About 97% of all stars in our Universe are destined to end their lives as white dwarf stars, which represents the final stage in their evolution. Like neutron stars, white dwarfs form after stars have exhausted their nuclear fuel and undergo gravitational collapse, shedding their outer layers to become super-compact stellar remnants. This will be the fate of our Sun billions of years from now, which will swell up to become a red giant before losing its outer layers.
Unlike neutron stars, which result from more massive stars, white dwarfs were once about eight times the mass of our Sun or lighter. For scientists, the density and gravitational force of these objects is an opportunity to study the laws of physics under some of the most extreme conditions imaginable. According to new research led by researchers from Caltech, one such object has been found that is both the smallest and most massive white dwarf ever seen.
Continue reading “A Nearby White Dwarf Might be About to Collapse Into a Neutron Star”
White dwarfs have some surprisingly strong magnetic fields, and one team of astronomers may have finally found the reason why. When they cool, they can activate a dynamo mechanism similar to what powers the Earth’s magnetic field.
Continue reading “How can White Dwarfs Produce Such Powerful Magnetic Fields?”
Astronomers have developed a new technique to search for exoplanets – by looking for their crushed up bones in the atmospheres of white dwarfs. And it’s working.
Continue reading “White Dwarf Atmospheres Might Contain the Pulverized Crusts of Their Dead Planets”
A white dwarf isn’t your typical kind of star. While main sequence stars such as our Sun fuse nuclear material in their cores to keep themselves from collapsing under their own weight, white dwarfs use an effect known as quantum degeneracy. The quantum nature of electrons means that no two electrons can have the same quantum state. When you try to squeeze electrons into the same state, they exert a degeneracy pressure that keeps the white dwarf from collapsing.
Continue reading “Strange Green Star is the Result of a Merger Between two White Dwarfs”
The world we see around us is built around quarks. They form the nuclei of the atoms and molecules that comprise us and our world. While there are six types of quarks, regular matter contains only two: up quarks and down quarks. Protons contain two ups and a down, while neutrons contain two downs and an up. On Earth, the other four types are only seen when created in particle accelerators. But some of them could also appear naturally in dense objects such as neutron stars.
Continue reading “Is There a way to Detect Strange Quark Stars, Even Though They Look Almost Exactly Like White Dwarfs?”
Can the galaxy’s dead stars help us in our search for life? A group of researchers from Cornell University thinks so. They say that watching exoplanets transit in front of white dwarfs can tell us a lot about those planets.
It might even reveal signs of life.
Continue reading “James Webb Will Look for Signs of Life on Planets Orbiting Dead Stars”
The density of a white dwarf star defies our imagination. A spoonful of white dwarf matter would weigh as much as a car on Earth. Atoms within the star are squeezed so tightly that they are on the edge of collapse. Squeeze a white dwarf just a bit more, and it will collapse into a neutron star. And now, we can recreate the density of a white dwarf within a lab.
Continue reading “Scientists Recreate the Density of a White Dwarf in the Lab”
Supernovae are some of the most powerful events in the Universe. They’re extremely energetic, luminous explosions that can light up the sky. Astrophysicists have a pretty good idea how they work, and they’ve organized supernovae into two broad categories: they’re the end state for massive stars that explode near the end of their lives, or they’re white dwarfs that draw gas from a companion which triggers runaway fusion.
Now there might be a third type.
Continue reading “A Star had a Partial Supernova and Kicked Itself Into a High-Speed Journey Across the Milky Way”
Some very powerful telescopes will see first light in the near future. One of them is the long-awaited James Webb Space Telescope (JWST.) One of JWST’s roles—and the role of the other upcoming ‘scopes as well—is to look for biosignatures in the atmospheres of exoplanets. Now a new study is showing that finding those biosignatures on exoplanets that orbit white dwarf stars might give us our best chance to find them.
Continue reading “Rocky Planets Orbiting White Dwarf Stars Could be the Perfect Places to Search for Life”
About 570 light years from Earth lies WD 1145+017, a white dwarf star. In many respects it’s a typical white dwarf star. Its mass is about 0.6 solar masses, and its temperature is about 15,900 Kelvin. But five years ago, a team of astronomers wrote a paper on the white dwarf, showing that something unusual was going on.
Continue reading “Astronomers Watched a Star System Die”