Pre-Main Sequence stars (which are still contracting and whose nucleus is still not hot and dense enough to ignite the nuclear fusion) are often observed surrounded by a disc of gas and dust called protoplanetary discs. Among the reasons why it is crucial to study these discs, it must be cited the fact that they are the environment of planet
Pre-Main Sequence stars are young stars (solar type pre-main sequence stars are younger than about 30 million years), that are often observed surrounded by a disc of haas and dust called “protoplanetary discs”. These discs can actively accreting matter onto the central star, with a complex process resulting from a complicated interplay between the gas of the disc and the
Not all the archaeologists do their studies digging holes or classifying artifacts in dusty museums… some of them actually use telescopes… Galactic archeology is a branch of astronomy dedicated to the study of the formation and evolution of the components of our Galaxy (bulge, bar, disc and halo) by analyzing ages, dynamics, and chemical abundances of stars. Not an easy
The family of the potentially habitable exoplanets named “super-Earths” (rocky planets with a mass ranging between 2 and 10 times that of the Earth), counts a brand new member. On Astronomy & Astrophysics has been recently published the study “HADES RV Programme with HARPS-N at TNG. V: A super-Earth on the inner edge of the habitable zone of the
An observation in X-rays of a single star 15 years long…The objective? The understanding of the coronal cycle in stars: do solar-like stars have a coronal cycle such as the one of our Sun? The term “solar activity” includes all those phenomena observed in the solar photosphere, chromosphere, and corona related to the solar magnetic field, such as sunspots,
A recent press release has appeared on the NASA/Chandra website (link), dedicated to the binary system V745 Sco and the model developed by S. Orlando (INAF-Astronomical Observatory of Palermo), M. Miceli (University of Palermo) e J. J. Drake (Harvard-Smithsonian Center for Astrophysics, US), which explains the nova explosion occurred on February 6th 2014. V745 Sco is a binary system composed
Star forming regions are complex environments, shaped by the star formation process (which involves gravity, turbulence and magnetic fields) and the interaction between the clouds and the stellar winds and energetic radiation (X-ray and UV) produced by the newborn stars. The interaction between clouds and stellar wind and radiation is of particular interest. Stellar radiation creates expanding fronts in
Stars more massive than 9 solar masses are efficient chemical labs, where hydrogen and helium are synthesized into other chemical elements, such as oxygen, carbon, and silicon. When these stars explode as supernovae (type I or “core-collpase” supernovae), these chemical elements are ejected into space, enriching the interstellar medium and being in future available to form new generations of stars.
The life cycle of very massive stars ends in supernovae explosions. During these violent phenomena, an amount of energy similar to that produced by the Sun during its entire lifetime,more than 10 billion years long, is released in few seconds. Besides, the atmosphere of the exploding star (the progenitor star) is ejected with a velocity in excess of 1000 km/sec.
Conservation of angular momentum is one of the fundamental laws of physic that every student must deal with. Let’s make an example: if we consider a rotating cloud of dust and gas of our Galaxy and we let it collapse under its own gravity, and then form stars, the conservation of its angular momentum dictates a faster and faster rotation
