The 'super-Earths',
with a mass 10 times greater than Earth's, are good candidates to find life
outside our solar system.
Located 42 light years
away, GJ 1214b is one of the most studied because it can be seen from
ground-based telescopes with relative ease
The data obtained with
the GTC by IAC researchers support the idea that GJ1214b's atmosphere is made
up of metal.
Sometimes important is
what is seen for what it is not observed. A team from the Institute de Astrophysical
de Canarias (IAC) has found that the atmosphere of the 'super-Earth' GJ 1214b,
one of the most known exoplanets that can be seen from Earth with certain
telescopes, it is characterized by an excess of hydrogen. The conclusion
obtained following observations in the Gran Telescope Canarias (GTC), supports
the idea that GJ 1214b has an atmosphere composed of elements of high
metallicity.
The study, published in
the journal Astronomy & Astrophysics, was led by researchers from the IAC
and Enrich Pale Murgas Felipe, who explain the reasons for initiating the
project: "Knowing the atmospheric composition of a planet is very
important because can reveal the physical conditions in the inner layers of
atmosphere. " This type of information is another step to ensure that in
the future, scientists can perform these analyzes in other 'super-Earths'
potentially habitable.
According Murgas
recounts, in the last 20 years has increased considerably the discovery of new
exoplanets-those detected outside our solar system, thanks to surveys or large
observational campaigns devoted to detection. Within this planetary zoo, a
group that raises more curiosity among astrophysicists: the 'super-Earths'.
These are planets that have a mass between 2 and 10 times that of Earth, a
range that is unmatched in the solar system. However, the resemblance to our
planet makes them "good candidates" for the search for life.
Perhaps one of the
'super-Earths' better known as GJ 1214b, discovered in 2009 about 42 light
years from Earth, "a close distance in galactic scale," said IAC
astrophysicist. However, his fame is not due to its distance from us but his
relationship with the star it orbits: because the relative size of the planet
from its star is greater than in other cases, it produces eclipses GJ 1214b
passing in front of its star cause a significant decrease in brightness that
comes from this and therefore observable with telescopes from Earth. "For
this reason, there have been numerous studies trying to identify some element
or molecule that can determine atmospheric composition," he adds.
However, despite the
efforts, "failed to detect any signal attributable to its
atmosphere." Pale Murgas and used the instrument of GTC OSIRIS tunable
filters to see if the exoplanet had an excess of hydrogen: "In particular,
we observe the spectral range where the line should appear atomic transition of
hydrogen known as Ha. If GJ 1214b having an atmosphere rich in water vapor,
this molecule may be destroyed at higher layers of the atmosphere due to the
radiation of the star, generating an excess of hydrogen. “Although there is
some margin of error, it seems that this is the case.
So what does the
absence of findings? For authors, is to support the theory that GJ 1214b has an
atmosphere composed of elements that produce a high metallicity constant
absorption wavelength. "If confirmed, the planet would be wrapped in a
blanket fog, preventing observe its surface. Just the opposite that on Earth,
"said Murgas. "The metallic elements may come from volcanic activity or
other mechanisms by which the planet initial atmospheric composition changes
over time," IAC astrophysicist concrete. In any case, he continues, the
work is a step further to reveal the true nature of GJ 1214b.
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