An international group of astronomers studying the “Space Hamburger” – an accretion disk surrounding a baby star – has detected copious complex organic molecules inside it. These molecules are an important component to forming life molecules and this research shows that they form at the very beginning of a star system.
The study, published in the Astrophysical Journal, focused on Herbig-Haro (HH) 212, a young protostellar system 1,300 light-years from Earth. The star itself is about 40,000 years old (younger than homo sapiens) which opens a unique window into a star's first moments.
Using the Atacama Large Millimeter/submillimeter Array (ALMA), the researchers identified formaldehyde, methanol, and even formamide, a prebiotic molecule that has been shown to create guanine when exposed to ultraviolet light at 130°C (266°F). Guanine is one of the components of DNA.
“It is so exciting to discover complex organic molecules on an accretion disk around a baby star,” lead author Chin-Fei Lee, from the Academia Sinica Institute of Astronomy and Astrophysics, said in a statement. “When such molecules were first found in the protoplanetary disk around a star in a later phase of star formation, we wondered if they could have formed earlier. Now, using ALMA’s unprecedented combination of spatial resolution and sensitivity, we not only detect them on a younger accretion disk but also determine their location."
"These molecules are the building blocks of life, and they are already there in the disk atmosphere around the baby star in the earliest phase of star formation,” he added.
HH 212 is about 20 percent the mass of the Sun and is releasing a powerful jet of material, which suggests that the star is accumulating material at a steady rate. The material comes from the disk, which extends for about 9 billion kilometers (5.6 billion miles). It has a thick dark feature in the middle, sandwiched between two shorter, brighter features – hence the "hamburger" nickname.
The disk is rich in simple elements and the intense UV radiation from the star is helping with the formation of the interesting chemistry that ALMA has detected.
“They [the complex organic molecules] are likely formed on icy grains in the disk and then released into the gas phase because of heating from stellar radiation or some other means, such as shocks,” added co-author Zhi-Yun Li of the University of Virginia.
Studying system like HH 212 will help us answer questions on how life molecules form and maybe even work out how life came to exist in the universe.