COPENHAGEN, Denmark — That famous “Star Wars” scene of Luke Skywalker gazing out at two suns in a galaxy far, far away may be more accurate than many people think! Aliens could be springing to life and soaking up the sun in planetary systems with two stars, according to new research.
Researchers from the University of Copenhagen say nearly half of the stars which are the same size as our home sun come in pairs — called binary systems. In these solar systems, the pair of stars are gravitationally bound together and orbit each other.
Their combined energy extends the habitable region further out into space, increasing the odds there could be habitable planets nearby. The stars heat each other’s worlds, also meaning they have a greater chance of sustaining planets with liquid water — a key component for life as we know it.
“The result is exciting since the search for extraterrestrial life will be equipped with several new, extremely powerful instruments within the coming years. This enhances the significance of understanding how planets are formed around different types of stars. Such results may pinpoint places which would be especially interesting to probe for the existence of life,” says project leader Professor Jes Kristian Jørgensen from Copenhagen’s Niels Bohr Institute in a university release.
Binary systems may have enough heat to make life
The discovery is based on observations made by the ALMA telescopes in Chile, which examined a young binary star system about 1,000 light years from Earth. Named NGC 1333-IRAS2A, it’s surrounded by a disc of gas and dust. The international team created computer simulations going backwards and forwards in time.
“The observations allow us to zoom in on the stars and study how dust and gas move towards the disc. The simulations will tell us which physics are at play, and how the stars have evolved up till the snapshot we observe, and their future evolution,” explains Postdoc and study second author Rajika L. Kuruwita.
Notably, the movement of gas and dust does not follow a continuous pattern. For “relatively” short spells over thousands of years, it becomes very strong. The binary star becomes up to one hundred times brighter, before returning to its regular state. Presumably, the cyclic pattern can be explained by duality. The two stars encircle each other.
At given intervals, their joint gravity will affect the surrounding disc in a way which causes huge amounts of material to fall towards the star.
“The falling material will trigger a significant heating. The heat will make the star much brighter than usual,” adds Kuruwita. “These bursts will tear the gas and dust disc apart. While the disc will build up again, the bursts may still influence the structure of the later planetary system.”
Too early for life to emerge?
The stellar system described in the journal Nature is still too young for planets to have formed.
“Comets are likely to play a key role in creating possibilities for life to evolve. Comets often have a high content of ice with presence of organic molecules. It can well be imagined that the organic molecules are preserved in comets during epochs where a planet is barren, and that later comet impacts will introduce the molecules to the planet’s surface,” Prof. Jørgensen explains.
“The heating caused by the bursts will trigger evaporation of dust grains and the ice surrounding them. This may alter the chemical composition of the material from which planets are formed,” Jørgensen continues.
“The wavelengths covered by ALMA allow us to see quite complex organic molecules, so molecules with 9-12 atoms and containing carbon. Such molecules can be building blocks for more complex molecules which are key to life as we know it. For example, amino acids which have been fund in comets.”
Help is on the way in the search for alien life
ALMA (Atacama Large Millimeter/submillimeter Array) has 66 telescopes operating in coordination. This allows for a much better resolution than a single telescope can obtain. The new James Webb Space Telescope (JWST) launched last Christmas will soon join the search for extraterrestrial life.
By the end of the decade, the ELT (European Large Telescope) and the extremely powerful SKA (Square Kilometer Array) will complement ALMA and James Webb. The ELT — with its 39-meter mirror — will be the biggest optical telescope in the world and will observe the atmospheric conditions of exoplanets outside the solar system.
SKA will consist of thousands of telescopes in South Africa and in Australia working in coordination and will have longer wavelengths than ALMA.
“The SKA will allow for observing large organic molecules directly. The James Webb Space Telescope operates in the infrared which is especially well suited for observing molecules in ice. Finally, we continue to have ALMA which is especially well suited for observing molecules in gas form. Combining the different sources will provide a wealth of exciting results,” Jørgensen concludes.
South West News Service writer Mark Waghorn contributed to this report.