This Moon-Sized White Dwarf Star Is The Smallest Ever Found!

Within the Milky Way galaxy, it is estimated that between 100 billion and 400 billion stars exist, and astronomers have recently announced that they may have discovered one of the smallest of them. A white dwarf star that is of a similar size to the moon, yet is heavier than the sun. You're watching V101 Science, and this is your Space Fix. Dubbed the Very Special Star by some, this white dwarf has a mass greater than that of the sun, all compressed into a body that is slightly bigger than the moon, making it the most massive white dwarf known, but also the smallest. White dwarfs are usually about the size of Earth, and are cool, dim cores of long dead stars that have exhausted their fuel and shed their outer layers into space. About 97% of all stars will ultimately become white dwarfs at the end of their lives. The sun, for example, will one day share the same fate, and evolve into one of these smouldering corpses in around 5 to 10 billion years from now. This particular dead star is named ZTF J1901-1458, and is located around 130 light years away in the constellation of Aquila. Its diameter is much smaller than the Earth's however, at only 2,670 miles, or 4,296 kilometers, yet crammed into this moon-sized space is 1.35 times the mass of the sun. Scientists are not 100% certain how this rare star formed, but it does appear that it was created from two ancient stars that likely grew old together and exhausted their fuel supplies, before evolving into white dwarfs. Over time, the pair spiralled closer and closer, until they ultimately merged, becoming one. If the parent stars had too much mass, then they would have exploded in what is called a Type 1a supernova. However, it seems that in this case, they didn't. Instead, they came together, creating the most massive of all the white dwarfs discovered so far, likely because they were both below a certain mass threshold. This process of merging causes the rare white dwarf to inherit its parent's combined spin speed, resulting in the unusual star rotating on its axis at a violent pace, around one revolution every 7 minutes. As an example, the sun takes 27 days to complete just one rotation. This rapid spin also helps boost its intense magnetic field, which is nearly 1 billion times stronger than the sun's. It may be small, but this white dwarf is immensely powerful. It was discovered using a host of telescopes that helped analyze the dead star, but it was initially spotted by the Zewiki Transient Facility at the Palomar Observatory in California, which is a telescope that scans the entire northern sky every two nights, looking for cosmic bodies that blink, move, or change in brightness. So what will become of this bizarre white dwarf? Well, the so-called Very Special Star could be on the verge of collapse. Researchers think that the star has enough mass to possibly evolve into an even smaller, even denser object, called a neutron star. Neutron stars typically form when a star much more massive than the sun explodes as a supernova, leaving behind a tiny, super-dense object. They can range from 1.4 times the mass of the sun up to about twice as much, all of which is squeezed into a star that's only around 12 miles or 20 kilometers across, or about the size of a city. One tablespoon of a star like this would weigh more than a billion tons here on Earth. If the hypothesis is correct, and this newly found small but massive white dwarf is on the collapsing even further and becoming one of these bizarre objects, then this could mean that many other neutron stars throughout the universe formed in this previously unknown way. However, just like all new scientific discoveries, more questions are raised than answered, and so we will have to wait until further studies have been completed before we can really start to understand the smallest, yet most massive white dwarf star discovered so far. So what did you think of this bizarre dead star? Let me know in the comments section below. If you enjoyed this episode of Space Fix, then remember to tap the like button, and subscribe if you haven't already, there is plenty more to come. Thank you so much for watching, and I'll see you all next time.