August 31st, 2014
Astronomers use models to derive properties of individual stars that we cannot directly observe, such as mass, age, and radius. This is also the case for a group of stars (a galaxy or a star cluster). One problem with current stellar population models is that they remain untested for old populations of stars. The authors of this paper devise a new way to test models of old stellar populations.
Sometimes, stellar evolution happens on more human timescales—tens to hundreds of years rather than millions or billions.
We have one canonical idea of what life looks like on Earth: nitrogen, water, carbon dioxide. But would this be true on another world? When looking for life in the atmospheres of exoplanets, we might want to consider searching for something completely different.
There are arguably a lot of things defy categorization, but it’s not everyday that we find something that suggests we do away with our categories altogether. The authors of today’s paper believe that the recently-discovered Type II supernova ASASSN-13co — read that as “assassin”, please — might just be one of the latter.
Over the past decade the study of planetary debris at white dwarfs has become an increasingly exciting area. Observations of this debris have allowed us to make unique discoveries about the chemical composition of extrasolar rocky planets, as well as revealing the endpoints of the evolution of planetary systems very similar to our own…
Simulations show that the Oort cloud contains eight billion asteroids (in addition to hundreds of billions of comets). Do these asteroids pose a threat to Earth?