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.
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.
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.
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.
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.
Astronomers have found a white dwarf that was once two white dwarfs. The pair of stars merged into one about 1.3 billion years ago. The resulting star, named WDJ0551+4135, is about 150 light years away.
The star V Sagittae is the next candidate to explode in stellar pyrotechnics, and a team of astronomers set the year for that cataclysmic explosion at 2083, or thereabouts. V Sagittae is in the constellation Sagitta (latin for arrow,) a dim and barely discernible constellation in the northern sky. V Sagittae is about 1100 light years from Earth.
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.