They are looking into how elements are formed in interstellar clouds. In the early universe during the big bang, helium was produced. But there are three elements between helium and carbon that are not produced in the big bang and not produced in stars in appreciable amounts. Those elements are lithium, beryllium and boron. The likely source of these involves cosmic rays.
Cosmic rays are mainly protons that travel near the speed of light throughout the galaxy.
The cosmic rays collide with interstellar carbon, nitrogen and oxygen, breaking them down. When the speeding cosmic ray hits carbon, lithium is produced. Knauth said that they studied two stars in the same interstellar cloud for 50 to 60 hours. They used the star as a light source and monitored how much starlight was absorbed depending on what atoms were in the gas cloud. But we don't see that larger amount.