The James Webb Space Telescope’s Mid-InfraRed Instrument (MIRI) is making groundbreaking discoveries in the outer reaches of universe. Recently, it has detected water vapour in the inner disc of the system PDS 70, located 370 light-years away. This is the first detection of water in the terrestrial region of a disc already known to host two or more protoplanets, a milestone achievement for space exploration.
Water is a vital component of life as we know it, and scientists have long debated the origins of this precious resource and whether similar processes are occurring in other star systems.The system PDS 70, located roughly 370 light-years away, hosts an inner disc and an outer disc separated by a gap of 8 billion km. Within this gap are two gas-giant planets. The new data collected from the system using the powerful Mid-InfraRed Instrument (MIRI) aboard the James Webb Space Telescope revealed water vapour present in the inner disc at distances of less than 160 million km from the star. This is an exciting find, as it probes the region where rocky planets like Earth typically form and could provide valuable insights into how water arrived on our planet and if similar processes could bring water to other rocky exoplanets orbiting distant stars.
“We’ve seen water in other discs, but not so close in and in a system where planets are currently assembling,” said lead author Giulia Perotti of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. Thomas Henning, principle investigator of MIRI and co-principal investigator of the MINDS (MIRI Mid-Infrared Disk Survey) programme that took the data, added that this discovery is “extremely exciting” as it “probes the region where rocky planets similar to Earth typically form”.
It is believed that water first arrived on Earth via icy comet or asteroid impacts, however it is still unclear if this was a one-off occurrence or if similar impacts intermittently delivered water over millions of years. By examining the composition of other planetary systems, particularly those with gas-giant planets in similar orbits to our own solar system, we may gain further insight into Earth’s water origins and other potential sources.The findings from PDS 70 are just the latest step forward in our understanding of water’s role in our universe. By continuing to explore our own systems and those beyond our solar system, we hope to gain more knowledge about how water arrived on Earth and whether different processes could bring similar resources to other rocky exoplanets across our galaxy.
Are moist environments necessary for the formation of planets?
Astronomers have made a surprising discovery about the star PDS 70—an estimated 5.4 million-year-old K-type star cooler than the Sun. A team of researchers led by the Max Planck Institute for Astronomy in Germany found evidence of water vapour in the central regions of the star’s planet-forming disc, which is much older than previously thought possible. This finding could have significant implications for understanding the potential formation of rocky planets in this system.The discovery of water vapour in a disc around a star as old as PDS 70 is contrary to what was previously known about these systems. It was believed that the central stars’ radiation and wind forces would remove gas and dust from the discs, or that dust grains would grow into larger objects that would eventually form planets. As a result, astronomers expected the inner regions of such discs to be dry and devoid of any materials needed to form rocky worlds.
However, that’s not what was found when studying PDS 70. In addition to the presence of water vapour, astronomers observed a relatively large amount of small dust grains. This combination could be an exciting development for understanding the potential formation of planets within this system. As Rens Waters, one of the co-authors from Radboud University in the Netherlands, noted, “The inner disc is a very exciting place.”That’s because if rocky planets are indeed forming within this system, they would be able to access water from the beginning stages of their formation. This is great news for researchers working to understand planetary habitability in other star systems, as water is often considered an essential element for life to exist. Despite this intriguing discovery, astronomers have yet to detect any planets forming within the inner disc of PDS 70. That means more research will be needed to determine whether there are any planets with the potential for hosting life within this system.
What is the reason for the origin of water?
The NASA James Webb Space Telescope has revealed the presence of water vapor in the inner regions of the protoplanetary disks of two young stars. This is the first time water vapor has been detected in such close proximity to a star, and it raises exciting questions about the origin and fate of water in these disks.The two stars, PDS 70 and Elias 2-27, are part of a class of young stars known as protoplanetary disks. As their name implies, protoplanetary disks are discs of material which orbit around a star and contain much of the material from which planets form. Scientists believe that the presence of water vapor so close to these stars could be a sign that planets are beginning to form near them.
The discovery raises the question of where the water came from.The team behind the discovery considered two different scenarios to explain their finding: either water molecules are forming in place, or ice-coated dust particles are being transported from the cool outer disc to the hot inner disc, where they sublimate into vapour. Though both scenarios are possible, scientists would be surprised if dust particles were able to cross the large gap carved out by two giant planets. Another question raised by the discovery is how water could survive so close to the star, where ultraviolet light should break apart any water molecules. It is believed that surrounding material, such as dust and other water molecules, acts as a protective shield which helps the water molecules survive destruction.
Using instruments aboard Webb, such as the Near-InfraRed Camera (NIRCam) and Near-InfraRed Spectrograph (NIRSpec), scientists will continue to study the PDS 70 system in an effort to gain an even better understanding of how water forms and survives in protoplanetary disks. In addition to providing valuable insight into how planets form, this discovery could also help scientists gain a better understanding of water on Earth. The presence of large amounts of water vapor in protoplanetary disks could mean that Earth’s oceans were created from material that originated in these discs around young stars. This exciting new discovery has been published in the journal Nature and more research will continue to be done in order to further explore this phenomenon. As more is understood about how water behaves in these discs, scientists will be able to better understand our own planet’s origins and answer questions about how our oceans were formed.
