With latest technologies and instruments, our ability to study the expanse of space far and beyond has increased greatly with more exoplanets being discovered every other day. However, there are a lot of space objects that lie close to the definition of a planet but not exactly one. An astrophysicist has recently introduced a new definition for what can be termed as “Planet”.
As stated by the International Astronomical Union, a ‘Planet’ is any celestial body that revolves in orbit around the Sun, carries sufficient mass for hydrostatic equilibrium resulting in a shape similar to round and last but not the least the body should have a clear surrounding close to its orbit. This definition is not applicable for the exoplanets as their orbit is around a star. Scientists have also found things that are outside the periphery of a solar system which might be an enormous planet or maybe a tiny star.
Planets do not have a fixed definition, just a simple working definition that has been written down by IAU Working Group on Extrasolar Planets in the year 2003. This particular working definition states that any object that has a size smaller than the star with a size enough in order to manufacture deuterium fusion is known as a brown dwarf which is neither a star nor a planet.
In words of Kevin Schlaufman, who is an astrophysicist at the Johns Hopkins University, the definition for a planet is very inconsistent as the burning of the deuterium is dependent upon the internal properties as well as the composition of an object. This proposal by Schlaufman was published in “The Astrophysical Journal” which suggests that taking a look at the surroundings of a celestial body can let us know about the formation of the same. This could be used to help distinguish between the planets and the brown dwarfs.
His paper also explained that if you look at the definition of the formation of planets, these masses of celestial bodies form via core accretion. Brown dwarfs, as well as stars, form via direct gravitational collapse which is either near the core scale or the disk. Regardless of the appeal shown by the definition, the same hasn’t been used practically due to the issues and difficulty in observing the origin of any celestial body that is orbiting at a great distance. In conclusion, any celestial object that holds a mass that is 10 times greater than Jupiter shall be considered as a brown dwarf and not a planet.