The familiar star in the middle of our solar system has had billions of years to develop and finally provide us life-giving energy on Earth. But our Sun was a developing baby star a very long time ago. When the Sun was so young, what did it look like? It's been for a long time a riddle that might teach us the creation of our solar system, so-called sol as the Latin word for Sun, and other stellar systems consisting of planets and cosmic objects circling stars.



"We have discovered hundreds of planets in our galaxy in other star systems, but where did all of these planets originate from? From whence did the Earth come? That's what motivates me, really, "Says Catherine Espaillat, the principal author of the study and associate professor of astronomy at the University of Boston.



A recent study article by Espaillat and colleagues published in Nature offers fresh clues regarding what forces played when our Sun was early in its life. For the first time, it detects a distinctive baby star spot, which gives new information on how newborn stars develop.



When a newborn star forms, says Espaillat, it consumes dust and gas particles surrounding it in a so-called protoplanetary disc. In a process termed accretion, the particles smash into the surface of the star.



"This is the same sun-filled procedure," said Espaillat.

Protoplanetary disks are discovered inside magnetized molecular clouds, a reproductive base for creating new stars recognized across the cosmos by astronomers. It was theoretically assumed that the protoplanetary disks and stars have a magnetic field linked and that the particles are following the area to the lead. As particles crash on the expanding star surface, hot spots – scorching and dense — develop at the focal points of the accretion process.

Taking a young star approximately 450 million light-years distant from the Earth, Espaillat and the observations of their Team validate, for the first time, the precise accretion models established by astronomers to forecast the development of hot spots. Until now, these computer models have depended on methods that compute how the magnetic field structures guide particles from protoplanetary disks to fall into particular locations on the surface of developing stars. Observable data now supports these computations.



The Team of the BU, comprising John Wendeborn, a graduate student, and Thanawuth Thanathibodee, a postdoctoral researcher, examined attentively the young Star GM Aur situated in the Taurus-Auriga molecular cloud of the Milky Way. The surface of a far-away star is not presently feasible to picture, Espaillat adds. Still, other photographs are conceivable since some areas of the surface produce light at different wavelengths. The Team has taken a weekly snapshot of light wavelengths from the surface of GM Aur, making X-ray, ultraviolet (UV), infrasound, and visible light information. Their GM Aur sights relied on the 'eyes of NASA's Hubble Space Telescope, TESS, Swift Observatory, and the Las Cumbres World Telescope Network.

This specific star, GM Aur, is turning in approximately a week, and the levels of luminosity are anticipated to peak and fade when the hot spot moves from the Earth and returns to face our planet once again. But when the Team initially set their data together, they were stunned by what they observed.



"We noticed a day's offset [in the data]," adds Espaillat. Instead of every light wavelength peaking at the exact moment, approximately 1 day before every other wavelength reached its peak, UV light was most vital. At first, they believed they might have collected incorrect information.



"We have gone over the data so many times, verified the timing twice, and concluded it wasn't a mistake." They found that the hot spot itself is not entirely uniform, and it contains a much hotter region than the rest.

"The hot spot is not a complete circle...



This's more like a bow with the hotter and denser portion of the bow than the rest, "Espaillat adds. He says. The distinctive form explains the error in the light wavelength measurement. This is a phenomenon never before observed in a hot area.



"This [research] tells us that the hot areas are the stellar surface imprints of the magnetic field," adds Espaillat. At one time, the Sun also had hot springs—different from subfields that are colder than the rest of its surface—concentrated in the regions in which particles were eaten from a protoplanetary gas and dust disk around it.



Eventually, protoplanetary disks evaporate away and leave stars, planets, and other cosmic objects that form a stellar system behind Espaillat. There is still proof that our solar system was fuelled by the protoplanetary disc, she said, found in our asteroid belt and all the planets. Espaillat believes the study of young stars sharing comparable characteristics with our Sun is crucial to our own planet's formation.