For the second time, the James
Webb Space Telescope (JWST) searched for a dense atmosphere around an explants
named TRAPPIST-1c, located in one of the most interesting planetary systems
known, and this time the telescope did not produce a different result. From its
predecessor. On June 19, astronomers suggested that the aforementioned planet
does not have an atmosphere worthy of consideration, a result similar to the
result they reached regarding its neighbor, TRAPPIST-1 b, a few months ago.
There is no possibility that
one or more of the other five planets in the TRAPPIST-1 star system contain
dense atmospheres that contain biologically and geologically interesting
compounds, such as carbon dioxide, methane, and oxygen. However, it appears
that the two planets studied so far are devoid of any atmosphere, or almost
any.
Since planets of this type are
common around many stars, “these results of course reduce the number of
potentially habitable planets,” says Sebastian Tisa, a researcher specializing
in explants studies at the Max Planck Institute for Astronomy in Heidelberg,
Germany. The researcher and his colleagues presented these results in a study
published in the journal Nature .
Intense stellar radiation
The star “TRAPPIST-1” is about
12 parsecs (40 light-years) away from Earth, and seven planets revolve around
it, all of them rocky in surface, and the size of each one is approximately
equivalent to the size of Earth. Astronomers view this star system as one of
the best natural laboratories for studying how stars form and evolve, and what
factors might make them habitable. Therefore, these planets are main targets
for the telescope, which was launched in 2021, and has a power that enables it
to survey their atmospheres with greater accuracy, compared to other
observatories, such as the Hubble Space Telescope.
This planet's host star is a
faint, cool star, an M dwarf star, the most common type of star in the Milky
Way. The star emits ultraviolet radiation so intensely that it could wipe out
any atmosphere surrounding a nearby planet.
This star bombards the planet
closest to it, TRAPPIST-1b, with radiation equivalent to four times the
radiation reaching Earth from the Sun. Therefore, it was not surprising that
the James Webb Telescope found that it was a planet without any significant
atmosphere 2 . But the next planet, TRAPPIST-1C, has an orbit
farther from the star, increasing the chances that the slightly cooler planet
might have a denser atmosphere.
From this standpoint, the team
directed the telescope towards the “TRAPPIST-1” system four times during the
past months of October and November, which enabled scientists to calculate the
surface temperature of the planet “TRAPPIST-1C”, and they found that it reached
approximately 107 degrees Celsius on the side facing the star. This temperature
is too hot to allow the planet to maintain a dense atmosphere rich in carbon
dioxide.
A little water
By comparing observational
results with models of the planet's likely chemistry, scientists also
determined that the planet TRAPPIST-1c had a very small amount of water when it
formed, less than ten times the amount of water in Earth's oceans. The lack of
water when the planet was born, combined with the fact that it now lacks a
dense, carbon dioxide-rich atmosphere, indicates that the planet has always
lacked many of the elements needed to sustain life.
However, there is still hope
for other planets in the system. In a research paper 3 published on the arrive website, which specializes in publishing
research manuscripts, on June 8, Joshua Krisansen-Totton, a planetary scientist
at the University of Washington in Seattle, indicates the possibility that the
planets “E” and “F” contain The system - the fourth and fifth planets farthest
from the star - has a dense atmosphere, given that they are located at farther
distances from the star, enough for them to retain some of their water, unlike
the case of planets B and C.
We can say, in other words, that what scientists find
out about Planets B and C may not tell us much about the state of the
atmospheres of the more distant planets in the system. “I think it's reasonable
to say that we don't know what the chances of more distant planets having an
atmosphere will be,” Krisansen-Totton says.
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