Presentate stime delle proprietà fisiche delle stelle M che saranno osservate dal satellite PLATO Tra pochi mesi la scienza esoplanetaria potrà contare su un nuovo e potente strumento: il satellite dell’Agenzia Spaziale Europea PLATO (PLAnetary Transits and Oscillations of stars), il cui lancio è previsto per gli inizi del 2027. PLATO è progettato per la ricerca di esopianeti attorno
Grazie all’analisi dettagliata delle osservazioni ottenute con il satellite TESS della NASA, capace di produrre curve di luce stabili e ad altissima precisione (una curva di luce rappresenta la variabilità temporale dell’intensità della radiazione emessa da una sorgente), è stato possibile osservare per la prima volta delle oscillazioni quasi-periodiche, con un periodo di 70-100 minuti, nella stella di classe spettrale
L’emissione ad alta energia da parte delle stelle può avere un impatto importante sulle atmosfere dei pianeti. Per comprendere questo effetto a fondo, è necessario tenere conto di come questa emissione varia nel tempo. Negli ultimi anni, le stelle di piccola massa di classe spettrale M hanno assunto una notevole importanza nella ricerca e caratterizzazione degli esopianeti. Questo perché
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
M dwarf stars, with temperature ranging between 2400 and 3900 K and mass between 0.08 and 0.7 solar masses, are ideal targets for the search of exoplanets. This because the most important techniques to search for exoplanets are more effective when applied to stars of this spectral type than to more massive stars. For instance, the method of radial velocity
In the last years, stars of spectral class M (which are stars with effective temperatures between 2400 and 3700 K and masses between 0.08 and 0.45 solar masses) have been extensively observed for the search of exoplanets. This both because they are the most abundant class of stars in the Galaxy, and because the low star/planet mass ratio, compared to
The mechanisms involved in the formation of planets are still not completely understood. The most widely accepted model that describe the formation of gaseous planets is the core-accretion model. In this paradigm, the formation of these planets starts with the formation of a large rocky core by the coagulation of planetesimals, followed by the accretion of a large gaseous envelope
Despite theoretical models predict a large abundance of Earth-like planets in our Galaxy, the family of the 4284 planets discovered so far (updated at 2020/9/25, credits: NASA) counts relatively a few of such a planets. This is clearly an observational bias, due to the fact that the methods used to detect planets are not sensitive to small planets. For this
Stellar X-ray emission arises from their corona, which is the outer part of stellar atmosphere with low-density high-temperature (up to million degrees) plasma. Even if we lack a fully understanding of the details, we know that the intensity of stellar X-ray emission depends on the intensity and the morphology of stellar magnetic field. The interior of stars of FGK
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
