Astronomers have found a rocky planet orbiting a small star, which is located within sight of the Earth’s telescopes.
The planet rotates too closely around the parent star, a red dwarf known as Gliese 1132, to keep the water on its surface in liquid form. But astronomers suspect that this distant world has another feature that is characteristic of having life, namely the atmosphere.
"We have long imagined how a rocky planet orbiting another star, especially a small star, may be similar or different from the planets of the solar system," said astronomer Zakory Bertha Thompson of the Massachusetts Institute of Technology.
The conditions of observation are perfect. The planet, known as GJ 1132b, is slightly larger than Earth and rotates in an orbit that is perpendicular to the line of observation from the Earth.
But a distinctive feature of this discovery is that the planet is located only 39 light years from us, that is, three times closer than the previously discovered Earth-type exoplanet. GJ 1132b was discovered in May using eight telescopes located at the Cerro Tololo Inter-American Observatory in Chile.
When GJ 1132b passes in front of the parent star, telescopes are able to analyze the part of the light passing through the atmosphere of the planet. Thanks to this analysis, scientists are able to identify chemical “fingerprints” of atmospheric gases and conditions in the planet’s atmosphere.
GJ 1132b should be the starting point. Its parent star is five times less than Sun, so the planet blocks a high percentage of light during its transit than similar planets passing in front of stars like the Sun. GJ 1132b makes a full turn every 1, 6 days, presenting many viewing opportunities.
“Astronomers like to use the planet’s transit method, as this method allows fairly accurately measuring the mass of the planet and its radius, thereby providing basic information about the exoplanet,” wrote astronomer Drake Deming in Nature magazine this week.
Rotating at a distance of only 1, 4 million miles from the parent star, GJ 1132b, most likely, is tidal blocked (like the Moon to the Earth) and all the time facing one side of the star. “The atmosphere can redistribute heat,” Deming writes in Discovery News. "Thus, on this planet it is unlikely that any place capable of supporting life will be found."
"The planet is very, very hot, perhaps even hotter than Venus," said Bertha Thompson. "Any water would evaporate immediately. Water molecules would break up into oxygen and hydrogen, and hydrogen would fly off into open space."
"We expect to see there an atmosphere similar to the atmosphere of Venus with a large amount of carbon dioxide and nitrogen. Depending on the initial amount of water, maybe it can have an atmosphere with a high content of oxygen," she added.
However, scientists will not have to wait long. Scanning the atmosphere of exoplanets is one of the main goals for the future NASA space telescope named after James Webb.
Meanwhile, astronomers plan to use the existing Hubble Space Telescope to see if GJ 1132b has a sister planet.
A study published in the journal Nature this week.