This mass transfer between the stars will also cause their mutual orbit to shrink.

This can cause changes in the rotation periods for both bodies as well as modification of their mutual orbit.

Gravity had drawn them into mutual orbits, their own growing mass finally cooking off the fusion of hydrogen deep within the stellar envelopes.

Most stars in the sky are not solitary suns like our own, but double or multiple systems in which the stars are in mutual orbit.

The two stars now share a common envelope, causing their mutual orbit to shrink.

The Kepler team identified 750 eclipsing binary systems in which the stars are in close mutual orbit, and examined the data for smaller, secondary eclipses.

Stockton argues that we are here seeing a pair of galaxies in mutual orbit.

Those two probably condensed out of the Rosette, and all three attracted each other and went into a mutual orbit.

It shares a tight mutual orbit and an atmosphere with the Planet Water, which is the afterlife for all good souls in the Lexx universe.

However, their eccentric mutual orbit causes their distance to vary between 5.5 AUs at periastron, to 13.5 at apastron.