Astronomers from Cornell University have discovered a previously unknown object in our outer solar system using the most powerful radio telescope in the world, the Atacama Large Millimeter Submillimeter Array (ALMA).
The object, located in the direction of Alpha Centauri, the nearest star system to Earth (4 light years away), appears to be in the region of our outer solar system, which has enthusiasts hinting that it could be a planetary body. Scientists aren’t so quick to jump to conclusions.
ALMA first spotted the object in 2014 and follow up observations commenced in May 2015. Scientists suspected the object was a part of the Centauri system since it was discovered within the region. At that distance, the object would have to be a red dwarf star – but such a star should have been clearly visible in previous sky surveys. We should have saw it long ago.
With only two observations completed, its too early to be sure, but the object is likely closer and correspondingly smaller. Researchers think it may be an extreme trans-Neptunian object, likely smaller than Pluto, about 100 astronomical units (1 AU is roughly the distance from the Earth to the Sun) away from the Sun. That would make it the furthest known object in our solar system.
Another more exciting possibility is that it’s about 300 astronomical units away and about 1.5 times the size of Earth – making it the first Super-Earth object ever found beyond Pluto.
By observing the orbits of trans-Neptunian objects, astronomers have long hypothesized that there may be 1-2 Super-Earth type planets orbiting beyond Pluto. However, in this case there is reason for caution. Alpha Centauri is about 42 degrees away from our solar systems ecliptic. Most large solar system objects orbit within a few degrees of the ecliptic. It’s unlikely that a large planetary body has such an inclined orbit – so Planet-X conspirators may rest easy for now.
A third possibility is that it’s a cool brown dwarf about 20,000 astronomical units away. Such an object would be visible in sky surveys and rather easy to find given that the Centauri system is in our backyard and provides light.
There is still much to learn about the object and scientists stress that more observations need to be done before making any definitive conclusions. Whether dwarf planet, super-Earth or small star, its clear that something is lurking on the outer edge of our solar system.
Materials provided by Cornell University.