A team of astronomers has discovered a new rocky, Earth-sized exoplanet orbiting a star approximately 39 light-years away.
The newfound world, named GJ 1132b, orbits a red dwarf star known as GJ 1132 (Gliese 1132), which is only 1/5 the size of the Sun.
The star is also cooler and much fainter than our Sun, emitting just 1/200th as much light.
GJ 1132b, also known as Gliese 1132b, circles its host star every 1.6 days at a distance of 1.4 million miles. As a result, the exoplanet is baked to a temperature of about 450 degrees Fahrenheit (232 degrees Celsius).
“The temperature of the planet is about as hot as your oven will go, so it’s like burnt-cookie hot. It’s too hot to be habitable – there’s no way there’s liquid water on the surface. But it is a lot cooler than the other rocky planets that we know of,” said Dr Zachory Berta-Thompson of the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research.
In comparison, well-known hot exoplanets like CoRoT-7b and Kepler-10b possess scorching temperatures of 2,000 degrees Fahrenheit (1,090 degrees Celsius) or more.
According to Dr Berta-Thompson and co-authors, GJ 1132b is likely tidally locked, meaning that it has a permanent day and night side, presenting the same face to its star, much like the Moon is locked to the Earth.
The astronomers calculated that the exoplanet is about 1.2 times the size of Earth, with a diameter of about 9,200 miles (14,800 km), and its mass is 1.6 times the mass of the Earth.
Given its size and mass, the scientists could determine its density – and they believe it to be rocky, like our home planet.
GJ 1132b also has an Earth-like force of gravity. A person standing on the surface of the exoplanet would weigh only about 20% more than they do on Earth.
The exoplanet was discovered by the MEarth-South Observatory, an array of eight 40-cm robotic telescopes located at the Cerro-Tololo Inter-American Observatory in Chile, which is dedicated to the hunt for rocky exoplanets orbiting red dwarfs.
After MEarth-South Observatory detected a transit of GJ 1132b across the surface of its parent star in real time, additional observations were gathered by the array and the Magellan Clay telescope in Chile.
Dr Berta-Thompson and his colleagues also measured the parent star’s gravitational wobble using the HARPS spectrograph to determine the mass of GJ 1132b.
The newfound exoplanet, according to the team, is cool enough to potentially host an atmosphere.
“The new planet is a good deal cooler than other nearby rocky planets that have been discovered so far. This means that GJ 1132b likely has a substantial atmosphere,” said Prof. Jonathan Fortney of the University of California at Santa Cruz.
“What is tremendously exciting to me is that this planet could be a real cousin of Venus and Earth.”
“We finally have a target to point our telescopes at, and can dig much deeper into the workings of a rocky exoplanet,” Dr Berta-Thompson concluded.
The discovery is reported November 12 in the journal Nature.
The newfound world, named GJ 1132b, orbits a red dwarf star known as GJ 1132 (Gliese 1132), which is only 1/5 the size of the Sun.
The star is also cooler and much fainter than our Sun, emitting just 1/200th as much light.
GJ 1132b, also known as Gliese 1132b, circles its host star every 1.6 days at a distance of 1.4 million miles. As a result, the exoplanet is baked to a temperature of about 450 degrees Fahrenheit (232 degrees Celsius).
“The temperature of the planet is about as hot as your oven will go, so it’s like burnt-cookie hot. It’s too hot to be habitable – there’s no way there’s liquid water on the surface. But it is a lot cooler than the other rocky planets that we know of,” said Dr Zachory Berta-Thompson of the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research.
In comparison, well-known hot exoplanets like CoRoT-7b and Kepler-10b possess scorching temperatures of 2,000 degrees Fahrenheit (1,090 degrees Celsius) or more.
According to Dr Berta-Thompson and co-authors, GJ 1132b is likely tidally locked, meaning that it has a permanent day and night side, presenting the same face to its star, much like the Moon is locked to the Earth.
The astronomers calculated that the exoplanet is about 1.2 times the size of Earth, with a diameter of about 9,200 miles (14,800 km), and its mass is 1.6 times the mass of the Earth.
Given its size and mass, the scientists could determine its density – and they believe it to be rocky, like our home planet.
GJ 1132b also has an Earth-like force of gravity. A person standing on the surface of the exoplanet would weigh only about 20% more than they do on Earth.
The exoplanet was discovered by the MEarth-South Observatory, an array of eight 40-cm robotic telescopes located at the Cerro-Tololo Inter-American Observatory in Chile, which is dedicated to the hunt for rocky exoplanets orbiting red dwarfs.
After MEarth-South Observatory detected a transit of GJ 1132b across the surface of its parent star in real time, additional observations were gathered by the array and the Magellan Clay telescope in Chile.
Dr Berta-Thompson and his colleagues also measured the parent star’s gravitational wobble using the HARPS spectrograph to determine the mass of GJ 1132b.
The newfound exoplanet, according to the team, is cool enough to potentially host an atmosphere.
“The new planet is a good deal cooler than other nearby rocky planets that have been discovered so far. This means that GJ 1132b likely has a substantial atmosphere,” said Prof. Jonathan Fortney of the University of California at Santa Cruz.
“What is tremendously exciting to me is that this planet could be a real cousin of Venus and Earth.”
“We finally have a target to point our telescopes at, and can dig much deeper into the workings of a rocky exoplanet,” Dr Berta-Thompson concluded.
The discovery is reported November 12 in the journal Nature.
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