Astronomers watch a star eat its own planet

An international team of astronomers has found evidence of a planet being eaten by its star, a fate which is presumed to be common for inner planets as their suns age and expand. Ha ha, sucks for that planet! Hey, wait a second, was that inner planets? That's us! We're an inner planet. Uh oh.

Yes, as horrible as it may seem, our sun is eventually going to kill and eat all of us as it changes from a yellow dwarf into a red giant, a typical transformation for aging stars that lie on the beach without sunblock and that have stopped exercising. Not too long from now, the sun is going to run out of hydrogen in its core, at which point it'll begin to fuse helium instead. The core will contract and heat up, the sun will eventually expand to double its current size while increasing in temperature, and tidal interactions will probably cause Earth to be nommed up.

Once a star has decided that yes, a planet is just what it's craving right now, the process of consuming said planet doesn't take very long, which is why it's so remarkable that astronomers have caught a star with the fridge door open and planet crumbs around its mouth, as it were. BD+48 740, a red giant, has been observed to contain a high amount of lithium, which isn't ordinarily present in older stars. Really the only way BD+48 740 could have got all of this lithium if it was produced as it digested a planet-sized mass. Also, BD+48 740 has a second planet orbiting it, a gas giant about 1.6 times the size of Jupiter. This gas giant has a wonky elliptical orbit, which was likely caused by the final death dive of the first planet as it was swallowed up by the star.

So, how long to we have until our sun gets violently peckish? Earth will likely only last another five billionish years, which means that yes, now is absolutely the time to panic and buy that bomb shelter you've been saving up for, because the sun is really just the largest thermonuclear weapon this solar system has ever seen.

Penn State, via Universe Today

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