Kepler-539: a young extrasolar system with two giant planets on wide orbits and in gravitational interaction

We confirm the planetary nature of Kepler-539b (aka Kepler object of interest K00372.01), a giant transiting exoplanet orbiting a solar-analogue G2 V star. The mass of Kepler-539b was accurately derived thanks to a series of precise radial velocity measurements obtained with the CAFE spectrograph mounted on the CAHA 2.2m telescope. A simultaneous fit of the radial-velocity data and Kepler photometry revealed that Kepler-539b is a dense Jupiter-like planet with a mass of Mp = 0.97 Mjup and a radius of Rp = 0.747 Rjup, making a complete circular revolution around its parent star in 125.6 days. The semi-major axis of the orbit is roughly 0.5 au, implying that the planet is at roughly 0.45 au from the habitable zone. By analysing the mid-transit times of the 12 transit events of Kepler-539b recorded by the Kepler spacecraft, we found a clear modulated transit time variation (TTV), which is attributable to the presence of a planet c in a wider orbit. The few timings available do not allow us to precisely estimate the properties of Kepler-539c and our analysis suggests that it has a mass between 1.2 and 3.6 Mjup, revolving on a very eccentric orbit (0.4<e<0.6) with a period larger than 1000 days. The high eccentricity of planet c is the probable cause of the TTV modulation of planet b. The analysis of the CAFE spectra revealed a relatively high photospheric lithium content, A(Li)=2.48 dex, which, together with both a gyrochronological and isochronal analysis, suggests that the parent star is relatively young.Comment: 11 pages, 14 figures, accepted for publication in Astronomy & Astrophysic

Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)

In this paper we continue the release of high-level data products from the multiyear photometric survey collected at the 67/92 cm Schmidt Telescope in Asiago. The primary goal of the survey is to discover and to characterise variable objects and exoplanetary transits in four fields containing five nearby open clusters spanning a broad range of ages. This second paper releases a photometric catalogue, in five photometric bands, of the Solar-age, Solar-metallicity open cluster M 67 (NGC 2682). Proper motions are derived comparing the positions observed in 2013 at the Asiago's Schmidt Telescope with those extracted from [email protected] MPG/ESO images in 2000. We also analyse the variable sources within M 67. We detected 68 variables, 43 of which are new detection. Variable periods and proper-motion memberships of a large majority of sources in our catalogue are improved with respect to previous releases. The entire catalogue will be available in electronic format. Besides the general interest on an improved catalogue, this work will be particularly useful because of: (1) the imminent release of Kepler/K2 Campaign-5 data of this cluster, for which our catalogue will provide an excellent, high spatial resolution input list, and (2) characterisation of the M 67 stars which are targets of intense HARPS and HARPS-N radial-velocity surveys for planet search.Comment: 8 pages, 6 figures (2 at low resolution), 2 tables. Accepted for publication in MNRAS on October 17, 2015. Electronic materials available at the url http://groups.dfa.unipd.it/ESPG/M67.html , and later on the Journal and at the CD

The low-energy limit of AdS(3)/CFT2 and its TBA

We investigate low-energy string excitations in AdS3 × S3 × T4. When the worldsheet is decompactified, the theory has gapless modes whose spectrum at low energies is determined by massless relativistic integrable S matrices of the type introduced by Al. B. Zamolodchikov. The S matrices are non-trivial only for excitations with identical worldsheet chirality, indicating that the low-energy theory is a CFT2. We construct a Thermodynamic Bethe Ansatz (TBA) for these excitations and show how the massless modes’ wrapping effects may be incorporated into the AdS3 spectral problem. Using the TBA and its associated Y-system, we determine the central charge of the low-energy CFT2 to be c = 6 from calculating the vacuum energy for antiperiodic fermions — with the vacuum energy being zero for periodic fermions in agreement with a supersymmetric theory — and find the energies of some excited states

Características físico-químicas de meis produzidos por espécies de meliponíneos.

Além da abelhas Africanizadas (Apis mellifera L.), as abelhas indígenas sem ferrão ou meliponíneos (Meliponinae) são potenciais produtoras de mel. Esse produto apresenta carcterísticas distintas do mel produzido pelas abelhas do gênero Apis, sendo muito apreciado pelos consumidores. Entretanto, são escassos os dados científicos a respeito da composição desse mel na literatura nacional e internacional. A proposta deste trabalho é avaliar as características físico-químicas do mel produzido por meliponíneos. As análises físico-químico foram realizadas de acordo com as técnicas descritas pela AOAC (Association of Official Analytical Chemists), e pela European Honey Comission, conforme recomendado pela CAC (Codex Alimentarius Comission). Os resultados obtidos reforçam a necessidade do desenvolvimento de um padrão próprio para os méis de abelhas sem ferrão, incluindo critérios microbiológicos.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010

Teor de óleo essencial de Ocimum selloi Benth. sob diferentes doses de compostos orgânicos.

Em espécies bioativas, a aplicação de compostos orgânicos tem sido relacionada à produção de metabólitos secundários. No presente estudo, avaliou-se o efeito de diferentes doses de compostos orgânicos no teor de óleo essencial de alfavaca anisada, fornecendo bases científicas para agricultura orgânica. Em Curitiba-PR, ano de 2008, num delineamento em blocos ao acaso, com três repetições, doses (0, 0,85, 1,7 e 3 t.ha-1) de compostos estabilizados (A, B, C e D), elaborados com diferentes materiais orgânicos, foram utilizadas no cultivo de alfavaca anisada. O espaçamento utilizado em cultivo protegido irrigado foi de 0,5m entre linhas por 1,0m entre plantas. Aos seis meses de cultivo, amostras compostas de folhas foram coletadas e submetidas ao processo de hidrodestilação, por meio do aparelho do tipo Clevenger, para quantificação do óleo essencial. Em solo com acúmulo de matéria orgânica as doses e compostos avaliados não influenciaram o teor de óleo essencial de Ocimum selloi Beth.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010

MONTHLY ISOTOPIC SIGNAL OF THE PRECIPITATED WATER IN THE PROVINCE OF TRENTO: LAGRANGIAN ANALYSIS AND DISCUSSION OF MEASUREMENTS

The present work has been performed in the framework of the research project AQUAPAST. The main focus of AQUAPAST is the reconstruction of past climate changes in the atmospheric circulation and in particular in the water vapour transport mechanism over the Mediterranean area starting from the analysis of the isotopic content of cave speleothemes in the Trentino Province (North-East of Italy). A Lagrangian methodology for the reconstruction and the analysis of the airstreams which govern the transport of water vapour has been applied to recent events. The average monthly isotopic signal of the precipitation water sampled in stations located in key geographic settings in the Province of Trento is used as tracer to infer the origin of the precipitating water and to validate the Lagrangian analysis. A comparison between the isotopic signal of November 2002 and November 2003 is here presented, as most of the yearly precipitation falls in November over the Eastern Alps. Hypotheses are proposed about the meteorological factors (e.g. monthly averaged sea surface temperature, atmospheric circulation, etc.) determining different isotopic signals in the two years

Sustainability assessment of agriculture water use under water scarcity limitation and climate change adaptation

Irrigation accounts for about 70% of the global freshwater withdrawals and 90% of consumptive water uses. With 40% of irrigation water consumption occurring in water scarce areas, there is a need to understand to what extent freshwater can be sustainably used in agriculture without compromising environmental flows or depleting groundwater stocks. To date, methods that can be used to evaluate the vulnerability of the water system to climate change and the sustainability of water use for irrigation often fail to provide an integrated analysis of the biophysical and economic dimensions of water use. Here we develop a new approach to evaluate the sustainability of water use in agriculture in conditions of water scarcity. We propose a framework that accounts for both socio-economic and environmental aspects of water sustainability based on three criteria expressing the reliability, resilience, and vulnerability of irrigation. Reliability is calculated as the probability that the system is able to meet irrigation need (i.e. irrigation water demand does not exceed water availability). Resilience expresses the system\u2019s ability to adapt to a changing condition and recover from a shock (i.e. a drought or conditions of water stress). Vulnerability is the magnitude (or \u2018severity\u2019) of the water deficit (i.e. insufficient irrigation water availability) the system is exposed to. Similar metrics are used to characterize the economic sustainability of irrigation. The evaluation of performance is based on the frequency of a deficit situation on each dimension of sustainability. The criteria of performance are aggregated into sub-indicators for each dimension of sustainability. The application of this framework to the case of Australian agriculture for the 2002-2016 period shows that Australia suffers from a high level of water scarcity, especially during the growing season. The analysis of the framework highlights the sustainability and unsustainability of the Australian water use system both in space and time. This analysis informs new criteria for managing a sustainable use of water resources, which is becoming challenging for stakeholders. Farmers need to adopt water management approaches that allow for a sustainable water use for irrigation and overcome water scarcity constraints

A possibly inflated planet around the bright, young star DS Tuc A

The origin of the observed diversity of planetary system architectures is one of the main topic of the exoplanetary research. The detection of a statistically significant sample of planets around young stars allows us to study the early stages of planet formation and evolution, but only a handful of them is known so far. In this regard, a considerable contribution is expected from the NASA TESS satellite, which is now performing a survey of $\sim 85 \%$ of the sky to search for short-period transiting planets In its first month of operations, TESS found a planet candidate with an orbital period of 8.14 days around a member of the Tuc-Hor young association ($\sim$ 40 Myr), the G6V main component of the binary system DS\,Tuc. If confirmed, it would be the first transiting planet around a young star suitable for radial velocity and/or atmospheric characterization. We aim to validate the planetary nature of this companion and to measure its orbital and physical parameters. We obtain accurate planet parameters by coupling an independent reprocessing of the TESS light curve with improved stellar parameters and the dilution caused by the binary companion; we analyse high precision archival radial velocities to impose an upper limit of about 0.1 M$_{\rm Jup}$ on the planet mass; we finally rule out the presence of external companions beyond 40 au with adaptive optics images. We confirm the presence of a young, giant (${\rm R} = 0.50$ R$_{\rm Jup}$) planet having a not negligible possibility to be inflated (theoretical mass $\lesssim 20$ M$_{\oplus}$) around DS\,Tuc~A. We discuss the feasibility of mass determination, Rossiter-McLaughlin analysis and atmosphere characterization, allowed by the brightness of the star.Comment: 12 pages, 11 figures. Accepted for publication in A&