Using Hubble
and Spitzer space telescopes, scientists studied the "hot Saturn" called
WASP-39b - a hot, bloated, Saturn-mass exoplanet located about 700
light-years from Earth. By dissecting starlight filtering through the
planet's atmosphere into its component colors, the team found clear
evidence for a large amount of water vapor. In fact, WASP-39b has three
times as much water as Saturn does. Although the researchers predicted
they'd see water, they were surprised by how much they found. This
suggests that the planet formed farther out from the star, where it was
bombarded by a lot of icy material. Because WASP-39b has so much more
water than Saturn, it must have formed differently from our famously
ringed neighbor. Credits: NASA, ESA, G. Bacon and A. Feild (STScI), and
H. Wakeford (STScI/Univ. of Exeter) . › Larger view
Using Hubble
and Spitzer, astronomers analyzed the atmosphere of the "hot Saturn"
exoplanet WASP-39b, and they captured the most complete spectrum of an
exoplanet's atmosphere possible with present-day technology. By
dissecting starlight filtering through the planet's atmosphere into its
component colors, the team found clear evidence for water vapor.
Although the researchers predicted they would see water, they were
surprised by how much water they found - three times as much water as
Saturn has. This suggests that the planet formed farther out from the
star, where it was bombarded by icy material. Credits: NASA, ESA, G.
Bacon and A. Feild (STScI), and H. Wakeford (STScI/Univ. of Exeter). › Larger view
Much like detectives who study
fingerprints to identify the culprit, scientists used NASA's Hubble and Spitzer
space telescopes to find the "fingerprints" of water in the atmosphere of a
hot, bloated, Saturn-mass exoplanet some 700 light-years away. And, they found
a lot of water. In fact, the planet, known as WASP-39b, has three times as much
water as Saturn does.
Though no planet like this resides
in our solar system, WASP-39b can provide new insights into how and where
planets form around a star, say researchers. This exoplanet is so unique, it
underscores the fact that the more astronomers learn about the complexity of
other worlds, the more there is to learn about their origins. This latest
observation is a significant step toward characterizing these worlds.
Although the researchers predicted
they'd see water, they were surprised by how much water they found in this "hot
Saturn." Because WASP-39b has so much more water than our famously ringed
neighbor, it must have formed differently. The amount of water suggests that
the planet actually developed far away from the star, where it was bombarded by
a lot of icy material. WASP-39b likely had an interesting evolutionary history
as it migrated in, taking an epic journey across its planetary system and perhaps
obliterating planetary objects in its path.
"We need to look outward so we can
understand our own solar system," explained lead investigator Hannah Wakeford
of the Space Telescope Science Institute in Baltimore, and the University of
Exeter in Devon, United Kingdom. "But exoplanets are showing us that planet
formation is more complicated and more confusing than we thought it was. And
that's fantastic!"
Wakeford and her team were able to
analyze the atmospheric components of this exoplanet, which is similar in mass
to Saturn but profoundly different in many other ways. By dissecting starlight
filtering through the planet's atmosphere into its component colors, the team
found clear evidence for water. This water is detected as vapor in the
atmosphere.
Using Hubble and Spitzer, the team
has captured the most complete spectrum of an exoplanet's atmosphere possible
with present-day technology. "This spectrum is thus far the most beautiful
example we have of what a clear exoplanet atmosphere looks like," said Wakeford.
"WASP-39b shows exoplanets can have
much different compositions than those of our solar system," said co-author
David Sing of the University of Exeter. "Hopefully, this diversity we see in
exoplanets will give us clues in figuring out all the different ways a planet
can form and evolve."
Located in the constellation Virgo,
WASP-39b whips around a quiet, Sun-like star, called WASP-39, once every four
days. The exoplanet is currently positioned more than 20 times closer to its
star than Earth is to the Sun. It is tidally locked, meaning it always shows
the same face to its star.
Its day-side temperature is a
scorching 1,430 degrees Fahrenheit (776.7 degrees Celsius). Powerful winds
transport heat from the dayside around the planet, keeping the permanent nightside
almost as hot. Although it is called a "hot Saturn," WASP-39b is not known to
have rings. Instead, is has a puffy atmosphere that is free of high-altitude
clouds, allowing Wakeford and her team to peer down into its depths.
Looking ahead, Wakeford hopes to use
NASA's James Webb Space Telescope - scheduled to launch in 2019 - to get an
even more complete spectrum of the exoplanet. Webb will be able to give
information about the planet's atmospheric carbon, which absorbs light at
longer infrared wavelengths than Hubble can see. By understanding the amount of
carbon and oxygen in the atmosphere, scientists can learn even more about where
and how this planet formed.
The Hubble Space Telescope is a
project of international cooperation between NASA and ESA (European Space
Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the
telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts
Hubble science operations. STScI is operated for NASA by the Association of
Universities for Research in Astronomy, Inc., in Washington.
NASA's Jet Propulsion Laboratory,
Pasadena, California, manages the Spitzer Space Telescope mission for NASA's
Science Mission Directorate, Washington. Science operations are conducted at
the Spitzer Science Center at Caltech in Pasadena. Spacecraft operations are
based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are
archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech
manages JPL for NASA.
For more information about NASA's Hubble Space Telescope, visit: https://www.nasa.gov/hubble
For more information about NASA's Spitzer Space Telescope, visit: https://www.nasa.gov/spitzer
News Media Contact
Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-5011
calla.e.cofield@jpl.nasa.gov
Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu
