Get ready for a mind-boggling cosmic mystery! The James Webb Space Telescope has stumbled upon a fascinating phenomenon in a star-forming region called Ophiuchus. Astronomers have detected high-energy ultraviolet radiation around five infant stars, or protostars, and this discovery might just shake up our understanding of how stars are born.
Protostars are the newborn babies of the star family, formed from the collapse of dense gas and dust clouds. These little stars are still surrounded by the material from which they were born, and they continue to grow by gathering more mass. But here's where it gets controversial: these young stars, which shouldn't be capable of producing radiation, are emitting powerful ultraviolet rays.
Agata Karska, a researcher from Poland, puts it simply: "Young stars are not supposed to be a source of radiation. So, we shouldn't expect it. Yet, we've found UV near protostars." This unexpected finding has sparked a scientific investigation to uncover the source of this radiation.
The team aimed the mighty James Webb Space Telescope (JWST) and its Mid-Infrared Instrument (MIRI) at the Ophiuchus molecular cloud, which is teeming with hot, massive stars. By observing five protostars at different distances from these giants, the scientists focused on molecular hydrogen emissions.
Molecular hydrogen, composed of two hydrogen atoms, is the most common molecule in the universe. However, detecting it from Earth is tricky due to our atmosphere, and even from space, it's challenging because the gas in molecular clouds is too cold to excite these molecules. But when outflows from young stars collide with surrounding clouds, shockwaves heat the matter, causing molecular hydrogen to emit distinctive signals that JWST and MIRI can detect.
So, where is this ultraviolet radiation coming from? One theory suggests it's from processes happening around the protostars themselves, like shocks from material falling onto them. Another idea is that the radiation is generated by shocks along the jets erupting from these temperamental infant stars. Or, could it be that nearby massive stars are shining their light on their protostar neighbors?
To investigate, the team considered the properties of the surrounding stars and their distances to the protostars. They also accounted for the dust around the protostars, which can absorb ultraviolet radiation and re-emit it at longer wavelengths. Using these methods, the researchers found that the ultraviolet radiation varied significantly between the protostars, which should have resulted in differences in molecular emissions. But they didn't see those differences.
This led the team to reject external sources like neighboring stars as the origin of the radiation. "We can say with certainty that UV radiation is present near the protostar and affects the observed molecular lines. Therefore, its origin must be internal," Karska concluded.
The researchers will continue to study JWST observations of the gas, protostars, dust, and ice in the Ophiuchus molecular cloud to unravel the mystery of this unexplained ultraviolet radiation.
This groundbreaking research was published on November 13 in the journal Astronomy & Astrophysics, challenging our understanding of star formation and leaving us with a tantalizing question: What other cosmic surprises await us as we explore the universe with advanced telescopes like JWST?
