Astronomers found information that could help them understand the formation of planets – the point where carbon monoxide freezes in the disk around a sun-like star.

Based on the calculation of the carbon monoxide (CO) “snowline” for the star TW Hydrae, the researchers found out that the gas solidifies up to the orbit of Neptune, where it could facilitate how the outer edges of the system form.

Principal investigator Chunhua Qi from the Harvard-Smithsonian Center for Astrophysics wrote in the report, "The carbon monoxide snow line is interesting, not only because carbon monoxide is abundant in the disks, but its snow line is the most accessible to direct observations due to its low freeze-out temperature — it's farther away from the star. It could mark the starting point where smaller icy bodies, like comets, and dwarf planets, like Pluto, would begin to form."

When a disk of dust and gas disintegrates due to gravity, stars are formed and the remaining particles orbit it in a disk of material.

Scientists claimed that planets eventually grow from huge clumps of dust and gas particles that passed through the disk. The process is assisted by frozen volatiles.

Qi also stated in an e-mail to that “The snow line provides more sticky solid grains, and enhances the planet formation efficiency and grain growth.”
However, identifying the location of these grains can be a challenge. Figuring the telltale signs of frozen compounds is complicated for scientist because of the products from volatiles outside the disk.

Since N2H+ is easily destroyed in the presence of CO gas, and is abundant where CO has frozen out, Qi and his team made use of a new technique for them to establish the region of the disk where CO freezes. Instead of carbon monoxide, they looked for the ion diazenylium (N2H+) around TW Hydrae, which lies 176 light-years from Earth with the use of the Atacama Large Millimeter Array (ALMA) in Chile.

“As long as the disk is gas-rich, so that there should be enough N2H+, we can use this ion to image the CO Snow line,” Qi said.

The report was published in the July 18 issue of Science.

Let us be hopeful that this new method be useful in providing more insight into how objects are being formed outside the solar system.