Is Jupiter a failed star?
Jupiter, we all know, is the largest planet in our solar system. According to the National Aeronautics and Space Administration (NASA) in the USA, it weighs 1.9 × 1027 kilograms and has a typical radius of 69,911 kilometres. In 1610, Italian astronomer, Galileo Galilei made the first detailed observation of the planet using a tiny telescope. Sometimes, Jupiter is described as 'failed star'. But what does this coinage mean? Is Jupiter a star that has failed? Let us find out.
What is a star?
Stars are huge spheres of scorching gas, mainly hydrogen and helium. But why are they so bright and hot? Nuclear fusion, which causes hydrogen to fuse with helium, makes the star extremely hot. It is the main source of energy for the star, giving it a bright appearance! The Sun is the nearest star to Earth. Most of the dots of light you see in the night sky are also stars. But there are several other stars so far from Earth that they can’t be spotted without a telescope.
Jupiter isn’t a star
Jupiter is called a failed star because it contains the same gases as the Sun (hydrogen and helium). However, it is not as big as the Sun. Jupiter is lightweight compared to the Sun. Its mass is around 0.1% that of the Sun. Therefore, it is incapable of causing the fusion of hydrogen to helium. The assumption that Jupiter is a 'failed star' arises from the lack of the necessary amount of mass to become a star. Although Jupiter is bigger than many small stars, it has not evolved into one. Why? Well, thermonuclear reactions (the fusion of hydrogen to helium) occur within the core of a celestial body and make it a star. Very high pressures and temperatures are required for these reactions to occur. Jupiter cannot become a star until it has a mass that is one thousand times more than its current mass. Thus, it is not the size, but the mass that is important to become a star. Jupiter is still a massive planet. When people refer to Jupiter as a failed star, they often mean that it has a similar abundance of hydrogen and helium as stars but doesn’t have the mass required to generate the internal pressures and temperatures needed to initiate a fusion process.
But, hypothetically speaking, what if Jupiter does become a star? The outcome will be a disruption of all the current orbits of the planet. The following events, in this case, might be unpredictable!
Failed stars: Do they exist?
Apart from Jupiter, are there celestial bodies with masses less than that of the Sun? Well, the answer is yes. They are known as red dwarfs. Only 7.5% of the solar mass (weight of the sun) is required to create a red dwarf. The smallest red dwarf is around 80 times more massive than Jupiter. In other words, you could create a star if you added 79 planets the size of Jupiter to our universe. One of the most common and smallest hydrogen-burning stars in the universe is known as the M dwarf or M-type star.
Are there any genuine failed stars, though? Yes, brown dwarf stars are true failed stars. The mass of these stars is generally 13 times that of Jupiter. But they lack the mass required to support the genuine fusion reaction that defines a star.