(ORDO NEWS) — In recent years, astronomers have discovered a large number of exoplanets orbiting single “normal” stars. A new study shows that there may be a significant number of exceptions to this trend.
The authors, led by Carlos E Chavez of the Autonomous University of Nuevo Leon, Mexico, propose a new method for detecting dim bodies, including planets, orbiting exotic binary stars known as cataclysmic variables.
Cataclysmic variables are binary star systems in which two stars are in close contact, such that the less massive component transfers mass to the more massive companion.
Typically, cataclysmic variables consist of a small, cool star known as a red dwarf and a hotter, denser star known as a white dwarf.
A red dwarf has a mass of 0.07 to 0.30 solar masses and a radius of about 20 percent of the radius of our star, while white dwarf stars usually have a mass of about 0.75 solar masses with a very small radius close to the radius of planet Earth.
In the cataclysmic variable system, as a result of mass transfer from a smaller star to a more massive star, a bright accretion disk appears, the luminosity of which exceeds the luminosity of the two stars in the system.
The third body of the system affects the flow of matter from a smaller star to a more massive luminary and thus changes the observed brightness of the accretion disk.
Analyzing these changes in the observed brightness of the cataclysmic variable, it is possible to establish the nature and fundamental parameters of the third component of the system, the authors show.
By applying their method to four known cataclysmic variable stars, Dr. Chavez and his team were able to find that the changes in system brightness associated with the third body occur on large time scales compared to the orbital periods of the triple system.
Two of the four studied systems of cataclysmic variables presumably contained a third body of planetary type.
Chavez and his team believe that their proposed method will allow the discovery of a large number of new exoplanets in binary star systems, in addition to the thousands of such planets already discovered in the past three decades.
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