Brown dwarfs are stars that are "halfway" between what is considered a planet and the astronomical objects commonly called stars.
A brown dwarf is a fascinating substellar object that, due to the characteristics it presents, does not fit within the group of gas giant planets nor does it fit the profile of stars . This type of star incapable of nuclear fusion is constantly being investigated in order to obtain greater details about its composition, structure, behavior and other curiosities.
Through the James Webb Space Telescope , for example, it has been possible to detect a tiny brown dwarf that remains floating freely without orbiting bodies. It is considered to be, at least for the moment, the smallest of the celestial elements that can arise in the appearance of a star . Its mass is just three times that of Jupiter .
Another study has paid special attention to the orbital inclination with the aim of establishing whether the brown dwarf is born as a star (when a molecular cloud fragments and experiences a gravitational collapse) or can develop as a planet . According to astronomical experts, like certain exoplanets , each brown dwarf can have an orbit inclined to different degrees depending on the rotation orientation of its host star. Astronomers who worked on the subject point out that a brown dwarf probably began as a star if it is at a considerable distance from its companion and has a high orbital inclination, while a short separation and a low orbital inclination are interpreted as indications of a birth as a planet within a circumstellar disk .
Characteristics of a brown dwarf
By observing and examining brown dwarfs (also called failed stars ), researchers record data related to their temperature, luminosity, composition and rotation to appreciate their particularities.
It has been determined that no nuclear reactions develop inside it, that its mass is low and that its size is somewhere between the dimensions of a planet like Jupiter and those of a small star .
Although they emit little energy and, therefore, it is difficult to see them directly from a great distance, so far it has been possible to identify numerous brown dwarfs whose surface temperatures range between 800 and 2000 degrees Celsius .
They lack the resources to complete the hydrogen fusion that keeps stars bright and at a high temperature for long periods of time, which is why the so-called brown dwarfs gradually cool and contract.
Brown dwarfs, disks, stars and other celestial objects have been discovered in the Orion Nebula with the James Webb Telescope.
Detection, observation and classification
The detection, observation and classification tasks of brown dwarfs are useful because, for example, they give the possibility of knowing what and what these objects are like, in addition to finding out whether or not they are uniformly distributed near our solar system .
By emitting heat as infrared light , these stellar bodies are detected by telescopes .
Using the Keck telescope , to cite a specific case, a team of scientists found, by chance, a very special brown dwarf that ended up receiving, informally, the name The Accident . What stands out is its age (it could be an object between ten thousand and thirteen billion years old), its level of cold and its unusual brightness (in certain wavelengths it radiates a fragile light and in other areas it shines brighter). A NASA observatory , the Spitzer Space Telescope , was also used to combine knowledge, incorporate recent data and, with all this wealth of information, make a three-dimensional map of more than five hundred brown dwarfs and take advantage of everything that is being discovered. about them to, given the similarities they have with exoplanets , obtain greater precision about the planets that orbit stars outside our solar system .
To date, several types of brown dwarfs have been discovered. Based on the spectral parameter , Y, T, L and M type brown dwarfs are differentiated. In the first case (the Y brown dwarfs ) the temperatures are low, while the T and L varieties exhibit an atmospheric temperature that exceeds 900 degrees Celsius.
A modern radio telescope of Australian origin, known as SKA Pathfinder , meanwhile, was essential in locating the coldest of the brown dwarfs identified so far.
Astronomers have been able to observe a brown dwarf separated by approximately two million kilometers from a fast neutron star called a pulsar whose radiation significantly raises the temperature of one of the sides of the aforementioned brown dwarf.
Brown dwarfs and varieties of stars
Just as there are challenges, research projects and mysteries focused on brown dwarfs , scientific work that emphasizes other objects and questions that allow us to decipher more and better the universe is also essential.
In this context, it is enriching to learn that a sub-brown dwarf does not become so massive as to undergo the deuterium fusion process nor does it achieve the minimum percentage of mass to be part of the group of brown dwarfs .
It has been determined, on the other hand, that there is a brown dwarf that apparently survived after being devoured by a giant star , whose mass is intermediate or low, which falls into the category of red giant .
Likewise, in recent seasons a white dwarf capable of burning helium has been found and a theory has gained strength indicating that, in a very long time, when everything has died in the universe, there could be white dwarfs capable of, in an environment of absolute darkness , explode in supernovas . As is evident, astronomy has advanced and continues to evolve, although unknowns, speculations, missions and explorations remain and grow due to the desire and need of human beings to educate ourselves about the Milky Way and the afterlife.