red giants tagged posts

The MAGIC telescopes have observed the nova RS Ophiuchi shining brightly in gamma rays at extremely high energy. The Gamma rays emanate from protons that are accelerated to very high energies in the shock front following the explosion. This suggests that novae are also a source of the ubiquitous cosmic radiation in the universe which consists mainly of protons rich in energy, which race through space at almost the speed of light.

Light on, light off — this is how one could describe the behavior of the nova, which goes by the name RS Ophiuchi (RS Oph)...

About eight percent of red giants are covered by sunspot-like, dark areas; these stars rotate faster than others of their kind. Starspots are more common among red giant stars than previously thought. Astronomers report that approximately eight percent of red giants exhibit such spots. Although red giants are generally regarded as slowly rotating stars, those with starspots are apparently an exception. The new publication offers a comprehensive analysis of the reasons for their short rotation periods.

Among the Sun’s most striking features are its sunspots, relatively darker areas compared to the rest of the surface, some of which are visible from Earth even without magnification...

Some of the Earth’s building material was stardust from red giants. Astronomers can also explain why the Earth contains more of this stardust than the asteroids or the planet Mars, which are farther from the sun.

Around 4.5 billion years ago, an interstellar molecular cloud collapsed. At its centre, the Sun was formed; around that, a disc of gas and dust appeared, out of which the earth and the other planets would form. This thoroughly mixed interstellar material included exotic grains of dust: “Stardust that had formed around other suns,” explains Maria Schoenbaechler, a professor at the Institute of Geochemistry and Petrology at ETH Zurich...

A sequence of snapshots from a simulation showing a red giant star tunneling through a high density gas clump. The star is moving downward in the illustration, as indicated by the bow-shaped “onion skin” surfaces of constant density. Soon after the star plunges into the clump, it develops a high temperature “blister” at the point of impact and a full turbulent wake behind it. Credit: Georgia Tech

Why is the center of the Milky Way filled with young stars but has very few old ones. According to the theory, the remnants of older, red giant stars are still there – they just aren’t bright enough to be detected with telescopes...