An American-led team of astrophysicists including Tel Aviv University Prof.
Tsevi Mazeh has discovered two new planets that revolve around a double sun,
each of which “chases” the other and reaches the same “starting point” every 7.5
Until now, only a handful of “exo-planets” in galaxies outside our
own solar system have been shown to go around a double sun; this is the first
double planet to do so.
The discovery was reported in the Wednesday issue
of the prestigious journal Science and announced in Beijing by
Prof. William Welsh, from the University of California, San Diego, at an
international astronomy conference.
The observation has been carried out
using only one instrument – a photometer that continually monitors the
brightness of over 145,000 main sequence stars in a fixed field of view. This
data is transmitted to Earth by Kepler, a space observatory (named in honor of
the 17thcentury German astronomer and mathematician Johannes Kepler), then
analyzed to detect periodic dimming caused by extrasolar planets that cross in
front of their host star.
Orginally due to end this year, the Kepler
mission launched in March 2009 by the US National Aeronautics and Space
Administration (NASA) to discover Earthlike planets orbiting other stars was
extended to 2016.
The mission – according to those involved – was
specifically designed to survey a portion of our region of the Milky Way galaxy
to discover dozens of Earth-size planets in or near the habitable zone and
determine how many of the billions of stars in our galaxy have such
One of the newly discovered planets could possibly sustain life,
the team said. The discovery proves that planetary systems that are like our
solar system could have been created around a double star.
explained that this discovery joins that of four previous ones – of Kepler 16,
34, 35 and 38. Thus there are now five double suns that have planets revolving
around them. But this is the first time that a system of two planets was found
to revolve around a double sun.
This is also important because most of
the stars (suns) in the universe “live as couples, like humans,” Mazeh
Kepler-47 is located 5,000 light-years away from us. One of the
planets circles their double suns every 49 days, while the second one does so in
The team is headed by Prof. Jerome Orosz of the
University of California, San Diego. The astrophysicists from the US and Israel
made the discovery by measuring the power of light from the double sun. This
power declines in a cyclical way, which testifies to the fact that planets
revolve around it, Mazeh said.
“Life” on a newly discovered planet would
be very interesting, even though it cannot actually be seen from here. During
some of the “sunsets,”one sun will start “twilight” and only later will the
second sun “set” and cause night, he said.
“Every new planet that is
discovered is a new world for us that helps us understand the process of
creation of the planet,” Mazeh concluded. “This is especially in surroundings so
different we are familiar with, in which in the center is only one sun. We can
discover new worlds, but only with advanced technology installed on [unmanned]
spacecraft that makes it possible to look deep into space.”