Found 4 talks width keyword early-type stars
The lowest metallicity stars that still exist today represent a window into the early Universe. Studying these stars gives us a local avenue to guide our understanding of star formation and supernova feedback in the early Universe, the early build-up of galaxies like our Milky Way, and the epoch of reionization. In this talk I will present recent results of the Pristine survey, a narrow-band photometric survey of the Milky Way designed to get metallicity information for millions of stars very efficiently. I will discuss what we have learned from our analysis of the most metal-poor stars about the early formation of the Milky Way. Moreover, I will highlight the bright future for this type of study in synergy with the upcoming highly-multiplexed spectroscopic surveys.
The field of Galactic archaeology has been very active in recent years, with a major influx of data from the Gaia satellite and large spectroscopic surveys. The major science questions in the field include Galactic structure and dynamics, the accretion history of the Milky Way, chemical tagging, and age-abundance relations. I will give an overview of GALAH as a large spectroscopic survey, and describe how it is complementary to other ongoing and future survey projects. I will also discuss recent science highlights from the GALAH team and compelling questions for future work.
AbstractGamma Dor stars (M = 1.2-2.5 M⊙; spectral type A-F) are very interesting from an asteroseismic point of view. They show gravity modes, which are the only modes that provide information on the deep stellar interior. Observationally they are very challenging targets. Typical pulsation periods are of the order of a day and amplitudes are fairly small (below 0.05 mag; 2 km/s), making it extremely difficult to monitor the periodic variations from the ground. The asteroseismic space missions CoRoT and Kepler are providing uninterrupted time-series from space, with unprecedented accuracy, and hence promise a revolution in the study of gamma Dor stars. I will present results of the seismic analysis of CoRoT and Kepler gamma Dor targets, and the associated ground-based support observations, involving many telescopes at different observatories (including La Palma and Izaña).
AbstractThe Orion star forming region is an ideal laboratory for many astrophysical studies. In this talk I will present a study of the chemical composition of early B-type stars in the Orion OB1 association. The main ideas I will talk about are: (1) The importance of self-consistent spectroscopic techniques for the abundance analysis in this type of stellar objects; (2) the study of the homogeneity of abundances in stars from the various stellar subgroups in OriOB1; (3) the comparison of O stellar abundances with recent Solar determinations; (4) the comparison of stellar abundances with those resulting from the analysis of the emission line spectra of the Orion nebula (M42); (5) the study of the oxygen depletion onto dust grains in the Orion nebula. La región de formación estelar de Orión es una laboratorio perfecto para muchos tipos de estudios en astrofísica. En esta charla me centraré en el estudio de abundancias de las estrellas de tipo B temprano presentes en la asociación OriOB1. Las principales ideas que presentaré son: (1) La importancia de los análisis espectroscópicos detallados en la determinación de abundancias en estrellas de tipo B temprano; (2) el estudio de la homogeneidad química de los distintos subgrupos estelares que componen OriOB1; (3) la comparación de la abundancias estelares de oxígeno con determinaciones recientes en el Sol; (4) La comparación de abundancias estelares con aquellas obtenidas a partir de análisis del espectro de M42, la nebulosa de Orion; (5) el estudio de la depleción de oxígeno en granos de polvo en la nebulosa de Orión.
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- 2022 Nobel Prize and the Challenges of Bell's Inequality: Closing the Freedom of Choice LoopholeDr. Amin BabazabehThursday November 30, 2023 - 10:30 GMT (Aula)
- TBDThursday December 14, 2023 - 10:30 GMT (Aula)