotic stress factors limiting common bean production in the tropics. Using hydroponics, the short-term effects of combined Al toxicity and drought stress on root growth and Al uptake into the root apex were investigated. In the presence of Al stress, PEG 6000 (polyethylene glycol)-induced osmotic (drought) stress led to the amelioration of Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1. PEG 6000 (>> PEG 1000) treatment greatly decreased Al accumulation in the 1 cm root apices even when the roots were physically separated from the PEG solution using dialysis membrane tubes. Upon removal of PEG from the treatment solution, the root tips recovered from osmotic stress and the Al accumulation capacity was quickly restored. The PEG-induced reduction of Al accumulation was not due to a lower phytotoxic Al concentration in the treatment solution, reduced negativity of the root apoplast, or to enhanced citrate exudation. Also cell-wall (CW) material isolated from PEG-treated roots showed a low Al-binding capacity which, however, was restored after destroying the physical structure of the CW. The comparison of the Al(3+), La(3+), Sr(2+), and Rb(+) binding capacity of the intact root tips and the isolated CW revealed the specificity of the PEG 6000 effect for Al. This could be due to the higher hydrated ionic radius of Al(3+) compared with other cations (Al(3+) >> La(3+) > Sr(2+) > Rb(+)). In conclusion, the results provide circumstantial evidence that the osmotic stress-inhibited Al accumulation in root apices and thus reduced Al-induced inhibition of root elongation in the Al-sensitive genotype VAX 1 is related to the alteration of CW porosity resulting from PEG 6000-induced dehydration of the root apoplast.

Release currents of IP₃ receptor channel clusters and concentration profiles

We simulate currents and concentration profiles generated by Ca2+ release from the endoplasmic reticulum (ER) to the cytosol through IP3 receptor channel clusters. Clusters are described as conducting pores in the lumenal membrane with a diameter from 6 nm to 36 nm. The endoplasmic reticulum is modeled as a disc with a radius of 1–12 mm and an inner height of 28 nm. We adapt the dependence of the currents on the trans Ca2+ concentration (intralumenal) measured in lipid bilayer experiments to the cellular geometry. Simulated currents are compared with signal mass measurements in Xenopus oocytes. We find that release currents depend linearly on the concentration of free Ca2+ in the lumen. The release current is approximately proportional to the square root of the number of open channels in a cluster. Cytosolic concentrations at the location of the cluster range from 25 μM to 170 μM. Concentration increase due to puffs in a distance of a few micrometers from the puff site is found to be in the nanomolar range. Release currents decay biexponentially with timescales of < 1 s and a few seconds. Concentration profiles decay with timescales of 0.125–0.250 s upon termination of release.

SEDIMENT BIOTURBATION POTENTIAL of UCA RAPAX and UCA URUGUAYENSIS AS A RESULT of THEIR FEEDING ACTIVITY

Bioturbation of mangrove sediments by Uca uruguayensis (Nobili, 1901) and U. rapax (Smith, 1870) was compared based on the grain-size composition and organic content in surface sediment around the burrow and feeding pellets in two mangrove zones of the Sao Vicente Estuary, state of São Paulo, Brazil. For each species, 25 burrows with active crabs were selected. All pellets within a 15-cm radius of each burrow were carefully collected; samples of substrate were taken; and the crab occupant was excavated, sexed, and measured for carapace width (CW). The number of spoon-tipped setae on the second maxilliped of each species was estimated; U. uruguayensis showed more of these setae than U. rapax. For both species, the sediment post-processed by feeding activity (feeding pellets) showed a similar increase of coarser fractions and a smaller organic content. However. U. uruguayensis was more efficient in removing organic matter (88.1%) from the sediment than U. rapax (37.5%). These results suggest that different numbers of spoon-tipped setae on the second maxillipeds of the fiddler crabs do not affect the potential for grain-size selection, but result in differing abilities to remove organic matter from the sediment.

Modeling and analysis of thermoelectric energy conversion efficiency in nanostructures.

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Sub-kiloparsec alma imaging of compact star-forming galaxies at z ~ 2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies

We present spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) 870 μm dust continuum maps of six massive, compact, dusty star-forming galaxies at z ~ 2.5. These galaxies are selected for their small rest-frame optical sizes (r_e,F160W ~ 1.6 kpc) and high stellar mass densities that suggest that they are direct progenitors of compact quiescent galaxies at z ~ 2. The deep observations yield high far-infrared (FIR) luminosities of L_IR = 10^12.3-12.8 L_⨀ and star formation rates (SFRs) of SFR = 200–700 M_⊙ yr^−1, consistent with those of typical star-forming "main sequence" galaxies. The high spatial resolution (FWHM ~ 0 12–0 18) ALMA and Hubble Space Telescope photometry are combined to construct deconvolved, mean radial profiles of their stellar mass and (UV+IR) SFR. We find that the dusty, nuclear IR–SFR overwhelmingly dominates the bolometric SFR up to r ~ 5 kpc, by a factor of over 100× from the unobscured UV–SFR. Furthermore, the effective radius of the mean SFR profile (r_e,SFR ~ 1 kpc) is ~30% smaller than that of the stellar mass profile. The implied structural evolution, if such nuclear starburst last for the estimated gas depletion time of Δt = ±100 Myr, is a 4×increase of the stellar mass density within the central 1 kpc and a 1.6× decrease of the half-mass–radius. This structural evolution fully supports dissipation-driven, formation scenarios in which strong nuclear starbursts transform larger, star-forming progenitors into compact quiescent galaxies.

Estimation of Convective Extreme Events over Germany based on Large Scale Parameters

Strong convective events can produce extreme precipitation, hail, lightning or gusts, potentially inducing severe socio-economic impacts. These events have a relatively small spatial extension and, in most cases, a short lifetime. In this study, a model is developed for estimating convective extreme events based on large scale conditions. It is shown that strong convective events can be characterized by a Weibull distribution of radar-based rainfall with a low shape and high scale parameter value. A radius of 90km around a station reporting a convective situation turned out to be suitable. A methodology is developed to estimate the Weibull parameters and thus the occurrence probability of convective events from large scale atmospheric instability and enhanced near-surface humidity, which are usually found on a larger scale than the convective event itself. Here, the probability for the occurrence of extreme convective events is estimated from the KO-index indicating the stability, and relative humidity at 1000hPa. Both variables are computed from ERA-Interim reanalysis. In a first version of the methodology, these two variables are applied to estimate the spatial rainfall distribution and to estimate the occurrence of a convective event. The developed method shows significant skill in estimating the occurrence of convective events as observed at synoptic stations, lightning measurements, and severe weather reports. In order to take frontal influences into account, a scheme for the detection of atmospheric fronts is implemented. While generally higher instability is found in the vicinity of fronts, the skill of this approach is largely unchanged. Additional improvements were achieved by a bias-correction and the use of ERA-Interim precipitation. The resulting estimation method is applied to the ERA-Interim period (1979-2014) to establish a ranking of estimated convective extreme events. Two strong estimated events that reveal a frontal influence are analysed in detail. As a second application, the method is applied to GCM-based decadal predictions in the period 1979-2014, which were initialized every year. It is shown that decadal predictive skill for convective event frequencies over Germany is found for the first 3-4 years after the initialization.

The FAMU experiment: characterization of innovative detectors for high precision spectroscopy

The incompatibility between the proton radius values measured in recent years has given rise to what is now called the proton radius puzzle. This discrepancy is nowadays without explanation. In order to find a solution to the proton radius puzzle a new experiment has been proposed. The aim of this experiment, called FAMU, is to obtain a new and more precise measure of the Zemach radius of the proton, ie the quantity that has the highest uncertainty in high precision spectroscopy. If this measurement confirmed the results obtained before 2010, the starting date of the puzzle, then the discrepancy would be caused by procedural errors or ignored corrections. Otherwise, the new value would indicate the presence of new physics still unkown.

Aplicação de indentação instrumentada na caracterização mecânica de poliuretana derivada de óleo de mamona

Neste trabalho são investigadas as propriedades mecânicas de poliuretana derivada do óleo de mamona, utilizando a técnica de indentação instrumentada com penetradores de geometrias piramidal e esférica. Foi analisada a influência da forma do penetrador utilizado nos ensaios de indentação instrumentada para se obter valores das propriedades mecânicas de polímero derivado de óleo de mamona. Os penetradores utilizados são de pontas piramidais dos tipos Berkovich e canto de cubo e esférico de raio igual a 150 μm em um Nanoindenter XP TM com cargas aplicadas entre 1 e 200 mN. As penetrações variam de acordo com o formato do penetrador, sendo maiores para pontas agudas. A dureza e o módulo de elasticidade foram determinados, utilizando o método de Oliver e Pharr. Verificou-se que os valores medidos para a dureza são maiores para penetradores mais agudos. Os valores obtidos com a ponta piramidal Berkovich foram de 0,14 GPa para pequenas penetrações e 0,12 GPa para maiores penetrações. Já os valores obtidos com ponta canto de cubo foram 25 a 30% maiores. Isso está relacionado com os volumes das regiões que apresentam deformações plásticas elevadas, no caso de penetradores agudos comparados com os volumes das regiões que sofrem deformações viscoelásticas. A viscosidade aparente determinada, utilizando penetrador esférico em testes de força aplicada constante, é igual a (22 ± 2) × 10(12) Pa.s.

An accurate distance to 2M1207Ab

Context. In April 2004, the first image was obtained of a planetary mass companion (now known as 2M 1207 b) in orbit around a self-luminous object different from our own Sun (the young brown dwarf 2MASSW J 1207334-393254, hereafter 2M 1207 A). That 2M 1207 b probably formed via fragmentation and gravitational collapse offered proof that such a mechanism can form bodies in the planetary mass regime. However, the predicted mass, luminosity, and radius of 2MI207 b depend on its age, distance, and other observables, such as effective temperature. Aims. To refine our knowledge of the physical properties of 2M 1207 b and its nature, we accurately determined the distance to the 2M 1207 A and b system by measuring of its trigonometric parallax at the milliarcsec level. Methods. With the ESO NTT/SUS12 telescope, we began a campaign of photometric and astrometric observations in 2006 to measure the trigonometric parallax of 2M 1207 A. Results. An accurate distance (52.4 +/- 1.1 pc) to 2M1207A was measured. From distance and proper motions we derived spatial velocities that are fully compatible with TWA membership. Conclusions. With this new distance estimate, we discuss three scenarios regarding the nature of 2M 1207 b: (1) a cool (1150 +/- 150 K) companion of mass 4 +/- 1 M-Jup (2) a warmer (1600 +/- 100 K) and heavier (8 +/- 2 M-Jup) companion occulted by an edge-on circumsecondary disk, or (3) a hot protoplanet collision afterglow.

Transiting exoplanets from the CoRoT space mission XV. CoRoT-15b: a brown-dwarf transiting companion

We report the discovery by the CoRoT space mission of a transiting brown dwarf orbiting a F7V star with an orbital period of 3.06 days. CoRoT-15b has a radius of 1.12(-0.15)(+0.30) R(Jup) and a mass of 63.3 +/- 4.1 M(Jup), and is thus the second transiting companion lying in the theoretical mass domain of brown dwarfs. CoRoT-15b is either very young or inflated compared to standard evolution models, a situation similar to that of M-dwarf stars orbiting close to solar-type stars. Spectroscopic constraints and an analysis of the lightcurve imply a spin period in the range 2.9-3.1 days for the central star, which is compatible with a double-synchronisation of the system.

Transiting exoplanets from the CoRoT space mission X. CoRoT-10b: a giant planet in a 13.24 day eccentric orbit

Context. The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view. Aims. We report the discovery of CoRoT-10b, a giant planet on a highly eccentric orbit (e = 0.53 +/- 0.04) revolving in 13.24 days around a faint (V = 15.22) metal-rich K1V star. Methods. We used CoRoT photometry, radial velocity observations taken with the HARPS spectrograph, and UVES spectra of the parent star to derive the orbital, stellar, and planetary parameters. Results. We derive a radius of the planet of 0.97 +/- 0.07 R(Jup) and a mass of 2.75 +/- 0.16 M(Jup). The bulk density,rho(p) = 3.70 +/- 0.83 g cm(-3), is similar to 2.8 that of Jupiter. The core of CoRoT-10b could contain up to 240 M(circle plus) of heavy elements. Moving along its eccentric orbit, the planet experiences a 10.6-fold variation in insolation. Owing to the long circularisation time, tau(circ) > 7 Gyr, a resonant perturber is not required to excite and maintain the high eccentricity of CoRoT-10b.

Transiting exoplanets from the CoRoT space mission XI. CoRoT-8b: a hot and dense sub-Saturn around a K1 dwarf

Aims. We report the discovery of CoRoT-8b, a dense small Saturn-class exoplanet that orbits a K1 dwarf in 6.2 days, and we derive its orbital parameters, mass, and radius. Methods. We analyzed two complementary data sets: the photometric transit curve of CoRoT-8b as measured by CoRoT and the radial velocity curve of CoRoT-8 as measured by the HARPS spectrometer**. Results. We find that CoRoT-8b is on a circular orbit with a semi-major axis of 0.063 +/- 0.001 AU. It has a radius of 0.57 +/- 0.02 R(J), a mass of 0.22 +/- 0.03 M(J), and therefore a mean density of 1.6 +/- 0.1 g cm(-3). Conclusions. With 67% of the size of Saturn and 72% of its mass, CoRoT-8b has a density comparable to that of Neptune (1.76 g cm(-3)). We estimate its content in heavy elements to be 47-63 M(circle plus), and the mass of its hydrogen-helium envelope to be 7-23 M(circle plus). At 0.063 AU, the thermal loss of hydrogen of CoRoT-8b should be no more than similar to 0.1% over an assumed integrated lifetime of 3 Ga.

Transiting exoplanets from the CoRoT space mission XII. CoRoT-12b: a short-period low-density planet transiting a solar analog star

We report the discovery by the CoRoT satellite of a new transiting giant planet in a 2.83 days orbit about a V = 15.5 solar analog star (M(*) = 1.08 +/- 0.08 M(circle dot), R(*) = 1.1 +/- 0.1 R(circle dot), T(eff) = 5675 +/- 80 K). This new planet, CoRoT-12b, has a mass of 0.92 +/- 0.07 M(Jup) and a radius of 1.44 +/- 0.13 R(Jup). Its low density can be explained by standard models for irradiated planets.