New analyses of a cosmic disk, made of dust and gas orbiting a small star, have revealed a large amount of water vapor in a specific area where small planets may begin to form. Astronomers have mapped, for the "first time," the distribution of water in a "protoplanetary disk" around a star that may be hospitable to life. The star, known as HL Tauri, located just 450 light-years away from the solar system, could help determine the origin of water on planet Earth.
Astronomer Stefano Facchini from the University of Milan stated, "Our latest images reveal a significant amount of water vapor at great distances from the star, including a gap where a planet is likely forming at this time. I never imagined we could capture a picture of oceans of water vapor in the same region where a planet might be forming."
Stars are born in dense clouds of dust and gas, where a highly dense knot collapses under the influence of gravity, beginning to rotate and organizing the surrounding material into a disk that orbits the nascent central star. Once the star is formed, any material that has not been affected by gravity and pulled in by the star begins to clump together with its surroundings to form other materials in the planetary system: planets, moons, asteroids, and comets.
Observations from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal concentric gaps in the disk around HL Tauri. Astronomers believe these are caused by planet formation, filtering materials in the disk as they orbit the star. The research team took new observations of the star using ALMA, employing two different wavelength ranges to target water vapor. They found a substantial amount of water in the inner region of the disk, within 17 astronomical units of the star, where Earth-like planets are expected to form. This area contains about 3.7 times the amount of water present in all of Earth's oceans. The researchers detected water in a well-known and prominent gap in the disk, indicating a very good chance of water being incorporated into any planets that may form there.
