Science Desk, Dec 13 (EFE).- The James Webb Space Telescope has identified the smallest free-floating brown dwarf star about 1.000 light-years away. According to the Astronomical Journal, this discovery may help answer the question of how small stars are formed.
Brown dwarfs are sometimes called failed stars. They form through gravitational collapse but never gain enough mass to initiate nuclear fusion.
The James Webb-discovered star, located in the star cluster IC 348 about 1.000 light-years away in the Perseus star-forming region, is only three to four times the mass of Jupiter.
In the search for the smallest brown dwarf, researchers Kevin Luhman of the Pennsylvania State University, and Cartarina Alves de Oliveira of the European Space Agency looked for a young cluster, only about five million years old, so any brown dwarf would still be relatively bright in the infrared due to the heat of its formation.
Webb’s infrared sensitivity was crucial because it allowed them to detect fainter objects than the ground-based telescopes. They selected three objects, each weighing between three and eight Jupiter masses, with surface temperatures ranging from 830 to 1.500 degrees Celsius.
According to computer models, the smallest of these objects is only three to four times the mass of Jupiter.
Tiny brown dwarfs not only help explain how stars form but can also help astronomers understand exoplanets.
These less massive stars overlap with larger exoplanets, so they would be expected to have similar properties.
However, it is easier to study a free-floating brown dwarf than a giant exoplanet, since the latter is hidden behind the glow of its host star.
Two of the brown dwarfs identified in this study show the spectral signature of an unidentified hydrocarbon, a molecule containing hydrogen and carbon atoms.
“This is the first time we’ve detected this molecule in the atmosphere of an object outside our solar system,” explained Alves de Oliveira.
“Models for brown dwarf atmospheres don’t predict its existence. We’re looking at objects with younger ages and lower masses than we ever have before, and we’re seeing something new and unexpected,” she added. EFE
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