T Tauri stars are young low-mass stars (typically younger than 5 million of years), which are surrounded by a protoplanetary disk, e.g. a disk of gas and dust orbiting around the star. The disk material does not reach the central star: the dust component sublimates in the inner disk, where the temperature exceeds 1500 degrees, while the gas disk is truncated
Several fields in modern astronomy rely on high-precision photometric data. This is true, in particular, for the search of exoplanets with the method of transits. This method consists in searching very small periodic dimming of stellar emission due to the transit of planets along the line of sight during their orbits. For instance, the transit due to a Hot Jupiter (a gaseous
The discovery of the first exoplanet in 1995 was a challenge to our knowledge of the architecture of planetary systems. The planet orbiting around the star 51 Peg, in fact, was different than the planets in our Solar System: it was a gaseous giant orbiting at only 0.05 Astronomical Units (A.U., where 1 A.U. is the average distance between Earth
On June 2019, the panel for the evaluation of the proposals for observations with the NASA telescope Chandra, operating in the X-rays, which met up in Boston, has approved the Large Project: “Star formation in starburst: a deep ACIS-I observation of Westerlund 1“, led by the astronomer Mario Giuseppe Guarcello – INAF Astronomical Observatory of Palermo. More details on the
Hot Jupiters are gaseous planets orbiting very close to their stars, typically closer than 0.1 Astronomical Units (the average distance between Earth and Sun), and with very short orbital periods of days or even hours. An extreme sub-class of these planets are the ultra-Hot Jupiters. These planets are tidally-locked to their stars (which means that they show always the same
Supernove explosions are repeatedly observed in distant galaxies, which lie at such large distances that it is impossible for us to resolve the geometry of the ejected material and its interaction with the surrounding interstellar and circumstellar clouds. With the only exception of SN 1978A, in the Milky Way and in the nearby galaxies (namely the Magellanic Clouds), we did
The intensity of Solar magnetic activity and of the related phenomena (such as sunspots and flares) varies with an 11-years cycle. In order to understand whether such an activity cycle is common among solar-type stars, since 1966 a project based on the Observatory of Mt. Wilson is collecting measurements of the cromospheric activity of a large sample of low-mass stars
Some galaxies are more than 100 times brighter in the radio wavelengths than the other galaxies, being thus classified as “radio galaxies“. Images at high spatial resolution have shown that the radio emission in these sources arises mainly from two regions, called “radio lobes“, extended hundreds of light years and symmetric with respect to the center of the galaxy. The
Stars more massive than 9 solar masses end their evolution in spectacular supernova explosions. These explosions are triggered by the gravitational collapse of the core of such massive stars, once the thermonuclear reactions are exhausted and the core is not supported against gravity by the pressure produced by the reactions. Supernovae are not simple spherical explosions, but rather complex phenomena
