A purely geometric distance to the binary star Atlas, a member of the Pleiades

We present radial velocity and new interferometric measurements of the double star Atlas, which permit, with the addition of published interferometric data, to precisely derive the orbital parameters of the binary system and the masses of the components. The derived semi-major axis, compared with its measured angular size, allows to determine a distance to Atlas of 132+-4 pc in a purely geometrical way. Under the assumption that the location of Atlas is representative of the average distance of the cluster, we confirm the distance value generally obtained through main sequence fitting, in contradiction with the early Hipparcos result (118.3+-3.5 pc).Comment: 5 pages, 3 figures, accepted for publication in A&A Letter

Extrasolar planets and brown dwarfs around A-F type stars. II. A planet found with ELODIE around the F6V star HD 33564

We present here the detection of a planet orbiting around the F6V star HD 33564. The radial velocity measurements, obtained with the ELODIE echelle spectrograph at the Haute-Provence Observatory, show a variation with a period of 388 days. Assuming a primary mass of 1.25 Mo, the best Keplerian fit to the data leads to a minimum mass of 9.1 MJup for the companion.Comment: 5 pages. Final version, accepted for publication (A&A). Some Spitzer results on HD33564 (taken this year; not yet published), finally show that the detection of IR excess around this star (by IRAS) is spuriou

Understanding the impact of diet and nutrition on symptoms of Tourette Syndrome: A Scoping Review

This document is the accepted manuscript version. The final, definitive version of this paper has been published in Journal of Child Health Care, December 2017, published by SAGE Publishing, doi:https://doi.org/10.1177/1367493517748373.Anecdotal reports frequently suggest some dietary involvement in the maintenance of tics in children with Tourette syndrome (TS). This scoping review aimed to (1) understand the possible influence of diet as a trigger of tics and (2) map out the existing studies documenting dietary interventions in children with TS. Current evidence suggests no single diet to benefit individuals with TS. However, reports from parents of children with TS suggest that certain allergens in food may exacerbate tic-related symptoms. For example, an increase in tics has been related to the consumption of caffeine and refined sugar. Moreover, oligoantigenic diets and sugar-free diets have been identified as significantly reducing tics. More research is urgently needed to develop more accurate guidance for parents and children with TS, as many have reported using dietary and nutritional supplements, despite the lack of evidence detailing any benefits, side effects and recommended doses.Peer reviewedFinal Accepted Versio

Extrasolar planets and brown dwarfs around A--F type stars. VIII. A giant planet orbiting the young star HD113337

In the frame of the search for extrasolar planets and brown dwarfs around early-type main-sequence stars, we present the detection of a giant planet around the young F-type star HD113337. We estimated the age of the system to be 150 +100/-50 Myr. Interestingly, an IR excess attributed to a cold debris disk was previously detected on this star. The SOPHIE spectrograph on the 1.93m telescope at Observatoire de Haute-Provence was used to obtain ~300 spectra over 6 years. We used our SAFIR tool, dedicated to the spectra analysis of A and F stars, to derive the radial velocity variations. The data reveal a 324.0 +1.7/-3.3 days period that we attribute to a giant planet with a minimum mass of 2.83 +- 0.24 Mjup in an eccentric orbit with e=0.46 +- 0.04. A long-term quadratic drift, that we assign to be probably of stellar origin, is superimposed to the Keplerian solution.Comment: 7 pages, 4 figure

Deep infrared imaging of close companions to austral A- and F-type stars

The search for substellar companions around stars with different masses along the main sequence is critical to understand the different processes leading to the formation of low-mass stars, brown dwarfs, and planets. In particular, the existence of a large population of low-mass stars and brown dwarfs physically bound to early-type main-sequence stars could imply that the massive planets recently imaged at wide separations (10-100 AU) around A-type stars are disc-born objects in the low-mass tail of the binary distribution. Our aim is to characterize the environment of early-type main-sequence stars by detecting brown dwarf or low-mass star companions between 10 and 500 AU. High contrast and high angular resolution near-infrared images of a sample of 38 southern A- and F-type stars have been obtained between 2005 and 2009 with the instruments VLT/NaCo and CFHT/PUEO. Multi-epoch observations were performed to discriminate comoving companions from background contaminants. About 41 companion candidates were imaged around 23 stars. Follow-up observations for 83% of these stars allowed us to identify a large number of background contaminants. We report the detection of 7 low-mass stars with masses between 0.1 and 0.8 Msun in 6 multiple systems: the discovery of a M2 companion around the A5V star HD14943 and the detection of the B component of the F4V star HD41742 quadruple system; we resolve the known companion of the F6.5V star HD49095 as a short-period binary system composed by 2 M/L dwarfs. We also resolve the companions to the astrometric binaries iot Crt (F6.5V) and 26 Oph (F3V), and identify a M3/M4 companion to the F4V star omi Gru, associated with a X-ray source. The global multiplicity fraction measured in our sample of A and F stars is >16%. A parallel velocimetric survey of our stars let us conclude that the imaged companions can impact on the observed radial velocity measurements.Comment: 21 pages, 12 figures, 7 tables. Accepted for publication in Astronomy and Astrophysics. The full version of the preprint including the appendices (24 pages of figures), can be retrieved at http://www-laog.obs.ujf-grenoble.fr/~dehrenre/articles/afsurvey

Refined parameters and spectroscopic transit of the super-massive planet HD147506b

In this paper, we report a refined determination of the orbital parameters and the detection of the Rossiter-McLaughlin effect of the recently discovered transiting exoplanet HD147506b (HAT-P-2b). The large orbital eccentricity at the short orbital period of this exoplanet is unexpected and is distinguishing from other known transiting exoplanets. We performed high-precision radial velocity spectroscopic observations of HD147506 (HAT-P-2) with the new spectrograph SOPHIE, mounted on the 1.93 m telescope at the Haute-Provence observatory (OHP). We obtained 63 new measurements, including 35 on May 14 and 20 on June 11, when the planet was transiting its parent star. The radial velocity (RV) anomaly observed illustrates that HAT-P-2b orbital motion is set in the same direction as its parent star spin. The sky-projected angle between the normal of the orbital plane and the stellar spin axis, \lambda = 0.2 +12.2 -12.5 deg, is consistent with zero. The planetary and stellar radii were re-determined, yielding R_p = 0.951 +0.039 -0.053 R_Jup, R_s = 1.416 +0.040 -0.062 R_Sun. The mass M_p = 8.62 +0.39 -0.55 M_Jup and radius of HAT-P-2b indicate a density of 12.5 +2.6 -3.6 g cm^{-3}, suggesting an object in between the known close-in planets with typical density of the order of 1 g cm^{-3}, and the very low-mass stars, with density greater than 50 g cm^{-3}.Comment: Submitted to A&A; V2: Replaced by accepted versio

Elodie metallicity-biased search for transiting Hot Jupiters IV. Intermediate period planets orbiting the stars HD43691 and HD132406

We report here the discovery of two planet candidates as a result of our planet-search programme biased in favour of high-metallicity stars, using the ELODIE spectrograph at the Observatoire de Haute Provence. One of them has a minimum mass m_2\sin{i} = 2.5 M_Jup and is orbiting the metal-rich star HD43691 with period P = 40 days and eccentricity e = 0.14. The other planet has a minimum mass m_2\sin{i} = 5.6 M_Jup and orbits the slightly metal-rich star HD132406 with period P = 974 days and eccentricity e = 0.34. Both stars were followed up with additional observations using the new SOPHIE spectrograph that replaces the ELODIE instrument, allowing an improved orbital solution for the systems.Comment: 6 pages, 4 figures, to be published in A&

Extrasolar planets and brown dwarfs around A-F type stars. IV. A candidate brown dwarf around the A9V pulsating star HD180777

We present here the detection of a brown dwarf orbiting the A9V star HD180777. The radial velocity measurements, obtained with the ELODIE echelle spectrograph at the Haute-Provence Observatory, show a main variation with a period of 28.4 days. Assuming a primary mass of 1.7 Mo, the best Keplerian fit to the data leads to a minimum mass of 25 MJup for the companion (the true mass could be significantly higher). We also show that, after substraction of the Keplerian solution from the radial velocity measurements, the residual radial velocities are related to phenomena intrinsic to the star, namely pulsations with typical periods of Gamma Dor stars. These results show that in some cases, it is possible to disentangle radial velocity variations due to a low mass companion from variations intrinsic to the observed star.Comment: 7 pages, final version, accepted for publication (A&A

Magnetically stimulable graphene Oxide/Polypropylene nanocomposites

Core–shell magnetic air-stable nanoparticles have attracted increasing interest in recent years. Attaining a satisfactory distribution of magnetic nanoparticles (MNPs) in polymeric matrices is difficult due to magnetically induced aggregation, and supporting the MNPs on a nonmagnetic core–shell is a well-established strategy. In order to obtain magnetically active polypropylene (PP) nanocomposites by melt mixing, the thermal reduction of graphene oxides (TrGO) at two different temperatures (600 and 1000 °C) was carried out, and, subsequently, metallic nanoparticles (Co or Ni) were dispersed on them. The XRD patterns of the nanoparticles show the characteristic peaks of the graphene, Co, and Ni nanoparticles, where the estimated sizes of Ni and Co were 3.59 and 4.25 nm, respectively. The Raman spectroscopy presents typical D and G bands of graphene materials as well as the corresponding peaks of Ni and Co nanoparticles. Elemental and surface area studies show that the carbon content and surface area increase with thermal reduction, as expected, following a reduction in the surface area by the support of MNPs. Atomic absorption spectroscopy demonstrates about 9–12 wt % metallic nanoparticles supported on the TrGO surface, showing that the reduction of GO at two different temperatures has no significant effect on the support of metallic nanoparticles. Fourier transform infrared (FT-IR) spectroscopy shows that the addition of a filler does not alter the chemical structure of the polymer. Scanning electron microscopy of the fracture interface of the samples demonstrates consistent dispersion of the filler in the polymer. The TGA analysis shows that, with the incorporation of the filler, the initial (Tonset) and maximum (Tmax) degradation temperatures of the PP nanocomposites increase up to 34 and 19 °C, respectively. The DSC results present an improvement in the crystallization temperature and percent crystallinity. The filler addition slightly enhances the elastic modulus of the nanocomposites. The results of the water contact angle confirm that the prepared nanocomposites are hydrophilic. Importantly, the diamagnetic matrix is transformed into a ferromagnetic one with the addition of the magnetic filler