Nella struttura e nella dinamica del superammasso stellare Westerlund 1 potrebbe celarsi l’impronta della collisione con il piano della Via Lattea, avvenuta 2 milioni di anni fa. Gli ammassi stellari sono sistemi dinamici estremamente complessi e affascinanti. Cosa li rende così complicati? Innanzitutto, l’evoluzione sia dinamica sia fisica delle loro stelle. Stelle di massa diversa hanno tempi di vita
Berkeley 59 is a young stellar clusters, which is experiencing a rapid asymmetric expansion Stars typically form in groups or stellar clusters containing from hundreds to thousands of members. Within these clusters, stars are not stationary but move along trajectories determined by the system’s overall gravity (that is, the gravitational potential of the cluster) and by their mutual interactions.
The star-forming regions can differ significantly from one another, particularly in terms of the population of massive stars (with masses exceeding about 10 solar masses) and stellar density (defined as the number of stars per unit volume). These aspects can vary drastically from one region to another. Such differences are extremely important, as massive stars create environments dominated by high-energy
Spectroscopic observations of massive stars (i.e., those more massive than 8 solar masses) allow astronomers to study their rapid evolution, which occurs on much shorter timescales compared to solar mass stars, and the impact of parameters such as stellar rotation on their evolution. To achieve this, observations of stellar clusters are greatly valuable, as they are groups of stars formed
After their formation, during the first few million of years (how many? it depends on the mass: the larger the stellar mass the faster is their evolution) stars continue to contract under their the action of their own gravity, rising their temperature and density. During this phase, their nuclei have not started yet the thermonuclear reactions that will power the
Star clusters are a product of the star formation process. During their gravitational collapse, in fact, molecular clouds fragment forming hundreds or even thousands of stars. During the first few tens of million of years of their evolution, the young stars formed in a cloud are bound by the intense mutual gravitational attraction, forming a stellar cluster. Star clusters are important
Despite a significant fraction of stars form in stellar clusters counting hundreds to thousands of members, almost all the stars we observe today in the Milky Way is not associated to any stellar cluster. This occurs because newborn stellar clusters are typically dispersed in a few million of years by several intervening processes, such as the gravitational interaction among cluster
LSST (Large Synoptic Survey Telescope) is the future of the astronomy in the time domain. LSST is a new-generation telescope that will be built on Cerro Pachon in Chile (2700 meters). It will be equipped with a primary mirror of 8.4 meters of diameter and an innovative camera able to observe an very large field of view, more than 49
In the Milky Way one of the main modes of star formation is in stellar clusters, which remain associated with their parental cloud for about 5-10 million years. This makes the star forming regions complex targets, characterised by rich stellar populations packed into small regions, sometime even with massive stars, and clouds whose morphology and properties are affected by the
of Mario Giuseppe Guarcello ( follow mguarce) We are living a golden age for the research on stellar clusters and their structure, formation and evolution. This thanks to the satellite Gaia of the European Space Agency, which will provide position and radial velocity of over one billion stars with unprecedented precision, and the project Gaia-ESO Survey, an ambitious spectroscopic
