The galaxy is littered with white dwarfs, the burnt out remnants of stars that have run out of hydrogen fuel in their cores, but were too small to explode as supernovae. But far from being lifeless orbs, around a tenth of white dwarfs have powerful magnetic fields, a million times stronger than that of the Sun. How did these magnetic white dwarfs become such strong magnets? And just how many are there. The authors of this paper set out to answer the second of these questions, in the hope that it would shed light on the first.
While the Sun is an excellent starting point in a quest to understand magnetism, the authors of today’s paper want more. They take advantage of something only relatively cool stars can have in their atmospheres to study magnetic fields: molecules in starspots.
The orbits of some recently discovered exoplanets seem to be synchronised with the rotation of their host stars. Can this mystery be explained?
Transit observations can yield a lot of information about exoplanets. If a transiting exoplanet encounters stellar wind, the bow shock created can show up in the transit light curves. In this paper, the authors investigate how the stellar wind of a star can shape the light curves we observe.
Astronomers love to ignore magnetic fields. But they may strongly affect the pattern of atmospheric circulation in hot Jupiters.