Astronomers working with the United Kingdom Infrared Telescope
on Hawaii have discovered four pairs of stars that orbit each
other in less than 4 hours. © J. Pinfield / RoPACS network This
artist's impression shows the tightest of the new record
breaking binary systems. Until now it was thought that such
close-in binary stars could not exist. About half of the stars
in our Milky Way galaxy are, unlike our Sun, part of a binary
system in which two stars orbit each other. Most likely, the
stars in these systems were formed close together and have been
in orbit around each other from birth onwards. It was always
thought that if binary stars form too close to each other, they
would quickly merge into one single, bigger star. This was in
line with many observations taken over the last three decades
showing the abundant population of stellar binaries, but none
with orbital periods shorter than 5 hours. For the first time,
the team has investigated binaries of red dwarfs, stars up to
ten times smaller and a thousand