Tag: Gaia

A first homogeneous study on the dynamics of stellar clusters. The paper: “The Gaia-ESO Survey: 3D dynamics of young groups and clusters from GES and Gaia EDR3” of N. J. Wright (Keele University) recently appeared on MNRAS

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Stars do not form in isolation. During gravitational collapse, molecular clouds fragment, forming a large number of stars. For this reason, young stars are typically observed as members of star clusters or associations.   In the past decade, the study of stellar clusters in the Milky Way has undergone a revolution, thanks to observations from the Gaia satellite of the

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A study on the coronal activity in a complete sample of M stars nearby to the Sun. The paper: “Complete X-ray census of M dwarfs in the solar neighborhood. I. GJ 745 AB: Coronal-hole stars in the 10 pc sample” of M. Caramazza (Eberhard-Karls Universität Tübingen) appeared on A&A

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The corona is the outermost part of the atmosphere of the vast majority of stars, where the plasma is heated to millions of degrees by stellar magnetic activity. Since both the intensity and the topology of the stellar magnetic fields depend on the internal structure of stars, the study of coronal activity allows astronomers to better understand both the high-energy

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A new catalog of the Young Stellar Objects within 4500 light years based on Gaia/EDR3. The study: “Low mass young stars in the Milky Way unveiled by DBSCAN and Gaia EDR3. Mapping the star forming regions within 1.5 Kpc” of L. Prisinzano (INAF – OAPA) recently published by A&A

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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

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A large catalog of stars associated with stellar clusters recently compiled in the framework of the Gaia-ESO Survey.

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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

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Lithium abundance and stellar internal structure. The study: “The Gaia-ESO survey: Mixing processes in low-mass stars traced by lithium abundance in cluster and field stars” of L. Magrini (INAF – OA Arcetri) recently appeared on A&A

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The chemical history of Lithium abundance in the Universe is very complex. This chemical element has been first produced during the Big Bang, even if in very small quantities compared with hydrogen and helium. Since then, lithium is continuously created and destroyed by several processes occurring in stellar interior. This means that the lithium abundances we observe in stars today

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A comparison between different diagnostics of the age of stellar clusters. The study: “The Gaia-ESO survey: a lithium depletion boundary age for NGC 2232” of A. S. Binks (Keele University) recently appeared on MNRAS

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Measuring stellar ages is a difficult task but nevertheless very important. For instance, the study of stellar evolution requires accurate estimate of stellar ages. On the other hand, we can count on very few diagnostics that can allow astronomers to obtain reliable estimate of stellar ages, and typically these methods can be applied only to specific type of stars or

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Dynamic and expansion of stellar clusters. The study: “The Gaia-ESO Survey: asymmetric expansion of the Lagoon Nebula cluster NGC 6530 from GES and Gaia DR2” of N. J. Wright (Keele University) recently appeared on MNRAS

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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

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Formation and evolution of the Sco OB2 association. The study: “Stellar population of Sco OB2 revealed by Gaia DR2 data” of F. Damiani (INAF-OAPA) recently appeared on A&A

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OB associations have a rich population of massive stars (O and B stars), which are young and typically dispersed over large regions of the sky. While these massive stars can be easily recognized thanks to their intense luminosity, it is very hard to select the low mass stars belonging to OB associations. This because without evident stellar concentrations, these stars

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The chronology of star formation in NGC 6530. The study: “Wide-area photometric and astrometric (Gaia DR2) study of the young cluster NGC 6530” of F. Damiani (INAF-OAPA) recently appeared on A&A

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Stars form from the gravitational collapse of large interstellar clouds. During the process, the clouds fragment in smaller clouds, forming clusters and associations of stars counting from few tens to several hundred thousands stars. The star formation process typically is not a monolithic process, e.g. with a single large event of star formation occurring rapidly and forming all the stars

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Struttura ed evoluzione degli ammassi nell’associazione Vela OB2. Pubblicato su A&A: “The Gaia DR2 view of the Gamma Velorum cluster: resolving the 6D structure” di E. Franciosini (INAF-Arcetri)

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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

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