HD 81809B is a unusual star which consists high abundance of lithium, a very volatile element, and it is easily destroyed in stars.

This is the first binary system to be found with this chemical difference, which is very unusual. Binary systems are 'like siblings' in that they are born from the same molecular cloud, meaning they have the same chemical composition. As with siblings, some differences in element abundances can appear due to physical processes. However, these differences will be much smaller than those of HD 81809. One is that the stars are not 'real siblings' and were born from different molecular clouds containing different elements. The other explanation is that star HD 81809B suffered a more drastic event during its evolution, such as ingesting a planet, which could have changed its chemical composition.

How is this star devouring plants then? Moedas suggests it could be the result of gravitational interactions between the binary stars disrupting the orbit that led to their deaths. Of course, it's almost always gravitational pull.

We can only estimate the amount of planetary material required, which we find to be 75 times the mass of Earth. It is possible that the star ingested three planets, each 25 times more massive than Earth. The event happened a few million years ago, and there are physical processes in the star that will 'clean up' the evidence and try to make the star's chemical abundance similar to that before the event.

https://www.space.com/astronomy/stars/one-of-these-twin-stars-has-likely-been-snacking-on-exoplanets

#Lithium #PlanetEater #HD81809B #BinaryStars #BinarySystem #Exoplanets #Science #Space