(ORDO NEWS) — A star 1,300 light-years from Earth may have just revealed one of the solar system’s best-kept secrets.
Its name is V883 Orionis. This is a young star, surrounded by a huge disk of matter, day merge into orbiting planets.
It is in this disk that scientists have unequivocally found water vapor circulating along with all the other dust and gas that are destined to become part of an alien world.
This suggests that the water of the solar system, including now on Earth, was present in the gaseous cradle from which the Sun was born; that she was here, not only to the Earth, but to the Sun, and helped our planet to grow.
“Now we can trace the origin of water in our solar system to the formation of the Sun,” says astronomer John Tobin of the US National Radio Astronomy Observatory.
Water is quite common in the universe, although without it, the Earth would not be the same “pale blue dot”.
It curls around the surface of the planet, soaks the atmosphere in the form of steam, falls from the sky. It seems to us quite ordinary, but without it we could not live; almost all chemical processes of life require it.
It is also an important component in the formation of the planets.
Stars are born from clouds of dust and gas in space; the dense clump collapses under the force of gravity and, as it spins, begins to wind up more material from the surrounding cloud, which turns into a disk that feeds the young star.
After the star has finished growing, all the other features of the planetary system form from what is left of the disk.
The dust grains stick together electrostatically, forming larger and larger clumps until the object is massive enough to be picked up by gravity.
Water is believed to play an important role in this process; beyond the point at which water vapor freezes, called the snow line, it coats the dust particles with ice, giving them extra stickiness that helps the particles stick together in the very first stages of planetary growth.
From the isotopes of hydrogen, we can determine where and how water is formed. Normal hydrogen has no neutrons in the nucleus. Heavy hydrogen, also known as deuterium, has one neutron in its nucleus.
Water molecules containing heavy hydrogen are known as heavy water and are formed under conditions different from those in which ordinary water is formed.
Here on Earth, we can trace some water back to comets because water-to-heavy water isotope ratios are similar. This suggests that water can bind in comets and asteroids and be delivered to planetary bodies.
But how water got into comets has not yet been fully explained. Now, by studying V883 Orionis, Tobin and his team have filled that gap.
“We can think of the path of water through the universe as a path. We know what the endpoints look like, which represent water on planets and in comets, but we wanted to trace this trail back to the origin of water,” Tobin says.
“We used to be able to link the Earth to comets and protostars to the interstellar medium, but we couldn’t link protostars to comets.
V883 Ori changed that and proved that water molecules in this system and in our solar system have the same ratio of deuterium to hydrogen.”
The star is so young that it is still growing, surrounded by a huge disk.
By studying the light emitted by this disk, the researchers were able to identify the spectral signature of water vapor; moreover, they determined the ratio of hydrogen isotopes.
“The V883 Orionis is the missing link in this case,” says Tobin.
“The composition of the water in the disk is very similar to comets in our solar system, supporting the idea that water in planetary systems formed billions of years ago, before the Sun, in interstellar space, and was inherited by both comets and the Earth, with relatively little changes.”
What makes the V883 Orionis so special is that it’s going through a burst of accelerated growth, which means it’s temporarily hotter than normal.
Most of the water in the accretion disks around protostars is frozen and exists as vapor only near the star, where it is hard to see.
However, the burst of activity in V883 Orion has pushed its snowline to a point much farther from the star than usual; any water closer than this snow line is steam.
Steam is much easier to detect and analyze than ice, so the researchers were able to reliably measure and quantify the isotopic composition of water in Orion’s disk V883.
More than 1,200 times the volume of Earth’s oceans drifts as steam around V883 Orionis.
The findings show that all the water in a planetary system comes almost directly from the clouds from which its star was born.
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