Two new pulsating low-mass pre-white dwarfs or SX Phenix stars?*

Context. The discovery of pulsations in low-mass stars opens an opportunity for probing their interiors and to determine their evolution, by employing the tools of asteroseismology. Aims. We aim to analyze high-speed photometry of SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25 and discover brightness variabilities. In order to locate these stars in the $T_{\rm eff} - \log g$ diagram we fit optical spectra (SDSS) with synthetic non-magnetic spectra derived from model atmospheres. Methods. To carry out this study, we used the photometric data obtained by us for these stars with the 2.15m telescope at CASLEO, Argentina. We analyzed their light curves and we apply the Discrete Fourier Transform to determine the pulsation frequencies. Finally, we compare both stars in the $T_{\rm eff} - \log g$ diagram, with known two pre-white dwarfs, seven pulsating pre-ELM white dwarf stars, $\delta$ Scuti and SX Phe stars. Results. We report the discovery of pulsations in SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25. We determine their effective temperature and surface gravity to be $T_{\rm eff}$ = 7 972 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5 and $T_{\rm eff}$ = 7 925 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5, respectively. With these parameters these new pulsating low-mass stars can be identified with either ELM white dwarfs (with ~ 0.17 Mo) or more massive SX Phe stars. We identified pulsation periods of 3 278.7 and 1 633.9 s for SDSSJ145847.02$+$070754.46 and a pulsation period of 3 367.1 s for SDSSJ173001.94$+$070600.25. These two new objects together with those of Maxted et al. (2013, 2014) indicate the possible existence of a new instability domain towards the late stages of evolution of low-mass white dwarf stars, although their identification with SX Phe stars cannot be discarded.Comment: 5 pages, 5 figures, 1 table, accepted for publication in A&A

Asteroseismology of the heartbeat star KIC 5006817

This paper summarizes the project work on asteroseismology at the ERASMUS+ GATE 2020 Summer school on space satellite data. The aim was to do a global asteroseismic analysis of KIC 5006817 and quantify its stellar properties using the high-quality, state of the art space missions data. We employed the aperture photometry to analyze the data from the Kepler space telescope and the Transiting Exoplanet Survey Satellite (TESS). Using the lightkurve Python package, we have derived the asteroseismic parameters and calculated the stellar parameters using the scaling relations. Our analysis of KIC 5006817 confirmed its classification as a heartbeat binary. The rich oscillation spectrum facilitate estimating power excess ($\nu_{\rm max}$) at 145.50$\pm$0.50 $\mu$Hz and large frequency separation ($\Delta\nu$) to be 11.63$\pm$0.10 $\mu$Hz. Our results showed that the primary component is a low-luminosity, red-giant branch star with a mass, radius, surface gravity, and luminosity of 1.53$\pm$0.07 M$_\odot$, 5.91$\pm$0.12 R$_\odot$, 3.08$\pm$0.01 dex, and 19.66$\pm$0.73 L$_\odot$, respectively. The orbital period of the system is 94.83$\pm$0.05 d.Comment: 13 pages, 4 figures, 2 tables; Based on the project work at ERASMUS+ GATE 2020 Summer school; To be published in Contrib. Astron. Obs. Skalnat\'e Ples

SÍNDROME DE BURNOUT, SATISFACCIÓN LABORAL Y RELACIONES INTERPERSONALES EN PROFESORES DE UNA INSTITUCIÓN EDUCATIVA DE AREQUIPA

En la presente investigación, se valoran las relaciones entre el síndrome de burnout, la satisfacción laboral y las relaciones interpersonales en un grupo de profesores de la ciudad de Arequipa. Para ello, se evaluó a 46 profesores de una institución educativa privada de esta ciudad, con el inventario de Burnout de Maslach, la Escala de Satisfacción Laboral de Warr, Cook y Wall, y la escala de Satisfacción de las Relaciones Interpersonales en el Trabajo. Todos estos instrumentos cuentan con propiedades psicométricas adecuadas para la ciudad de Arequipa. Los resultados indican que existen relaciones negativas y moderadas entre la satisfacción laboral y el síndrome de burnout, pero no con las relaciones interpersonales. No se encontraron diferencias significativas en función del sexo o el cargo de los profesores, y la satisfacción laboral intrínseca tuvo un efecto predictivo significativo y negativo sobre el síndrome de burnout

Spectral classification and HR diagram of pre-main sequence stars in NGC6530

Mechanisms involved in the star formation process and in particular the duration of the different phases of the cloud contraction are not yet fully understood. Photometric data alone suggest that objects coexist in the young cluster NGC6530 with ages from ~1 Myr up to 10 Myrs. We want to derive accurate stellar parameters and, in particular, stellar ages to be able to constrain a possible age spread in the star-forming region NGC6530. We used low-resolution spectra taken with VIMOS@VLT and literature spectra of standard stars to derive spectral types of a subsample of 94 candidate members of this cluster. We assign spectral types to 86 of the 88 confirmed cluster members and derive individual reddenings. Our data are better fitted by the anomalous reddening law with R$_{\rm V}$=5. We confirm the presence of strong differential reddening in this region. We derive fundamental stellar parameters, such as effective temperatures, photospheric colors, luminosities, masses, and ages for 78 members, while for the remaining 8 YSOs we cannot determine the interstellar absorption, since they are likely accretors, and their V-I colors are bluer than their intrinsic colors. The cluster members studied in this work have masses between 0.4 and 4 M$_\odot$ and ages between 1-2 Myrs and 6-7 Myrs. We find that the SE region is the most recent site of star formation, while the older YSOs are loosely clustered in the N and W regions. The presence of two distint generations of YSOs with different spatial distribution allows us to conclude that in this region there is an age spread of ~6-7 Myrs. This is consistent with the scenario of sequential star formation suggested in literature.Comment: 23 pages, 16 Postscript figures, 5 tables. Accepted for publication in Astronomy and Astrophysic

Unveiling the evolutionary state of three B supergiant stars: PU Gem, ϵ\epsilon CMa and η\eta CMa

We aim to combine asteroseismology, spectroscopy, and evolutionary models to establish a comprehensive picture of the evolution of Galactic blue supergiant stars (BSG). To start such an investigation, we selected three BSG candidates for our analysis: HD 42087 (PU Gem), HD 52089 ($\epsilon$ CMa) and HD 58350 ($\eta$ CMa). These stars show pulsations and were suspected to be in an evolutionary stage either preceding or succeding the red supergiant (RSG) stage. For our analysis, we utilized the 2-min cadence TESS data to study the photometric variability and obtained new spectroscopic observations at the CASLEO observatory. We calculated CMFGEN non-LTE radiative transfer models and derived stellar and wind parameters using the iterative spectral analysis pipeline XTGRID. The spectral modeling was limited to changing only the effective temperature, surface gravity, CNO abundances, and mass-loss rates. Finally, we compared the derived metal abundances with predictions from Geneva stellar evolution models. The frequency spectra of all three stars show either stochastic oscillations, nonradial strange modes, or a rotational splitting. We conclude that the rather short sectoral observing windows of TESS prevent establishing a reliable mode identification of low frequencies connected to mass-loss variabilities. The spectral analysis confirmed gradual changes in the mass-loss rates and the derived CNO abundances comply with the values reported in the literature. We were able to achieve a quantitative match with stellar evolution models for the stellar masses and luminosities. However, the spectroscopic surface abundances turned out to be inconsistent with theoretical predictions. The stars show N enrichment, typical for CNO cycle processed material, but the abundance ratios do not reflect the associated levels of C and O depletion.Comment: 29 pages, 18 figures, Accepted for publication in Galaxie

Depresión de adultos mayores en residentes de un asilo y en un grupo de la comunidad en la ciudad de Toluca 2016

Objetivo: Analizar el grado de depresión en adultos mayores de dos grupos: residentes de un asilo en la ciudad de Toluca y el grupo semanal del DIF de la comunidad de San Mateo Tlachichilpan, municipio de Almoloya de Juárez. Material y Métodos: Es un estudio cuantitativo de tipo descriptivo y transversal, la muestra es probabilística por conveniencia integrado por 20 adultos mayores del asilo y 31 adultos mayores del programa comunitario del DIF municipal de Almoloya de Juárez. Se utilizó las escalas de Yesavage y de Beck, y se realizó su análisis estadístico a través del programa SSPS versión 22.0 en español. Resultados: Se utilizó un total de 51 instrumentos para la recolección de datos, 37.3% fueron hombres y 62.7% mujeres. La descripción del estado civil es: solteros 41%, casados 11.8% y viudos 47.1%, en la situación laboral 86.3% son desempleados. Se utilizó la escala de Yesavage: 66.7% sin depresión, 25.5% depresión leve y 7.8% depresión establecida. La escala de Beck normal o no depresión de 54.9%, depresión leve 39.2% y depresión moderada 5.9%. Conclusiones: El grado de depresión fue mayor en el asilo, en ambas valoraciones es mayor el grado de depresión en las personas que no reciben visitas, la depresión leve se presenta en ambos lugares. En la mayoría de los casos no se había integrado un diagnóstico de depresión. Abstract Objective: Analyze the degree of depression in older adults in two groups: residents of a nursing home in the city of Toluca and weekly group DIF community of San Mateo Tlachichilpan, municipality of Almoloya de Juarez. Materials and Methods: This research is quantitative descriptive approach and cross type, the sample was composed by convenience of 20 older adults and 31 elderly asylum Community program municipal DIF of Almoloya de Juarez. Yesavage scales and Beck were applied, statistical analysis was performed using the SSPS 22.0 program version in Spanish. Results: A total of 51 instruments for data collection, 37.3% were men and 62.7% were applied were women. The description of marital status is single 41%; married 11.8% and widowers 47.1% in the employment situation 86.3% are unemployed. Yesavage scale 25.5% 7.8% mild depression and depression set, Beck normal scale depression or 54.9%, 39.2% mild depression and moderate depression 5.9% was applied with a percentage of 66.7% without depression. Conclusions: The degree of depression was higher in the asylum in both assessments, the greater the degree of depression in people not receiving visits, mild depression occurs in both places, in most cases had not made a diagnosis of depression. &nbsp