Astronomers have spotted a record-setting fifth planet orbiting the sunlike star 55 Cancri, 41 light-years away in the constellation Cancer. Researchers say the planet, a "mini-Saturn" of about 46 Earth masses, lies fourth out from the star in a large gap between the third and fifth planets, placing it squarely in the estimated habitable zone around the star where water might remain liquid, according to the group's report, accepted for publication in The Astrophysical Journal.
Although the planet's size implies that it is a ball of hydrogen and helium gas incapable of supporting pools of liquid water, the finding raises the possibility that additional, earthlike planets might be discovered around it.
"This discovery of the first ever quintuple planetary system has me jumping out of my socks," says group member and veteran planet hunter Geoffrey Marcy, an astronomer at the University of California at Berkeley. "We now know that our sun and its family of planets is not unusual."
One of the first stars discovered to harbor an extrasolar planet or exoplanet, the 55 Cancri system has come to resemble a jumbo version of our own solar system. Its five planets all seem to orbit along relatively circular paths, and the farthest planet out, a gaseous behemoth the size of four Jupiters, revolves at roughly the same distance that separates Jupiter from the sun.
Jan 17, 11:40am
