Today on Scientific Blogging I saw the story of HIP 13044 b, a gas giant orbiting a star called (ready for this?) HIP 13044. Two things make this an especially interesting exoplanet. (By the way — the fact that a planet discovered outside our solar system needs a little bit extra these days to qualify as especially interesting? Very fucking cool.) First, it seems to have survived the red giant phase of its star. HIP 13044 is in the late stages of its stellar life. It expanded after exhausting its supply of hydrogen, and is now burning helium. When that runs out, the star will expand again, this time likely engulfing HIP 13044 b.
As if that was not cool enough, HIP 13044 is also a part of what is known as the Helmi stream, a thread of ancient stars wrapped around our Milky Way that were originally part of another, now defunct galaxy. There are several such streams, and many such stars, but HIP 13044 is the first confirmed to be hosting planets.
In other words, HIP 13044 b is proof of what astronomers have long assumed but, until now, never observed: that planets can form in galaxies other than our own. It seems more likely than ever that planets, which by human reckoning numbered in the single digits as recently as twenty years ago, are a common feature of our universe. HIP 13044 b is one of nearly 500 extrasolar planets discovered and cataloged since 1992. But it is the first extragalactic planet.