Relativistic quantum motion of spin-0 particles under the influence of non-inertial effects in the cosmic string space-time

We study solutions for the Klein-Gordon equation with vector and scalar potentials of the Coulomb types under the influence of non-inertial effects in the space-time of topological defects. We also investigate a quantum particle described by the Klein-Gordon oscillator in the background space-time generated by a string. An important result obtained is that the non-inertial effects restrict the physical region of the space-time where the particle can be placed. In addition, we show that these potentials can form bound states for the relativistic wave equation equation in this kind of background.Comment: arXiv admin note: text overlap with arXiv:1608.0669

Klein-Gordon oscillator in a topologically nontrivial space-time

In this study, we analyze solutions of the wave equation for scalar particles in a space-time with nontrivial topology. Solutions for the Klein--Gordon oscillator are found considering two configurations of this space-time. In the first one, it is assumed the $S^{1}\times R^{3}$ space where the metric is written in the usual inertial frame of reference. In the second case, we consider a rotating reference frame adapted to the circle S1. We obtained compact expressions for the energy spectrum and for the particles wave functions in both configurations. Additionally, we show that the energy spectrum of the solution associated to the rotating system has an additional term that breaks the symmetry around $E = 0$

Detecting transit signatures of exoplanetary rings using SOAP3.0

CONTEXT. It is theoretically possible for rings to have formed around extrasolar planets in a similar way to that in which they formed around the giant planets in our solar system. However, no such rings have been detected to date. AIMS: We aim to test the possibility of detecting rings around exoplanets by investigating the photometric and spectroscopic ring signatures in high-precision transit signals. METHODS: The photometric and spectroscopic transit signals of a ringed planet is expected to show deviations from that of a spherical planet. We used these deviations to quantify the detectability of rings. We present SOAP3.0 which is a numerical tool to simulate ringed planet transits and measure ring detectability based on amplitudes of the residuals between the ringed planet signal and best fit ringless model. RESULTS: We find that it is possible to detect the photometric and spectroscopic signature of near edge-on rings especially around planets with high impact parameter. Time resolution $\leq$ 7 mins is required for the photometric detection, while 15 mins is sufficient for the spectroscopic detection. We also show that future instruments like CHEOPS and ESPRESSO, with precisions that allow ring signatures to be well above their noise-level, present good prospects for detecting rings.Comment: 13 pages, 16 figures, 2 tables , accepted for publication in A&

Experience with the Open Source based implementation for ATLAS Conditions Data Management System

Conditions Data in high energy physics experiments is frequently seen as every data needed for reconstruction besides the event data itself. This includes all sorts of slowly evolving data like detector alignment, calibration and robustness, and data from detector control system. Also, every Conditions Data Object is associated with a time interval of validity and a version. Besides that, quite often is useful to tag collections of Conditions Data Objects altogether. These issues have already been investigated and a data model has been proposed and used for different implementations based in commercial DBMSs, both at CERN and for the BaBar experiment. The special case of the ATLAS complex trigger that requires online access to calibration and alignment data poses new challenges that have to be met using a flexible and customizable solution more in the line of Open Source components. Motivated by the ATLAS challenges we have developed an alternative implementation, based in an Open Source RDBMS. Several issues were investigated land will be described in this paper: -The best way to map the conditions data model into the relational database concept considering what are foreseen as the most frequent queries. -The clustering model best suited to address the scalability problem. -Extensive tests were performed and will be described. The very promising results from these tests are attracting the attention from the HEP community and driving further developments.Comment: 8 pages, 4 figures, 3 tables, conferenc

Distinguishing the albedo of exoplanets from stellar activity

Light curves show the flux variation from the target star and its orbiting planets as a function of time. In addition to the transit features created by the planets, the flux also includes the reflected light component of each planet, which depends on the planetary albedo. This signal is typically referred to as phase curve and could be easily identified if there were no additional noise. As well as instrumental noise, stellar activity, such as spots, can create a modulation in the data, which may be very difficult to distinguish from the planetary signal. We analyze the limitations imposed by the stellar activity on the detection of the planetary albedo, considering the limitations imposed by the predicted level of instrumental noise and the short duration of the observations planned in the context of the CHEOPS mission. As initial condition, we have assumed that each star is characterized by just one orbiting planet. We built mock light curves that included a realistic stellar activity pattern, the reflected light component of the planet and an instrumental noise level, which we have chosen to be at the same level as predicted for CHEOPS. We then fit these light curves to try to recover the reflected light component, assuming the activity patterns can be modeled with a Gaussian process.We estimate that at least one full stellar rotation is necessary to obtain a reliable detection of the planetary albedo. This result is independent of the level of noise, but it depends on the limitation of the Gaussian process to describe the stellar activity when the light curve time-span is shorter than the stellar rotation. Finally, in presence of typical CHEOPS gaps in the simulations, we confirm that it is still possible to obtain a reliable albedo.Comment: Accepted for publication in A&A, 14 pages, 12 figure

Constraining planet structure and composition from stellar chemistry: trends in different stellar populations

The chemical composition of stars that have orbiting planets provides important clues about the frequency, architecture, and composition of exoplanet systems. We explore the possibility that stars from different galactic populations that have different intrinsic abundance ratios may produce planets with a different overall composition. We compiled abundances for Fe, O, C, Mg, and Si in a large sample of solar neighbourhood stars that belong to different galactic populations. We then used a simple stoichiometric model to predict the expected iron-to-silicate mass fraction and water mass fraction of the planet building blocks, as well as the summed mass percentage of all heavy elements in the disc. Assuming that overall the chemical composition of the planet building blocks will be reflected in the composition of the formed planets, we show that according to our model, discs around stars from different galactic populations, as well as around stars from different regions in the Galaxy, are expected to form rocky planets with significantly different iron-to-silicate mass fractions. The available water mass fraction also changes significantly from one galactic population to another. The results may be used to set constraints for models of planet formation and chemical composition. Furthermore, the results may have impact on our understanding of the frequency of planets in the Galaxy, as well as on the existence of conditions for habitability.Comment: Accepted for publication in Astronomy & Astrophysic