The planet circles too close to its parent star, a red dwarf known as Gliese 1132, for any water to remain liquid, a condition believed to be necessary for life. But astronomers suspect it has other attributes that are directly related to the search for life beyond Earth, namely an atmosphere.
“We have long imagined how rocky planets around other stars -- particularly small stars -- maybe be similar or distinct from the planets in the solar system,” Massachusetts Institute of Technology astronomer Zachory Berta-Thompson wrote in an email to Discovery News. “With this planet, we will finally be able to observe one! "
Viewing conditions should be ideal. The planet, known as GJ 1132b, is slightly bigger than Earth and is in an orbit that is nearly edge-on to an Earth-based observer’s line of sight.
The trump card is that the system is only 39 light-years away, a stone’s throw by cosmic yardsticks and three times closer than any previously discovered Earth-sized planet.
It was discovered in May with an eight-telescope array located at the Cerro Tololo Inter-American Observatory in Chile.
As GJ 1132b passes in front of its star, telescopes will be able to measure the small fraction of starlight that passes through the planet’s atmosphere. Scientists can then analyze the light for telltale chemical fingerprints of atmospheric gases and conditions. Ultimately, scientists want to be able to scan distant planets’ atmospheres for chemical signatures of life.
GJ 1132b should prove an excellent starting point. Its parent star is about one-fifth the size of the sun, so the planet blocks a higher percentage of starlight during transits than similarly sized planets orbiting sun-like stars. GJ 1132b also transits every 1.6 days, presenting lots of viewing opportunities.
“Astronomers love transiting planets because the transit geometry allows them to unambiguously measure a planet’s mass and radius (and thus to determine its bulk density), thereby providing basic information about its chemistry,” University of Maryland astronomer Drake Deming wrote in a commentary in this week’s Nature.
Orbiting just 1.4 million miles from its parent star, GJ 1132b is likely tidally locked (like the moon is to Earth) with a hot side of the planet facing the star, and a cool one facing away.
“An atmosphere could redistribute the heat,” Deming wrote in an email to Discovery News. “The equilibrium temperature we calculate for this planet is above the habitable range, but with tidal locking and modest heat redistribution there could be habitable regions on the planet.”
Read more at Discovery News
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