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Astronomers from the CARMENES consortium (Calar Alto high-Resolution search for M nains with Exoearths with Near-infrared and Optical Scale Spectrographs) have detected a short-lived rocky planet orbiting the red dwarf Gliese 486.
Artist’s impression of the Gliese 486b super-Earth and its red dwarf star. Image credit: RenderArea, https://renderarea.com.
Gliese 486 is a dwarf M star located 26.3 light years from the constellation Virgo.
Also known as GJ 486, Wolf 437, LHS 341, and HIC 62452, the star is much weaker and cooler than the Sun.
The new planet revolves around the star once every 1.5 days at a distance of 2.5 million km.
Designated Gliese 486b, it belongs to a class of exoplanets called super-Earths.
It has a radius of 1.31 Earth rays, a mass 2.8 times that of our home planet, but has a similar density.
Its composition isn’t its only distinguishing feature – its relative proximity to Earth makes it an ideal candidate for observations with the next generation of astronomical technology.
An artist’s impression of the surface of Gliese 486b. Image credit: RenderArea, https://renderarea.com.
“The proximity of this exoplanet is exciting because it will be possible to study it in more detail with powerful telescopes such as the future James Webb Space Telescope and the various extremely large telescopes such as GMT and TMT,” said Dr Trifon Trifonov, astronomer at the Max-Planck-Institut für Astronomie.
“Over the next few years, we hope to use transit spectroscopy to look for signs of an atmosphere and eventually determine the composition of this planet’s surface.”
With an equilibrium surface temperature of 700 K (427 degrees Celsius, 801 degrees Fahrenheit), Gliese 486b is too hot to endure life as we know it.
“You couldn’t go out without some sort of space suit,” said Dr Ben Montet, an astronomer at the School of Physics at the University of New South Wales.
“Gravity is also 70% stronger than on Earth, which makes it harder to walk and jump. Someone who weighed 50kg on Earth would feel like they weighed 85kg on Gliese 486b. “
“If it had been a hundred degrees warmer, its entire surface would be lava, and its atmosphere would be vaporized rock,” said Dr José Antonio Caballero, astronomer at the Center for Astrobiology (CAB, CSIC- INTA).
“On the other hand, if Gliese 486b had been about a hundred degrees cooler, it would not have been suitable for follow-up observations.”
Astronomers detected Gliese 486b using data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and ground-based telescopes in Spain, the United States, Chile and Hawaii.
“This is the kind of planet we have dreamed of for decades,” said Dr Montet.
“We’ve known for a long time that rocky super-Earths must exist around nearby stars, but we didn’t have the technology to search for them until recently.”
The discovery is reported in an article published this week in the journal Science.
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T. Trifonov et al. 2021. A rocky exoplanet in transit nearby suitable for atmospheric investigation. Science 371 (6533): 1038-1041; doi: 10.1126 / science.abd7645
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