Improvements on analytic modelling of stellar spots

In this work we present the solution of the stellar spot problem using the Kelvin-Stokes theorem. Our result is applicable for any given location and dimension of the spots on the stellar surface. We present explicitely the result up to the second degree in the limb darkening law. This technique can be used to calculate very efficiently mutual photometric effects produced by eclipsing bodies occulting stellar spots and to construct complex spot shapes.Comment: Resubmitted to MNRAS after accounting for minor comments of second review, 9 pages, 5 figures, software available at http://eduscisoft.com/KSINT

Il GIS come strumento di fruizione territoriale e valorizzazione turistica

The goal of this work has been to achieve a Geographic Information System, using innovative cartographic representation of the land and landscape, which can provide to the end users an easier and immediate access regarding tourist, cultural and environmental information. This is an ongoing research, carried out in collaboration with the Department of Civil, Engineering, Environmental, Aerospace, Materials (DICAM) of University of Palermo, with the objective to 548 Atti 17a Conferenza Nazionale ASITA - Riva del Garda 5-7 novembre 2013 achieve a complete integration between software used only by qualified specialists in the field and online platforms display. To experience this work, has been used tourist information about the four regional Sicilian Parks: Madonie, Nebrodi, Etna and Alcantara. The software tools used in this project are the ESRI ArcGIS 9 and Google Earth for the display platform of the virtual globe. For such purpose, the study has been divided into three steps: \uf0b7 First step: gathering maps necessary in order to achieve the objectives and the realization of the thematic maps, either for the environmentally protective restrictions and the territorial administrative boundary. \uf0b7 Second step: research and selection of tourist information for each park; creation and processing of its thematic maps. \uf0b7 Third step: export of thematic maps in Google Earth using KML interchange format, integrated with the addition of metadata containing the characteristics of places. The results obtained to date from this research show that the integration of GIS and online display platforms of satellite images, enriched in geographic content, can be valuable support to the new vision of \u201cdigital tourism\u201d, allowing the use of tourist information to heterogeneous users not necessarily specialized. This study, in the near future, can be extended embracing new environmental contexts and more tourist information

SOAP-T: A tool to study the light-curve and radial velocity of a system with a transiting planet and a rotating spotted star

We present an improved version of SOAP (Boisse et al. 2012) named "SOAP-T", which can generate the radial velocity variations and light-curves for systems consisting of a rotating spotted star with a transiting planet. This tool can be used to study the anomalies inside transit light-curves and the Rossiter-McLaughlin effect, to better constrain the orbital configuration and properties of planetary systems and active zones of their host stars. Tests of the code are presented to illustrate its performance and to validate its capability when compared with analytical models and real data. Finally, we apply SOAP-T to the active star, HAT-P-11, observed by the NASA Kepler space telescope and use this system to discuss the capability of this tool in analyzing light-curves for the cases where the transiting planet overlaps with the star's spots.Comment: 9 pages, 7 figures, accepted for publication in Astronomy and Astrophysic

A hot horizontal branch star with a close K-type main-sequence companion

Dynamical interactions in binary systems are thought to play a major role in the formation of extreme horizontal branch stars (EHBs) in the Galactic field. However, it is still unclear if the same mechanisms are at work in globular clusters, where EHBs are predominantly single stars. Here we report on the discovery of a unique close binary system (period ~1.61 days) in the globular cluster NGC6752, comprising an EHB and a main-sequence companion of 0.63+-0.05 Msun. Such a system has no counterpart among nearly two hundred known EHB binaries in the Galactic field. Its discovery suggests that either field studies are incomplete, missing this type of systems possibly because of selection effects, or that a particular EHB formation mechanism is active in clusters but not in the field

New and updated stellar parameters for 90 transit hosts. The effect of the surface gravity

Context. Precise stellar parameters are crucial in exoplanet research for correctly determining of the planetary parameters. For stars hosting a transiting planet, determining of the planetary mass and radius depends on the stellar mass and radius, which in turn depend on the atmospheric stellar parameters. Different methods can provide different results, which leads to different planet characteristics.}%Spectroscopic surface gravities have shown to be poorly constrained, but the photometry of the transiting planet can provide an independent measurement of the surface gravity. Aims. In this paper, we use a uniform method to spectroscopically derive stellar atmospheric parameters, chemical abundances, stellar masses, and stellar radii for a sample of 90 transit hosts. Surface gravities are also derived photometrically using the stellar density as derived from the light curve. We study the effect of using these different surface gravities on the determination of the chemical abundances and the stellar mass and radius. Methods. A spectroscopic analysis based on Kurucz models in LTE was performed through the MOOG code to derive the atmospheric parameters and the chemical abundances. The photometric surface gravity was determined through isochrone fitting and the use of the stellar density, directly determined from the light curve. Stellar masses and radii are determined through calibration formulae. Results. Spectroscopic and photometric surface gravities differ, but this has very little effect on the precise determination of the stellar mass in our spectroscopic analysis. The stellar radius, and hence the planetary radius, is most affected by the surface gravity discrepancies. For the chemical abundances, the difference is, as expected, only noticable for the abundances derived from analyzing of lines of ionized species.Comment: 12 pages, 6 figures, 5 tables, accepted to A&

Evaluation of symptoms and palatability in healthy volunteers after ingestion of an iced dessert by using different flavours

It is well-known that digestion has a pivotal role in maintaining a state of wellbeing. The influence of certain foods and some herbal drugs has been ascertained. Epidemiological data show that the Mediterranean diet, with a high consumption of fresh vegetables and fruit, mainly citrus, has a beneficial effect and plays a protective gastrointestinal role. Previously, we assessed the influence on the eventual occurrence of symptoms during digestion of an iced dessert containing a mixture of digestive plant extracts, citrus juices and liquors, showing that its ingestion supports and maintains a good digestive process. Taking into consideration that sensory properties of food may also influence digestion, we also evaluated the palatability of the product. In order to evaluate the effect of different tastes on the digestive processes, we performed a further similar evaluation with two new flavours. The ingestion of these iced desserts at the end of the meal does not cause significant gastrointestinal symptoms. Moreover, palatability median score shows a good appreciation of the products. Therefore, the combination of digestive herbs, citrus juice and liquors in different flavours gives rise to a product with a positive mix of good palatability, favourable acceptance and herbal constituents, able to support and maintain a good digestive condition. Copyright © by BIOLIFE, s.a.s

A new analysis of the WASP-3 system: no evidence for an additional companion

In this work we investigate the problem concerning the presence of additional bodies gravitationally bounded with the WASP-3 system. We present eight new transits of this planet and analyse all the photometric and radial velocity data published so far. We did not observe significant periodicities in the Fourier spectrum of the observed minus calculated (O-C) transit timing and radial velocity diagrams (the highest peak having false-alarm probabilities of 56 per cent and 31 per cent, respectively) or long-term trends. Combining all the available information, we conclude that the radial velocity and transit timing techniques exclude, at 99 per cent confidence limit, any perturber more massive than M \gtrsim 100 M_Earth with periods up to 10 times the period of the inner planet. We also investigate the possible presence of an exomoon on this system and determined that considering the scatter of the O-C transit timing residuals a coplanar exomoon would likely produce detectable transits. This hypothesis is however apparently ruled out by observations conducted by other researchers. In case the orbit of the moon is not coplanar the accuracy of our transit timing and transit duration measurements prevents any significant statement. Interestingly, on the basis of our reanalysis of SOPHIE data we noted that WASP-3 passed from a less active (log R'_hk=-4.95) to a more active (log R'_hk=-4.8) state during the 3 yr monitoring period spanned by the observations. Despite no clear spot crossing has been reported for this system, this analysis claims for a more intensive monitoring of the activity level of this star in order to understand its impact on photometric and radial velocity measurements.Comment: MNRAS accepted (14/08/2012