0000000000054941
AUTHOR
P. D. Diago
The B0.5IVe CoRoT target HD 49330. I. Photometric analysis from CoRoT data
International audience; Context: Be stars undergo outbursts producing a circumstellar disk from the ejected material. The beating of non-radial pulsations has been put forward as a possible mechanism of ejection. Aims: We analyze the pulsational behavior of the early B0.5IVe star HD 49330 observed during the first CoRoT long run towards the Galactical anticenter (LRA1). This Be star is located close to the lower edge of the beta Cephei instability strip in the HR diagram and showed a 0.03 mag outburst during the CoRoT observations. It is thus an ideal case for testing the aforementioned hypothesis. Methods: We analyze the CoRoT light curve of HD 49330 using Fourier methods and non-linear le…
The B0.5 IVe CoRoT target HD 49330. II. Spectroscopic ground-based observations
International audience; Context: We present spectroscopic ground-based observations of the early Be star HD 49330 obtained simultaneously with the CoRoT-LRA1 run just before the burst observed in the CoRoT data. Aims: Ground-based spectroscopic observations of the early Be star HD 49330 obtained during the precursor phase and just before the start of an outburst allow us to disantangle stellar and circumstellar contributions and identify modes of stellar pulsations in this rapidly rotating star. Methods: Time series analysis (TSA) is performed on photospheric line profiles of He I and Si III by means of the least squares method. Results: We find two main frequencies f1 = 11.86 c d-1 and f2 …
Pulsating B and Be stars in the Small Magellanic Cloud
Context: Stellar pulsations in main-sequence B-type stars are driven by the kappa-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B spectral domain at very low metallicities. As the metallicity of the SMC is lower than Z=0.005, it constitutes a very suitable object to test these predictions. Aims: The main objective is to investigate the existence of B-type pulsators at low metallicities, searching for short-term periodic variability in absorption-line B and Be stars in the SMC. The analysis has been performed in a sample of 313 B and Be stars with fundamental astrophysical parameters accurately determined from high-res…
The Acquisition of Computational Thinking through Mentoring: An Exploratory Study
Educational robotics are commonly present in kindergarten and primary school classrooms, particularly Bee-bot. Its ease of use allows the introduction of computer programming to young children in educational contexts from a science, technology, engineering, arts, and mathematics (STEAM) perspective. Despite this rise, there are still few investigations that collect evidence on the effectiveness of robotic interventions. Although mentoring experiences with robotics had been carried out in educational contexts, this work explores their effect on the acquisition of computational thinking skills through mentoring. Participants from the second grade, aged seven through eight years, were exposed …
Photometric and spectroscopic variability of the B5IIIe star HD 171219
We analyzed the star HD 171219, one of the relatively bright Be stars observed in the seismo field of the CoRoT satellite, in order to determine its physical and pulsation characteristics. Classical Be stars are main-sequence objects of mainly B-type, whose spectra show, or have shown at some epoch, Balmer lines in emission and an infrared excess. Both characteristics are attributed to an equatorially concentrated circumstellar disk fed by non-periodic mass-loss episodes (outbursts). Be stars often show nonradial pulsation gravity modes and, as more recently discovered, stochastically excited oscillations. Applying the CLEANEST algorithm to the high-cadence and highly photometrically precis…
Pulsating B and Be Stars in the Magellanic Clouds
Stellar pulsations in main-sequence B-type stars are driven by the κ-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B spectral domain at very low metallicities. As the metallicity of the Magellanic Clouds (MC) has been measured to be around Z = 0. 002 for the Small Magellanic Cloud (SMC) and Z = 0. 007 for the Large Magellanic Cloud (LMC), they constitute a very suitable objects to test these predictions. The aim of this work is to investigate the existence of B-type pulsators at low metallicities, searching for short-term periodic variability in a large sample of B and Be stars from the MC with accurately determined f…
Exploring the development of mental rotation and computational skills in elementary students through educational robotics
Abstract Interest in educational robotics has increased over the last decade. Through various approaches, robots are being used in the teaching and learning of different subjects at distinct education levels. The present study investigates the effects of an educational robotic intervention on the mental rotation and computational thinking assessment in a 3rd grade classroom. To this end, we carried out a quasi-experimental study involving 24 third-grade students. From an embodied approach, we have designed a two-hour intervention providing students with a physical environment to perform tangible programming on Bee-bot. The results revealed that this educational robotic proposal aimed at map…
Fundamentos de diseño de un entorno tecnológico para el estudio de las habilidades en resolución de problemas en primeras edades escolares
En este trabajo se presentan los fundamentos de diseno de un software capaz de monitorizar y registrar datos referentes a la gestion de procesos de resolucion de problemas matematicos. El software permite una recogida sistematica de las variables del proceso de resolucion a partir de las cuales es posible obtener diferentes metricas de aprendizaje del estudiante. Al no centrar la atencion exclusivamente en el resultado final del proceso de resolucion, es posible identificar tendencias cognitivas de los estudiantes. En este manuscrito describimos las caracteristicas de este entorno tecnologico junto con la base didactica que justifica el interes de la investigacion en niveles escolares en …
Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452
International audience; Context. Be stars are rapidly rotating stars with a circumstellar decretion disk. They usually undergo pressure and/or gravity pulsation modes excited by the κ-mechanism, i.e. an effect of the opacity of iron-peak elements in the envelope of the star. In the Milky Way, p-modes are observed in stars that are hotter than or equal to the B3 spectral type, while g-modes are observed at the B2 spectral type and cooler. Aims. We observed a B0IVe star, HD 51452, with the high-precision, high-cadence photometric CoRoT satellite and high-resolution, ground-based HARPS and SOPHIE spectrographs to study its pulsations in great detail. We also used the lower resolution spectra a…
Relación entre complejidad y dificultad en tareas con patrones lineales reiterativos en estudiantes de 5 años
Una de las finalidades de la enseñanza de las matemáticas en Educación Infantil es fomentar el pensamiento lógico, la creatividad y la capacidad para resolver problemas de los estudiantes. Entre las actividades escolares propias de estas edades es habitual encontrar tareas de identificación y continuación de patrones lineales de repetición. Esta actividad puede ser estudiada desde un contexto de resolución de problemas en el que el estudiante debe discriminar la información superflua de aquella que le permite obtener la regla de generación de la serie y resolver la tarea. Diferentes variables como la longitud del núcleo de repetición, el número de descriptores, su naturaleza o la aparición …
Photometric variability of the Be star CoRoT-ID 102761769
Classical Be stars are rapid rotators of spectral type late O to early A and luminosity class V-III, wich exhibit Balmer emission lines and often a near infrared excess originating in an equatorially concentrated circumstellar envelope, both produced by sporadic mass ejection episodes. The causes of the abnormal mass loss (the so-called Be phenomenon) are as yet unknown. For the first time, we can now study in detail Be stars outside the Earth's atmosphere with sufficient temporal resolution. We investigate the variability of the Be Star CoRoT-ID 102761769 observed with the CoRoT satellite in the exoplanet field during the initial run. One low-resolution spectrum of the star was obtained wi…
On Augmented Reality for the Learning of 3D-Geometric Contents: A Preliminary Exploratory Study with 6-Grade Primary Students
Nowadays, Augmented Reality (AR) is one of the emerging technologies with a greater impact in the Education field. Research has proved that AR-based activities improve the teaching and learning processes. Also, the use of this type of technology in classroom facilitates the understanding of contents from different areas as Arts, Mathematics or Science. In this work we propose an AR-based instruction in order to explore the benefits in a 6th-grade Primary course related to 3D-geometry shapes. This first experiment, designed from an exploratory approach, will shed light on new study variables to perform new implementations whose conclusions become more consistent. The results obtained allow u…
Low-amplitude variations detected by CoRoT in the B8IIIe star HD 175869
International audience; Context: The origin of the short-term variability in Be stars remains a matter of controversy. Pulsations and rotational modulation are the components of the favored hypothesis. Aims: We present our analysis of CoRoT data of the B8IIIe star HD 175869 observed during the first short run in the center direction (SRC1). Methods: We review both the instrumental effects visible in the CoRoT light curve and the analysis methods used by the CoRoT Be team. We applied these methods to the CoRoT light curve of the star HD 175869. A search for line-profile variations in the spectroscopic data was also performed. We also searched for a magnetic field, by applying the LSD techniq…
Pulsations in the late-type Be star HD 50 209 detected by CoRoT
The presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars. To contribute to this discussion, we analyse the photometric time series of the B8IVe star HD 50209 observed by the CoRoT mission in the seismology field. We use standard Fourier techniques and linear and non-linear least squares fitting methods to analyse the CoRoT light curve. In addition, we applied detailed modelling of high-resolution spectra to obtain the fundamental physical parameters of the star. We have found four frequencies which correspond to gravity modes with az…
The pulsations of the B5IVe star HD 181231 observed with CoRoT and ground-based spectroscopy
International audience; Context: HD 181231 is a B5IVe star, which has been observed with the CoRoT satellite during ~5 consecutive months and simultaneously from the ground in spectroscopy and spectropolarimetry. Aims: By analysing these data, we aim to detect and characterize as many pulsation frequencies as possible, to search for the presence of beating effects possibly at the origin of the Be phenomenon. Our results will also provide a basis for seismic modelling. Methods: The fundamental parameters of the star are determined from spectral fitting and from the study of the circumstellar emission. The CoRoT photometric data and ground-based spectroscopy are analysed using several Fourier…