With more and more
discoveries happening all the time, the focus of exoplanet research
has begun to slowly shift from exoplanet discovery to exoplanet
characterization. Essentially, scientists are now looking to
determine the composition of exoplanets to determine whether or not
they could support life.
During a recent scientific conference, a team of scientists presented new research that indicates that water is likely to be a major component of those exoplanets which are between two to four times the size of Earth.
These findings will have
serious implications when it comes to the search for life beyond our
During a session titled "The Role of Extreme Atmospheric Escape from Hot Exoplanets", the team presented findings that indicated that water worlds may be more common than previously thought.
A new study suggests that planets that are
many times the mass and radius of Earth
could be water worlds.
Credit: David A. Aguilar (CfA)
As they indicated, the
Kepler mission has precisely measured the radii of over 4000
exoplanet candidates, along with their orbital periods and other
Combined with mass and recent radius measurements from the Gaia mission, the team was able to develop a model of these planets' internal structure.
Whereas planets that fall
into the former category are believed to be rocky, the latter ones
are generally thought to range from super-Earths to Neptune-sized
On these planets, roughly 50% of the mass consists of water, whereas water makes up just 0.2% of the Earth's mass.
As Dr. Zeng explained during the course of the presentation:
of a hypothetical ocean planet
with two natural satellites.
Credit: Wikipedia Commons
As Li explained, these "water worlds" are not so much rocky planets that are covered in deep oceans, but an entirely new type of planet for which there is no equivalent in the Solar System.
Perhaps even more surprising was just how common these planets appear to be.
According to their study,
Li and his colleagues indicated that about 35% of all known
exoplanets that are larger than Earth should be be water-rich.
What's more, they hypothesize that they likely formed in a way that
is similar to how the cores of gas giants are believed to have
formed - a rocky core surrounded by layers of volatile material made
solid by pressure.
But if this study is correct, then it appears that water is far more plentiful on exoplanets than previously though, and could be an impediment to life as we know it.
a water world where the sun-facing side
is able to maintain a liquid-water ocean.
Credit and Copyright:
Basically, the extreme heat and the a lack of access to sufficient sunlight, hydrothermal activity and land masses would make for a pretty hostile environment.
Nevertheless, the study
does offer some intriguing possibilities when it comes to
characterizing exoplanets and seeing what's out there.
This will then be
followed up on by ground-based telescopes - and the
soon-to-be-launched James Webb Space Telescope (JWST)
- which will provide spectroscopic measurements that will help
scientists characterize these planets' compositions and atmospheres.
In the meantime, there
are still plenty of rocky worlds out there to be explored for signs