Andromeda galaxy planetsEdit
A team of scientists has used gravitational microlensing to come up with a tentative detection of an extragalactic exoplanet in Andromeda, our nearest large galactic neighbour. The lensing pattern fits a star with a smaller companion weighing just 6 or 7 times the mass of Jupiter. This suspected planet is the first announced in the Andromeda Galaxy.
HIP 13044 is a star around 2000 light years away from Earth, but it is within the Milky Way galaxy which was found to have an exoplanet. However, this star is part of the Helmi stream of stars, a leftover remnant of a small galaxy that collided with and was absorbed by the Milky Way over 6 billion years ago, which means that the star is over 6 billion years old. So, although the star and its planet are now part of the Milky Way, they originally formed in another galaxy which either orbited the Milky Way or had a close pass to it. Thus, the planet HIP 13044 b, orbiting around the star HIP 13044, was once an extragalactic planet.