our strange stellar neighbors…
Is VB 10 a planet-sized star, or is VB 10a a star-sized planet? One of our closest stellar neighbors poses a small but interesting challenge to cosmic taxonomy.
You would think that a star that’s barely big enough to be one, shouldn’t have a planet orbiting around it. When our Sun coalesced, it’s thought that our entire solar system formed from a small percentage of the dust cloud that served as the star’s fuel. So for a tiny red dwarf which barely burns hydrogen there probably wouldn’t be a whole lot of material for planetary formation left after its birth. And yet, just 20 light years away, such a tiny red dwarf known as VB 10, is home to a planet six times the mass of Jupiter, orbiting only 50 million miles out.
As the gas giant around VB 10 travels around its star, it tugs the red dwarf with enough force to make the star itself spin in a little circle around a common center of gravity. And interestingly enough, the planet and the star are probably the same size. When a planet gets as big as Jupiter, its size doesn’t increase with more mass. Instead, it just gets denser. The star is also limited in its size since it needs to be small and dense enough to sustain fusion. This means we’re probably looking at two Jupiter sized objects spinning around each other as one blasts the other with intense flares every now and then. VB 10 is a red dwarf and when its magnetic fields go wild, it belches out a massive dose of X-rays.
Now, where else are you going to find something like that but in nature? What science fiction tale set in deep space ever predicted such a system? Until we started detecting extrasolar worlds, the media was picturing solar systems much like our own. Several rocky worlds close to a star, gas giants farther out and a couple of frozen ice balls on the fringes, surrounded by leftover materials form planetary formation. The reality turns out to be very different and it may very well be that systems like ours are the oddballs in this chaotic universe.