Do you remember the claim that Jupiter is somehow a failed star? Well, this time it seems we have finally found a star that behaves in the same way, storms included. Have a look at what NASA has published just yesterday. The image is worth more than any explanation.
It looks like our Jupiter but it’s W1906+40, discovered in 2011 during NASA’s Wide-field Infrared Survey Explorer. Its overall size is the same and the storms are roughly as big as Jupiter’s Great Red Spot (here for the whole article). Intriguing, isn’t it?
As explained by the scientists at NASA, this pretty one “belongs to a thermally cool class of objects called L-dwarfs. Some L-dwarfs are considered stars because they fuse atoms and generate light, as our sun does, while others, called brown dwarfs, are known as “failed stars” for their lack of atomic fusion. The L-dwarf in the study, W1906+40, is thought to be a star based on estimates of its age (the older the L-dwarf, the more likely it is a star). Its temperature is about 3,500 degrees Fahrenheit (2,200 Kelvin). That may sound scorching hot, but as far as stars go, it is relatively cool. Cool enough, in fact, for clouds to form in its atmosphere.”
One may ask what is the difference between a brown dwarf and a gas giant then, considering that gas giants like Jupiters are considered too failed stars. The reasons is not, or not only, size, or even composition (are all made of hydrogen and helium, after all) but the way they have formed.
“Nearly all scientists who study the formation of planets believe that Jupiter formed in a very different manner than stars form, so that calling Jupiter a ‘failed star’ is misleading. Stars form directly from the collapse of dense clouds of interstellar gas and dust. Because of rotation, these clouds form flattened disks that surround the central, growing stars. After the star has nearly reached its final mass, by accreting gas from the disk, the leftover matter in the disk is free to form planets. Jupiter is generally believed to have formed in a two-step process. First, a vast swarm of ice and rock ‘planetesimals’ formed. These comet-sized bodies collided and accumulated into ever-larger planetary embryos. Once an embryo became about as massive as ten Earths, its self-gravity became strong enough to pull in gas directly from the disk. During this second step, the proto-Jupiter gained most of its present mass (a total of 318 times the mass of the Earth). Soon thereafter, the disk gas was removed by the intense early solar wind, before Saturn could grow to a similar size.” (Alan P. Boss, Carnegie Institution of Washington, in an article of Scientific American).
So, even though brown dwarfs sometimes look identical to planets they were still born like stars– so from an original gas cloud and not in the protoplanetary disk that surrounds a star.
Is it possible instead for a gas giant like Jupiter becomes a star somewhere in the future – say, a brown star? Unlikely, sure, but have a look at this video, from Universe Today.
Thank you for this… what a fascinating article!
Thanks! 😀