Astronomers have made a groundbreaking discovery that could revolutionize our understanding of planet formation. Using the Atacama Large Millimeter/submillimeter Array (ALMA), they have found a planet-birthing disk surrounding an infant star that is saturated with water. In fact, the amount of water in this disk is enough to fill Earth’s oceans three times over.
Water has always been considered a crucial element in the formation and sustainability of life as we know it. This is the first time that astronomers have been able to map the distribution of water in a cool and stable protoplanetary disk, which is ideal for planet formation.
The team of researchers, led by Stefano Facchini from the University of Milan, used ALMA to zoom in on water vapor locked within the gas and dust of the protoplanetary disk surrounding the star HL Tauri. Located 450 light-years away from Earth in the constellation Taurus, HL Tauri is part of the Taurus Molecular cloud, one of the largest and closest star-forming regions to our planet.
ALMA’s sensitivity allowed astronomers to determine the distribution of water in different regions of the HL Tauri disk. They discovered that the most significant volume of water was found in a curved gap within the disk, which scientists have known about for some time. These ring-shaped grooves are believed to be formed as planets orbit young stars, gathering mass. Finding water within these grooves suggests that it is being accumulated by developing planets, potentially impacting their chemical compositions.
“This discovery reveals a substantial quantity of water vapor at various distances from the star, including a gap where a planet could potentially be forming,” said Facchini.
The significance of this discovery extends beyond our understanding of planet formation. It also showcases the remarkable capabilities of ALMA. Ground-based telescopes face challenges in distinguishing water at such vast distances due to the obscuring effects of vapor in Earth’s atmosphere. However, ALMA, located in the Atacama Desert region of Northern Chile at an elevation of 16,400 feet, operates in a dry atmosphere, minimizing the impact of water vapor on its observations.
“To date, ALMA is the only facility able to spatially resolve water in a cool planet-forming disk,” said Wouter Vlemmings, a professor at Chalmers University of Technology and a member of the research team.
This discovery opens up new possibilities for future research. ALMA is currently undergoing upgrades, and work is underway on the Extremely Large Telescope (ELT) in Chile. Both of these instruments could provide even greater detail and help astronomers gain a deeper understanding of the role water plays in planet formation.
“It is truly remarkable that we can not only detect but also capture detailed images and spatially resolve water vapor at a distance of 450 light-years from us,” said Leonardo Testi, an astronomer from the University of Bologna and a member of the research team.
The team’s findings were published in the journal Nature Astronomy, marking a significant milestone in our quest to unravel the mysteries of the universe and our place within it.