For the first time, astronomers have used NASA's James Webb Space Telescope to take a direct image of a planet outside our solar system. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable.
From: NASA/Goddard Space Flight Center
September 1, 2022 -- The
image shows how Webb's powerful infrared gaze can easily capture worlds beyond
our solar system, pointing the way to future observations that will reveal more
information than ever before about exoplanets.
The image, as seen
through four different light filters, shows how Webb's powerful infrared gaze
can easily capture worlds beyond our solar system, pointing the way to future
observations that will reveal more information than ever before about exoplanets.
"This is a
transformative moment, not only for Webb but also for astronomy
generally," said Sasha Hinkley, associate professor of physics and
astronomy at the University of Exeter in the United Kingdom, who led these
observations with a large international collaboration. Webb is an international
mission led by NASA in collaboration with its partners, ESA (European Space
Agency) and CSA (Canadian Space Agency).
The exoplanet in Webb's
image, called HIP 65426 b, is about six to 12 times the mass of Jupiter, and
these observations could help narrow that down even further. It is young as
planets go -- about 15 to 20 million years old, compared to our
4.5-billion-year-old Earth.
Astronomers discovered
the planet in 2017 using the SPHERE instrument on the European Southern
Observatory's Very Large Telescope in Chile and took images of it using short
infrared wavelengths of light. Webb's view, at longer infrared wavelengths,
reveals new details that ground-based telescopes would not be able to detect
because of the intrinsic infrared glow of Earth's atmosphere.
Researchers have been
analyzing the data from these observations and are preparing a paper they will
submit to journals for peer review. But Webb's first capture of an exoplanet
already hints at future possibilities for studying distant worlds.
Since HIP 65426 b is
about 100 times farther from its host star than Earth is from the Sun, it is
sufficiently distant from the star that Webb can easily separate the planet
from the star in the image.
Webb's Near-Infrared
Camera (NIRCam) and Mid-Infrared Instrument (MIRI) are both equipped with
coronagraphs, which are sets of tiny masks that block out starlight, enabling
Webb to take direct images of certain exoplanets like this one. NASA's Nancy
Grace Roman Space Telescope, slated to launch later this decade, will
demonstrate an even more advanced coronagraph.
"It was really
impressive how well the Webb coronagraphs worked to suppress the light of the
host star," Hinkley said.
Taking direct images of
exoplanets is challenging because stars are so much brighter than planets. The
HIP 65426 b planet is more than 10,000 times fainter than its host star in the
near-infrared, and a few thousand times fainter in the mid-infrared.
In each filter image,
the planet appears as a slightly differently shaped blob of light. That is
because of the particulars of Webb's optical system and how it translates light
through the different optics.
"Obtaining this
image felt like digging for space treasure," said Aarynn Carter, a
postdoctoral researcher at the University of California, Santa Cruz, who led
the analysis of the images. "At first all I could see was light from the
star, but with careful image processing I was able to remove that light and
uncover the planet."
While this is not the
first direct image of an exoplanet taken from space -- the Hubble Space
Telescope has captured direct exoplanet images previously -- HIP 65426 b points
the way forward for Webb's exoplanet exploration.
"I think what's
most exciting is that we've only just begun," Carter said. "There are
many more images of exoplanets to come that will shape our overall
understanding of their physics, chemistry, and formation. We may even discover
previously unknown planets, too."
https://www.sciencedaily.com/releases/2022/09/220901200644.htm
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