Planets around binary stars as targets in the search for alien life
Nearly half of Sun-size stars are binary. According to a new study by a group of international researchers, planets around binary stars may be very different from those around the Sun.
The results from the project are published in the distinguished journal Nature on May 23, 2022. A group from Denmark, USA, and Taiwan’s NTHU used ALMA (Atacama Large Millimeter/submillimeter Array) telescope in Chile to observe an object 1000 light-years away. A snap shot of the young binary star system NGC 1333-IRAS2A that formed some 10,000 years ago was taken. The study is combined with a magneto-hydrodynamic simulation that can look at the system backward and forward in time.
The flow of the gas surrounding the young binary is rather chaotic. The chaotic movement can trigger an outburst where a stream of material falls toward the star. The young star becomes ten to one hundred times brighter, and then returns to its normal state. During the outburst, the gas and dust in the planet-forming disc were torn apart. During the build-up of the disc, the outburst affects the structure of future planetary systems.
Daniel Harsono, a co-author from National Tsing-Hua University, was heavily involved in the analysis of the gas in the disc that includes water, methanol, and other complex organics, molecules with 9–12 atoms that contain carbon. Planets are formed out of small rocky bodies like the comets in the Solar System. Some of the organic molecules are preserved in comets during epochs when a planet is barren and the molecules will be introduced to the planets when comet impacts the young planet. The heating from the outbursts triggers the destruction of gas and dust that may change the material from which planets are formed.
Very soon the new James Webb Space Telescope will join the search for complex organic molecules in ice. Daniel Harsono is a principal investigator of one of the projects that will study the gas and dust around young stars. The grand question is whether planetary systems around multiple star systems are very different from those around single stars. This is yet unknown, but the recent results elucidate the problem for the coming years.
URL:https://www.nature.com/articles/s41586-022-04659-4
Some of the press releases:
https://news.umich.edu/planets
https://news.ku.dk/all_news/20
https://nature.altmetric.com/d