The Sun’s ‘Star DNA’ Could Help Find Its Closest Relatives

Our solar system is like a small family living in a condo when compared to the rest of the universe. But really how much do we know about our solar system? As it turns out, a lot; thanks to our brilliant scientists who have been studying it for centuries. For the past five years, scientists have been working on finding our Sun’s lost family by examining its ‘DNA’.

The ‘DNA’ of the Sun refers to the number and amount of specific chemical elements it is made up of. Stars usually contain elements such as aluminum, iron and oxygen. Astronomers first collected the data from our Sun regarding the elements it has and then compared it with other stars nearby and look for any similarities. They were looking for the stars that were born with Sun in the same stellar nursery.

After the Big Bang event, when the universe was formed, it only had two elements which were hydrogen and helium. The rest of the periodic table came into being later on as stars fused hydrogen and helium into more massive elements. These heavier elements then helped shape stars and planets to form a perfect system.

The Anglo-Australian telescope in New South Wales, Australia.

A huge project was launched in 2013 known as GALactic Archeology with HERMES (GALAH). This project brought together scientists from Australia and Europe with the goal of observing more than 1 million stars to determine their constituting elements. The instrument used in this project was HERMES which stands for High Efficiency and Resolution Multi-Element Spectrograph. The HERMES instrument was installed in the Anglo-Australian Telescope (AAT) in New South Wales, Australia. HERMES is used to photograph the light from the stars in four different optical bands which are red, green, blue and infrared, as confirmed by the Australian Astronomical Observatory (AAO).

On April 18th of this year, the first data from this enormous project was finally released to the public. In the release of the data, scientists revealed that they successfully examined 340,000 stars in the Milky Way.

HERMES played a huge role in helping scientists achieve such a remarkable feat in only a few years time. During the GALAH project, the AAT would gather light from 360 stars simultaneously. HERMES would then split the light into the four optical bands for the scientists to have a closer look. The Spectra revealed the different amount of elements present in the stars through the dark bands where the light was blocked.  Each element has a distinguishable wavelength that can be clearly seen on the spectral lines revealed by HERMES. The combined spectral lines of all the elements combine to form the ‘DNA’ signature of a star.

Spectral lines like this are recorded from the light we observe from stars. Each row represents a different element; from top to bottom: Hydrogen, Helium, Carbon, and Aluminum.

The data was then analyzed by software named “the Canon” (named after Annie Jump Canon, a pioneering U.S astronomer). Canon would use the data to find matches between the stars to find the ones that were born in the same nursery. But since the cluster of the Milky Way has been scattered randomly, scientists have found it difficult so far to find any solar sibling of our Sun. But the astronomers working on GALAH are still focused and determined to finally locate the stars that came into existence with our Sun.