A team of Japanese astronomers came up with a new technique for weighing a protoplanetary disk without visiting it first.
Not only that. This technique is the best method of measurement without first assuming the relative amounts of the various gases in the disk.
When young stars form, there is usually a ring or disk of gas and dust orbiting around them. We know it as a protoplanetary disk. Planets like those in the Solar system, formed within the area of the protoplanetary disk.
To study the protoplanetary disk, radio waves are the main trace. From the protoplanetary disk astronomers can understand the composition of the constituent material as well as the process of planet formation.
One of the main ingredients in the protoplanetary disk is hydrogen gas (H2). However, H gas2 it does not emit strong radio waves so it is not easy to directly measure the amount of hydrogen in the disk. Because of this, astronomers turned to carbon monoxide (CO), the second most abundant gas on the disk. This gas is used as a substitute or proxy for hydrogen. However, recent studies have shown that this method is not as precise as the researchers hoped. So, the ratio of hydrogen to carbon monoxide can be different depending on the environment. Consequently there is great uncertainty in the estimation of the total mass.
Because of this, a team of Japanese astronomers came up with a different idea. Together with his colleague, Tomohiro Yoshida from University for Advanced Studies in Japan, began studying the closest protoplanetary disk known to us.
It studied TW Hya, the protoplanetary disk around TW Hydrae, a star 196 light years from Earth (nearly 50 times farther from Alpha Centauri) in the constellation Hydra.
Yoshida and his team use data Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to obtain more detailed images of TW Hya dishes at radio wavelengths. As a result, they obtained images 15 times better than previous studies. With these results, the team of astronomers analyzed not only the wavelengths of various materials in the disk, such as CO, but also their shape.
From the shape of the CO spectral lines, Yoshida and the team can measure in more detail the pressure and the total mass of the gas without the need to make initial assumptions about the ratio of hydrogen to carbon monoxide. With the new technique, Yoshida and his team began investigating different types of protoplanetary disks to better understand the process.
Cool Facts
While studying the TW Hydrae system, astronomers discovered that this system is in the final stages of planet formation. Despite this, enough gas remained in the inner regions to form a Jupiter-sized planet!
Source: This article is a republished version developed from Indonesian edition of Space Scoop Universe Awareness. The Indonesian edition of Space Scoop is translated by Langitselatan.
