The authors of the work stated that three of these fastest brown dwarfs will, after some time, approach the rotation speed limit for all brown dwarfs, and then decay.
These three dwarfs are roughly the same diameter as Jupiter, but 40 to 70 times more massive. The fastest rotates around its axis once an hour, for comparison, Jupiter makes a revolution every 10 hours. Based on their size, this means that the largest brown dwarf rotates at a speed of 100 km per second, or 360 thousand km per hour.
Since brown dwarfs cool with age, the temperature difference suggests that these brown dwarfs have different numbers of years. Before a rotating object falls apart, it usually becomes flatter as it deforms under pressure.
Given that brown dwarfs tend to accelerate with age, scientists still don’t know if they often exceed their rotational speed limit and fall apart? For example, other stars have natural inhibitory mechanisms that keep them from collapsing. It is not yet clear whether similar mechanisms exist in brown dwarfs.
The maximum rotational speed of any object is determined not only by its total mass but also by how this mass is distributed. Therefore, it is important to understand the internal structure of a brown dwarf: the material inside it is likely to shift and deform in such a way that it can change the speed of rotation of the object. Like gaseous planets such as Jupiter and Saturn, brown dwarfs are composed primarily of hydrogen and helium.
Physicists use observation, laboratory data, and mathematics to create models of how brown dwarfs should look inside and how they will behave in extreme conditions. But current models show that the brown dwarf’s maximum rotational speed should be about 50-80% faster than the hourly rotation period described in the new study.
Scientists continue their work on this topic.