Until year 2011, the oldest world that we knew of was PSR B1620-26b – a distant world orbiting the pulsar, PSR B1620-26. A pulsar is actually a neutron star, an incredibly dense relic of a star’s core, just a few dozen kilometres across in size.
Nobody expected to find any planets around them but in the early 1990s several were found, their gravity causing slight delays in the regular tick-tock-tick-tock of a pulsar’s radio pulses.
PSR B1620-26b, which is also in the same system as a white dwarf, was one of these exoplanets.
However in early 2012, the title of the oldest exoplanet known was snatched by not one, but two alien worlds right on our star’s doorstep at a short distance of 375 light years away.
Uncovered with the help of radial velocity, the duo dubbed HIP 11952b and HIP 11952c are gas giants orbiting a Sun-like star, with the hefty HIP 11952b completing its tango around its star in nine and a half months while its lighter companion whips around in a short seven days.
At an ancient 12.8 billion years, these gas giants are believed to have formed at the dawn of the universe, less than a billion years after the Big Bang and at a time where our very own galaxy had not completely formed.
However, all good things come to an end and astronomers have hinted that it will be game over for these planetary veterans as their host star evolves into a red giant, engulfing the alien worlds that it has borne for so long.