Astronomers have discovered a new Venus-like rocky exoplanet 39 light years away, which may be cool enough to potentially host an atmosphere.
If it does, it is close enough that we could study that atmosphere in detail with the Hubble Space Telescope and future observatories like the Giant Magellan Telescope, researchers said. "Our ultimate goal is to find a twin Earth, but along the way we've found a twin Venus," said astronomer David Charbonneau of the Harvard-Smithsonian Center for Astrophysics (CfA) in US. "We suspect it will have a Venus-like atmosphere too, and if it does we can't wait to get a whiff," said Charbonneau.
"This planet is going to be a favourite target of astronomers for years to come," said lead author Zachory Berta-Thompson of the Massachusetts Institute of Technology (MIT). The planet, known as GJ 1132b, orbits a red dwarf star only one-fifth the size of our Sun. The star is also cooler and much fainter than the Sun, emitting just 1/200th as much light. GJ 1132b circles its star every 1.6 days at a distance of 1.4 million miles. As a result, GJ 1132b is baked to a temperature of about 232 degrees Celsius. Such temperatures would boil off any water the planet may have once held, but still allows for the presence of an atmosphere. It is also significantly cooler than any other exoplanet confirmed to be rocky, researchers said.
GJ 1132b was discovered by the MEarth-South array, which is dedicated to the hunt for terrestrial worlds orbiting red dwarf stars. After MEarth-South detected a transit in real time, additional observations were gathered by the array and the Magellan Clay telescope in Chile. The team also measured the host star's gravitational wobble using the HARPS spectrograph to determine the planet's mass. They found that GJ 1132b is 16 percent larger than Earth, with a diameter of about 14805 km. It has a mass 60 percent greater than Earth. The resulting density indicates that the planet has a rocky composition similar to Earth.
The planet also has an Earth-like force of gravity. A person standing on the surface of GJ 1132b would weigh only about 20 percent more than they do on Earth. Since the red dwarf star is small, the relative size of the planet to the star is larger than it would be for a Sun-like star. This, combined with the star's close distance, makes it easier to detect and study any planetary atmosphere, should one exist, researchers said.
