Snow falling around infant solar system

Cosmic frost! Astronomers have discovered a snowy region in a far-off baby solar system, 175 light years away from the Earth.
The snow line, located in the disc around the Sun-like star TW Hydrae, has been imaged in a far-off infant solar system for the very first time.
The discovery promises to bring out more about the formation of planets and comets, the factors that decide their composition, and the history of the Solar System.
Astronomers using the Atacama Large
Millimetre/submillimeter Array imaged the snow line in an infant solar system.
On Earth, snow lines form at high altitudes where falling temperatures turn the moisture in the air into snow. This line is clearly visible on a mountain, where the snow-capped summit ends and the rocky face begins.

The snow lines around young stars form in a similar way, in the distant, colder reaches of the dusty discs from which solar systems form. Starting from the star and moving outwards, water (H2O) is the first to freeze, forming the first snow line.

Further out from the star, as temperatures drop, more exotic molecules can freeze and turn to snow, such as carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO).
These different snows give the dust grains a sticky outer coating and play an essential role in helping the grains to overcome their usual tendency to break up in collisions, allowing them to become the crucial building blocks of planets and comets.

The snow also increases how much solid matter is available and may dramatically speed up the planetary formation process.
Each of these different snow lines may be linked to the formation of particular kinds of planets.
The snow line spotted by ALMA is the first glimpse of the carbon monoxide snow line, around TW Hydrae, a young star 175 light-years away from Earth. Astronomers believe this budding solar system shares many of the same characteristics of the Solar System when it was just a few million years old.
"We can now see previously hidden details about the frozen outer reaches of another solar system similar to our own," said Chunhua Qi from the Harvard-Smithsonian Center, Cambridge, one of the two lead authors of the paper.

But the presence of a carbon monoxide snow line could have greater consequences than just the formation of planets.
Carbon monoxide ice is needed to form methanol, which is a building block of the more complex organic molecules that are essential for life.
The study was published in Science Express.