Scientists have uncovered strong evidence of a rocky exoplanet encased in a thick atmosphere, shattering long-held assumptions that small planets orbiting close to their stars can't sustain a dense blanket of gases.
Located about 280 light-years from Earth, TOI-561 b orbits an ancient G-type star and boasts a colossal magma ocean. A team of researchers employing NASA's Webb Space Telescope discovered the presence of this atmosphere, which significantly contributed to the planet's peculiar low density.
The discovery not only defies previous theories but also raises questions about how such a small planet can maintain a robust atmosphere in the face of intense radiation from its host star. The findings suggest that TOI-561 b may be "a wet lava ball" – an incredibly volatile-rich world where the interaction between its magma ocean and atmosphere serves as a delicate balance.
The team employed Webb's NIRSpec to measure the planet's day-side temperature, which should have reached scorching 4,900 degrees Fahrenheit if there was no atmosphere to insulate it. However, their observations revealed a surprising average temperature of 3,200 degrees Fahrenheit on the star-facing side – still extremely hot but not enough to account for the lack of an atmosphere.
To reconcile this discrepancy, researchers considered alternative explanations, including a thin layer of rock vapor on its surface, which would have a limited cooling effect. However, none of these theories stood up to scrutiny as well as the presence of a thick volatile-rich atmosphere.
According to Tim Lichtenberg, a researcher at the University of Groningen, this exoplanet must be "much, much more volatile-rich than Earth" to explain its observations. The equilibrium between the magma ocean and atmosphere is thought to be key to holding onto these gases, creating a fascinating paradox that scientists are eager to unravel.
Located about 280 light-years from Earth, TOI-561 b orbits an ancient G-type star and boasts a colossal magma ocean. A team of researchers employing NASA's Webb Space Telescope discovered the presence of this atmosphere, which significantly contributed to the planet's peculiar low density.
The discovery not only defies previous theories but also raises questions about how such a small planet can maintain a robust atmosphere in the face of intense radiation from its host star. The findings suggest that TOI-561 b may be "a wet lava ball" – an incredibly volatile-rich world where the interaction between its magma ocean and atmosphere serves as a delicate balance.
The team employed Webb's NIRSpec to measure the planet's day-side temperature, which should have reached scorching 4,900 degrees Fahrenheit if there was no atmosphere to insulate it. However, their observations revealed a surprising average temperature of 3,200 degrees Fahrenheit on the star-facing side – still extremely hot but not enough to account for the lack of an atmosphere.
To reconcile this discrepancy, researchers considered alternative explanations, including a thin layer of rock vapor on its surface, which would have a limited cooling effect. However, none of these theories stood up to scrutiny as well as the presence of a thick volatile-rich atmosphere.
According to Tim Lichtenberg, a researcher at the University of Groningen, this exoplanet must be "much, much more volatile-rich than Earth" to explain its observations. The equilibrium between the magma ocean and atmosphere is thought to be key to holding onto these gases, creating a fascinating paradox that scientists are eager to unravel.