The most energetic explosions in the Universe come from stars called supernovae. These galactic bombs have the energy of about 1028 mega-tons. After they detonate, the only thing left behind is either a neutron star or black hole. Another type of stellar explosion is known as a nova which has much less energy and covers the surface of a white dwarf.
Now, a team of astronomers recently discovered a new type of stellar explosion akin to supernovae and novae but with much less energy, and they’re calling it a micronova.
Black holes don’t emit light, which makes them difficult to study. Fortunately, many black holes are loud eaters. As they consume nearby matter, surrounding material is superheated. As a result, the material can glow intensely, or be thrown away from the black hole as relativistic jets. By studying the light from this material we can study black holes. And as a recent study shows, we can even determine their size.
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.
Binary star systems are everywhere. They make up a huge percentage of all known solar systems: from what we can tell, about half of all Sun-like stars have a binary partner. But we haven’t really had a chance to study them in detail yet. That’s about to change. Using data from the European Space Agency’s Gaia spacecraft, a research team has just compiled a gigantic new catalog of nearby binary star systems, and it shows that at least 1.3 million of them exist within 3000 light-years of Earth.
The Big Bang produced the Universe’s hydrogen, helium, and a little lithium. Since then, it’s been up to stars (for the most part) to forge the rest of the elements, including the matter that you and I are made of. Stars are the nuclear forges responsible for creating most of the elements. But when it comes to lithium, there’s some uncertainty.
A new study shows where much of the lithium in our Solar System and our galaxy comes from: a type of stellar explosion called classical novae.
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.
The theory of general relativity is packed with strange predictions about how space and time are affected by massive bodies. Everything from gravitational waves to the lensing of light by dark matter. But one of the oddest predictions is an effect known as frame-dragging. The effect is so subtle it was first measured just a decade ago. Now astronomers have measured the effect around a white dwarf, and it tells us how some supernovae occur.
Astronomers have discovered a large Neptune-sized planet orbiting a white dwarf star. The planet is four times bigger than the star, and the white dwarf appears to be slowly destroying the planet: the heat from the white dwarf is evaporating material from the planet’s atmosphere, forming a comet-like tail.
When a star reaches the end of its life cycle, it will blow off its outer layers in a fiery explosion known as a supernova. Where less massive stars are concerned, a white dwarf is what will be left behind. Similarly, any planets that once orbited the star will also have their outer layers blown off by the violent burst, leaving behind the cores behind.
For decades, scientists have been able to detect these planetary remnants by looking for the radio waves that are generated through their interactions with the white dwarf’s magnetic field. According to new research by a pair of researchers, these “radio-loud” planetary cores will continue to broadcast radio signals for up to a billion years after their stars have died, making them detectable from Earth.
Stars live and die on epic time scales. Tens of millions of years, hundreds of millions of years, even billions of years or longer. Maybe the only thing that surpasses that epicness is when two dead stars join together and come back to life.