Can a planet be as large as the star that it orbits?
Recent observations have discovered that nearby Van
Biesbroeck's star might have
just such a large planet. Although VB
10 lies only about 20 light
years away, it is a small red
dwarf star so dim, at 17th magnitude,
that a telescope is needed to see it.
was previously known for its rapid proper
motion across the sky -- it
moves so fast it could cross a full moon
in only about 1,000 years.
By noting a wiggle
in VB 10's sky trajectory, astronomers
were able to infer the existence
of a planet several times the mass of Jupiter.
Although the star VB 10 is perhaps 10 times more massive than the
discovered planet VB 10b,
the star is likely more highly compressed and so the two might be
closely matched in size.
Such a system is envisioned
above with an artist's
Since faint M-type
stars like VB 10 are so common, planetary
systems surrounding them,
including planets larger than their parent star, might be more common
than planetary systems like our own Solar