Although the planet is not habitable, detecting it is a historic step in the ongoing search for signs of life on other planets, NASA's Jet Propulsion Laboratory in Pasadena, Calif., said Tuesday.
Super Earths are more massive than Earth but lighter than gas giants like Neptune. In visible light, such planets are lost in the glare of their stars, but using infrared light the Spitzer telescope was able to detect the super Earth.
The planet, about twice as big and eight times as massive as Earth, orbits a bright star called 55 Cancri in a mere 18 hours.
Spitzer measurements of the infrared light coming from the planet reveal it is likely dark, and its sun-facing side is more than 3,140 degrees Fahrenheit, hot enough to melt metal.
At 41 light-years away, the 55 Cancri system of five planets is relatively close to Earth.
Of the planets in the star's system, the planet detected by the Spitzer telescope, 55 Cancri e, is closest to the star and tidally locked, so one side always faces the star, astronomers said.
"When we conceived of Spitzer more than 40 years ago, exoplanets hadn't even been discovered," said Michael Werner, JPL Spitzer project scientist said. "Because Spitzer was built very well, it's been able to adapt to this new field and make historic advances such as this."