The observation of data from the Kepler space telescope is among the first detections of this effect in double-star systems, NASA Jet Propulsion Laboratory in Pasadena, Calif., reported Thursday.
The dead star is a white dwarf, the burned-out core of a star like the sun, and is locked into an orbital dance with a small "red dwarf" star.
While the white dwarf is the smaller of the pair, it is more massive that its partner, astronomers said.
"This white dwarf is about the size of Earth but has the mass of the sun," Phil Muirhead of the California Institute of Technology in Pasadena said. "It's so hefty that the red dwarf, though larger in physical size, is circling around the white dwarf."
When the red dwarf passes behind the white dwarf, the gravity of the much more massive white dwarf causes the red star's light to bend and brighten by minute but measurable amounts, scientists said.
"Only Kepler could detect this tiny, tiny effect," Doug Hudgins, Kepler program scientist at NASA Headquarters in Washington, said. "But with this detection, we are witnessing Einstein's theory of general relativity at play in a far-flung star system."
One of the predicted effects of Einstein's theory of general relativity is that gravity bends light, a phenomenon called gravitational lensing astronomers have used to gather evidence of dark matter and dark energy, two mysterious ingredients in the universe, and also to discover new, distant planets, JPL said.