Detecting Stellar Rotation with the Synchrosqueezing Wavelet Transform

The main goal of Gyrochronology is to determine stellar ages by understanding how stars slow down in their rotation as they age. In order to achieve such a goal, rotation periods must be determined with high precision. Various tools are available for determining stellar rotation periods, such as the AutoCorrelation Function (ACF), Lomb Scargle periodograms, or Classical Wavelet analysis. However, each method has strengths and weaknesses when applied to determining stellar rotation rates. One weakness of Classical Wavelet analysis is the relatively low precision with which periods are determined. A new algorithm for wavelet analysis, called Synchrosqueezing Wavelet Transform (SWT), claims to deliver more precise periods than the classical analysis. This poster presents the results of computing classical and SWT wavelet analysis rotation periods for a sample of 3912 stars that are components of wide binary systems. So far, the SWT results show a significant improvement in the precision of rotational periods, as expected. The SWT algorithm is likely to become part of the Gyrochronology team\u27s pipeline for stellar rotation period determinations. Support from NSF grants AST-1910396, AST-2108975 and NASA grants 80NSSC22K0622, 80NSSC21K0245, and NNX16AB76G is gratefully acknowledged

Gyrochronology: TESS Light Curve Analysis

Gyrochronology is the observed correlation between the age of a cool main-sequence star like the Sun and its rotational period. Various methods can be used to determine stellar rotation periods, however NASA’s Kepler mission and NASA’s Transiting Exoplanet Survey Satellite (TESS) mission provide complementary data for this type of project. Kepler focused on a very small observational field for almost four continuous years, whereas TESS continues to survey the entire night sky for intervals of about one month at a time. Due to this difference in cadence, it is important to compare the resulting rotation periods obtained from these surveys. We have constructed TESS light curves to compare to existing Kepler light curves of the same target stars observed at different epochs. Identifying the conditions under which TESS rotation periods may differ from those derived from the Kepler mission can help identify the random and systematic biases of each data set. This poster presents some preliminary results of this comparison. Support from NSF grants AST-1910396, AST-2108975 and NASA grants 80NSSC22K0622, 80NSSC21K0245, and NNX16AB76G is gratefully acknowledged. *Florida Gulf Coast Universit

Comparative study of simulated and observed blended light curves for unambiguous stellar rotation period determinations

Gyrochronology postulates that the age of stars similar in mass to our Sun can be approximated based on their rotational period. With this in mind, determining accurate rotation periods using photometry data from missions such as Kepler, K2, and TESS is vital for accurate stellar age estimates. Blended light curves pose a particular problem: When conducting simple aperture photometry, neighboring targets can taint the resulting light curve. In most cases, this issue makes the data unusable for unambiguous determination of stellar rotation periods. In this poster, we outline our research project, which aims to provide a solution to the issue of blended light curves. The project consists of computing a grid of simulated blended light curves and comparing them to observed blended photometric data from Kepler, K2, and TESS. Simulations will be computed using Butterpy, a Python package that yields the light curve of a particular model of starspots evolving through the stellar surface. We expect to quantitatively match any simulation from the grid to any of the blended light curves in our sample. Success in the project results will significantly impact other fields of astronomy that also use photometric data by facilitating a new collection of previously unusable data

Un examen actualizado de la percepción de las barreras para la implementación de la farmacogenómica y la utilidad de los pares fármaco/gen en América Latina y el Caribe

La farmacogenómica (PGx) se considera un campo emergente en los países en desarrollo. La investigación sobre PGx en la región de América Latina y el Caribe (ALC) sigue siendo escasa, con información limitada en algunas poblaciones. Por lo tanto, las extrapolaciones son complicadas, especialmente en poblaciones mixtas. En este trabajo, revisamos y analizamos el conocimiento farmacogenómico entre la comunidad científica y clínica de ALC y examinamos las barreras para la aplicación clínica. Realizamos una búsqueda de publicaciones y ensayos clínicos en este campo en todo el mundo y evaluamos la contribución de ALC. A continuación, realizamos una encuesta regional estructurada que evaluó una lista de 14 barreras potenciales para la aplicación clínica de biomarcadores en función de su importancia. Además, se analizó una lista emparejada de 54 genes/fármacos para determinar una asociación entre los biomarcadores y la respuesta a la medicina genómica. Esta encuesta se comparó con una encuesta anterior realizada en 2014 para evaluar el progreso en la región. Los resultados de la búsqueda indicaron que los países de América Latina y el Caribe han contribuido con el 3,44% del total de publicaciones y el 2,45% de los ensayos clínicos relacionados con PGx en todo el mundo hasta el momento. Un total de 106 profesionales de 17 países respondieron a la encuesta. Se identificaron seis grandes grupos de obstáculos. A pesar de los continuos esfuerzos de la región en la última década, la principal barrera para la implementación de PGx en ALC sigue siendo la misma, la "necesidad de directrices, procesos y protocolos para la aplicación clínica de la farmacogenética/farmacogenómica". Las cuestiones de coste-eficacia se consideran factores críticos en la región. Los puntos relacionados con la reticencia de los clínicos son actualmente menos relevantes. Según los resultados de la encuesta, los pares gen/fármaco mejor clasificados (96%-99%) y percibidos como importantes fueron CYP2D6/tamoxifeno, CYP3A5/tacrolimus, CYP2D6/opioides, DPYD/fluoropirimidinas, TMPT/tiopurinas, CYP2D6/antidepresivos tricíclicos, CYP2C19/antidepresivos tricíclicos, NUDT15/tiopurinas, CYP2B6/efavirenz y CYP2C19/clopidogrel. En conclusión, aunque la contribución global de los países de ALC sigue siendo baja en el campo del PGx, se ha observado una mejora relevante en la región. La percepción de la utilidad de las pruebas PGx en la comunidad biomédica ha cambiado drásticamente, aumentando la concienciación entre los médicos, lo que sugiere un futuro prometedor en las aplicaciones clínicas de PGx en ALC.Pharmacogenomics (PGx) is considered an emergent field in developing countries. Research on PGx in the Latin American and the Caribbean (LAC) region remains scarce, with limited information in some populations. Thus, extrapolations are complicated, especially in mixed populations. In this paper, we reviewed and analyzed pharmacogenomic knowledge among the LAC scientific and clinical community and examined barriers to clinical application. We performed a search for publications and clinical trials in the field worldwide and evaluated the contribution of LAC. Next, we conducted a regional structured survey that evaluated a list of 14 potential barriers to the clinical implementation of biomarkers based on their importance. In addition, a paired list of 54 genes/drugs was analyzed to determine an association between biomarkers and response to genomic medicine. This survey was compared to a previous survey performed in 2014 to assess progress in the region. The search results indicated that Latin American and Caribbean countries have contributed 3.44% of the total publications and 2.45% of the PGx-related clinical trials worldwide thus far. A total of 106 professionals from 17 countries answered the survey. Six major groups of barriers were identified. Despite the region’s continuous efforts in the last decade, the primary barrier to PGx implementation in LAC remains the same, the “need for guidelines, processes, and protocols for the clinical application of pharmacogenetics/pharmacogenomics”. Cost-effectiveness issues are considered critical factors in the region. Items related to the reluctance of clinicians are currently less relevant. Based on the survey results, the highest ranked (96%–99%) gene/drug pairs perceived as important were CYP2D6/tamoxifen, CYP3A5/tacrolimus, CYP2D6/opioids, DPYD/fluoropyrimidines, TMPT/thiopurines, CYP2D6/tricyclic antidepressants, CYP2C19/tricyclic antidepressants, NUDT15/thiopurines, CYP2B6/efavirenz, and CYP2C19/clopidogrel. In conclusion, although the global contribution of LAC countries remains low in the PGx field, a relevant improvement has been observed in the region. The perception of the usefulness of PGx tests in biomedical community has drastically changed, raising awareness among physicians, which suggests a promising future in the clinical applications of PGx in LAC

DataSheet1_Asteroseismic inferences from the study of non-linearities in δ Sct stars.PDF

Many pulsating star light curves must be interpreted strictly within the framework of a non-linear theory. The detection of non-linear interactions between pulsation modes has increased due to the ultra-precise photometric data provided by space missions. For this reason, it is now possible and essential to continue the effort of building data-driven non-linear pulsation models. The analysis of non-linear stellar light curves has become a fundamental challenge in asteroseismology in the era of space missions. In this article, a diagnostic method is presented. It is based on an observational characterization of the non-linear behavior of high-amplitude delta Scuti (HADS) stars. It diagnoses the nature of non-linear pulsations in δ Sct stars of lower amplitudes. It potentially provides an extra hint for identifying a radial mode and determine its radial order n. Additionally, it could show signatures of moderate to rapid rotation in these stars. Overall, this article shows the capabilities for making asteroseismic inferences from studying combination frequencies in δ Sct stars.</p

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curva de luz de HD41641 con gaps <br

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Logotipo del telescopio espacial CoRoT<br

Coarse Grain Spectral Analysis of the grass for delta Scuti stars

delta Scuti stars are far from being understood as much as solar-like pulsators. One of the open questions on these stars started with the first long-run observations of CoRoT from space. To observe the so-called grass (i.e. the low-amplitude signature of their power spectra), long duration, high photometric precision and high duty cycle light curves are needed which are impossible to gather from ground-based observatories. Its origin is still a long-standing debate but the presence of a flat plateau may be related with extrinsic or intrinsic processes of this kind of stars such as fast rotation. Here we deeply study the grass not only analysing the reliable harmonic variations but using the Coarse Grain Spectral Analysis (CGSA) to characterize its fractal signature. We applied this methodology to a sample of well-known delta Scuti stars observed by TESS space telescope approximately for a year. Our results point to a dependence of the grass with rotation and also with time

ET White Paper: To Find the First Earth 2.0

We propose to develop a wide-field and ultra-high-precision photometric survey mission, temporarily named "Earth 2.0 (ET)". This mission is designed to measure, for the first time, the occurrence rate and the orbital distributions of Earth-sized planets. ET consists of seven 30cm telescopes, to be launched to the Earth-Sun's L2 point. Six of these are transit telescopes with a field of view of 500 square degrees. Staring in the direction that encompasses the original Kepler field for four continuous years, this monitoring will return tens of thousands of transiting planets, including the elusive Earth twins orbiting solar-type stars. The seventh telescope is a 30cm microlensing telescope that will monitor an area of 4 square degrees toward the galactic bulge. This, combined with simultaneous ground-based KMTNet observations, will measure masses for hundreds of long-period and free-floating planets. Together, the transit and the microlensing telescopes will revolutionize our understandings of terrestrial planets across a large swath of orbital distances and free space. In addition, the survey data will also facilitate studies in the fields of asteroseismology, Galactic archeology, time-domain sciences, and black holes in binaries.Comment: 116 pages,79 figure