Astronomers detect first evidence of gas condensing to molecular solids in baby solar system

Baby star with jets of new material
Click for original image.

Using a combination of ground- and space-based telescopes, astronomers have detected the first evidence of the gas and dust surrounding a young star condensing to molecular solids, thus beginning the initial stages of planet formation.

This newborn planetary system is emerging around HOPS-315, a ‘proto’ or baby star that sits some 1300 light-years away from us and is an analogue of the nascent Sun. Around such baby stars, astronomers often see discs of gas and dust known as ‘protoplanetary discs’, which are the birthplaces of new planets. … Their results show that SiO [silicon monoxide] is present around the baby star in its gaseous state, as well as within these crystalline minerals, suggesting it is only just beginning to solidify. “This process has never been seen before in a protoplanetary disc — or anywhere outside our Solar System,” says co-author Edwin Bergin, a professor at the University of Michigan, USA.

…With these data, the team determined that the chemical signals were coming from a small region of the disc around the star equivalent to the orbit of the asteroid belt around the Sun.

The false-color picture to the right, cropped, reduced, and sharpened to post here, was taken by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile. It shows jets blowing out from the central baby star. Orange indicates carbon monoxide, while blue is the silicon monoxide. Initially the astronomers detected these molecules using spectroscopy from the Webb Space Telescope. This ALMA image was then used to identify where these molecules were located in the system.

Earth forming around sun-like star?

proto-planetary disk

Worlds without end: The ground-based telescope ALMA has imaged a proto-planetary disk around a sun-like star that suggests an exoEarth is forming there the same distance from the star as our Earth is from our Sun.

The star, TW Hydrae, is a popular target of study for astronomers because of its proximity to Earth (approximately 175 light-years away) and its status as a veritable newborn (about 10 million years old). It also has a face-on orientation as seen from Earth. This affords astronomers a rare, undistorted view of the complete disk. “Previous studies with optical and radio telescopes confirm that this star hosts a prominent disk with features that strongly suggest planets are beginning to coalesce,” said Sean Andrews with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author on a paper published today in Astrophysical Journal Letters. “The new ALMA images show the disk in unprecedented detail, revealing a series of concentric dusty bright rings and dark gaps, including intriguing features that suggest a planet with an Earth-like orbit is forming there.”

Other pronounced gap features are located 3 billion and 6 billion kilometers from the central star, similar to the distances from the Sun to Uranus and Pluto in our own Solar System.

The image above right is the inner section of that disk, showing the gap at one astronomical unit, or about 100 million miles from the star, the same as the distance of the Earth from the Sun. Essentially, this relatively close star system is providing us a perfect opportunity to study the formation of a solar system not unlike our own.