Have you ever imagined standing in your home’s terrace or on a street watching sky illuminated by two suns having different colors( orange and yellow) and sizes?
One sun rising from the east, while at the same time the other one setting off the west. How would the horizon look like?
Well, we cannot fully feel it’s essence unless we had been experiencing it.
Nasa’s kepler mission telescope which has to date researched on thousands of exo-planets(planets outside our solar system ) has just begin to discover circumbinary planets (ones revolving binary star systems).
kepler- 16 solar system , more than 200 light years away from Earth in our own Milky way galaxy, has two stars in the centre around which two recently discovered planets kepler 16-b and kepler 16-c orbit.
It takes around 225 days(same as Venus) for the planets to complete one revolution. One of the two suns planet exists in the habitable zone of the system.
Habitable zone is that area in which a planet orbiting it’s host star can have a possibility of possessing water and hence can support life.
But unlike our Earth, the two suns planet is cold(less than -75 degree Celsius), gaseous and thus unsustainable to live. Bad news!
Among the parent stars, one has about 69% of the mass of our sun, while the other one is only 20% and for that reason are less hot than our Sun.
an artists painting of two star system
Previously, there was a difference of opinion among the astronomers regarding the possibility of an orbiting planet around two stars, who themselves are in orbit about their center of mass.
Potential difficulties arise because the two suns planet has to move through two gravitation fields of different strengths, with net force changing all the time while the planet is on the move.
Many scientists believed, even if such a two suns planet formed there, it cannot have stable orbit and hence there is a possibility that either it is left free in the deep space moving away or it spirals and collide with one of the stars.
But this time there was a direct evidence of detecting circumbinary planet with the telescopic earth observatory.
The two suns planet while orbiting transited in front of the two suns and dimmed those suns’ light to 0.2% reaching the telescope.
Carefully measuring the dip in the stars’ brightness and weak gravitational field exertion by the kepler16-b and 16-c on their suns revealed that the masses of the two planets are approximated to be of Neptune and Saturn respectively.