Surprising Atmosphere Of A Super
Surprising Atmosphere Of A Super
Using NASA’s James Webb Space Telescope, a team led by the Carnegie Institution was able to study TOI-561 b, an extremely hot rocky planet that orbits its star completely in just 10.56 hours.
The sudden presence of this planet’s atmosphere is a major challenge to old hypotheses about how very hot small planets evolve, which indicated that they lose their atmosphere quickly after they form.
A planet with extreme heat and harsh conditions
TOI-561 b is approximately twice the size of Earth, but it is completely different from it, as it orbits at a very close distance from its star, equivalent to a tenth of the distance between Mercury and the Sun, which makes one side of it always illuminated and daylight never disappears from it.
It was expected that such a small, hot planet would lose its atmosphere quickly.
“Based on what we know about other systems, such a planet was thought to be too small and too hot to retain its atmosphere for long after it formed,” explained study co-author Nicole Wallack.
She added: “But these observations turn the prevailing concepts about planets with very short orbital cycles upside down.”
Although the planet’s star is much older than the Sun, the planet’s atmosphere appears intact. This is partly due to TOI-561 b’s lower density compared to Earth, but it does not qualify as one of the large, gaseous, bloated planets known as “giant bulges.”
An ancient star and an unusual composition
The team studied whether the planet’s lower density is due to a small iron core and a lighter mantle, which is consistent with the properties of the host star.
Lead author Joanna Teske explained: “TOI-561 b is distinguished from other planets with very short orbital periods in that it orbits a very old, iron-poor star.”
Scientists believe that the planet formed in a chemical environment different from that of the planets in our solar system, making it a potential window into understanding the formation of planets in the early universe.
But internal structure alone does not explain all the observations, so the team suspected that a dense atmosphere makes the planet appear larger and less dense.
Thermal measurements reveal the atmosphere
The NIRSpec instrument aboard the James Webb Telescope helped test this idea, by measuring the temperature of the planet’s dayside during the secondary eclipse.
If the surface was exposed rock, the temperature was expected to reach about 4,900 degrees Fahrenheit (2,700 degrees Celsius), while actual measurements showed a temperature of only approximately 3,200 degrees (1,760 degrees Celsius), indicating the presence of active redistribution of heat.
The team explored several scenarios, such as the presence of a magma ocean or a thin layer of rock vapor, but none of them matched the data. The team concluded that the presence of a dense atmosphere is the only explanation for the observed cooling.
Co-author Anjali Peet explained: “Strong winds cool the day side of the planet by transferring heat to the night side, and gases such as water vapor absorb light before it escapes.”
She added that bright clouds may reflect starlight, which contributes to cooling the planet.
However, scientists still don’t know how the planet manages to maintain an atmosphere under such intense radiation.
Further analysis is currently underway to draw detailed temperature maps and improve understanding of the composition of the planet’s atmosphere.
The study was published in the journal Astrophysical Letters.
Source: interestingengineering
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Disclaimer: This news article has been republished exactly as it appeared on its original source, without any modification.
We do not take any responsibility for its content, which remains solely the responsibility of the original publisher.
Author: uaetodaynews
Published on: 2025-12-13 15:51:00
Source: uaetodaynews.com
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