The James Webb Space Telescope has captured the
first direct image of a distant exoplanet, a world beyond our Solar System.
Webb has returned several pictures of the exoplanet
HIP 65426 b, a gas giant six to twelve times the mass of Jupiter located
roughly 385 light years from Earth, using a range of instruments.
The findings are part of an ongoing investigation
and have not yet been peer-reviewed or published in a scientific journal, but
Nasa announced them in a blog post Thursday morning.
"This is a pivotal moment, not only for Webb
but also for astronomy in general," said Sasha Hinkley, associate
professor of physics and astronomy at the University of Exeter. She is the
principal scientist in an international team studying exoplanets.
HIP 65426 b was discovered in 2017 by the European
Southern Observatory's Very Large Telescope in Chile, which observed the
exoplanet in short wavelengths of infrared light because longer wavelengths are
blocked by Earth's atmosphere for ground-based observatories. Because Webb is
in space, he has access to more of the infrared spectrum and can see more
details in distant planets.
Webb's images are not the first direct images of
exoplanets; the Hubble Space Telescope has captured images of other alien
worlds, but it is difficult to do so because the strong brightness of a
planet's neighbouring star can obscure the light from that exoplanet. HIP 65426
b, for example, is 10,000 times fainter than its star.
HIP 65426 b, on the other hand, orbits its star at a
distance 100 times greater than the Earth does the Sun, which helped
astronomers identify the planet in Webb's photographs. Webb's sensors also have
coronagraphs, which black out the disc of the distant star to reduce glare and
make detecting and focussing on an exoplanet easier.
“It was really impressive how well the Webb
coronagraphs worked to suppress the light of the host star,” Dr Hinkley said.
The photographs, captured with different filters and
Webb's Near-infrared camera (Nircam) and Mid-infrared instrument (Miri), are
just the beginning of what scientists anticipate will be a long series of
exoplanet observations and discoveries made possible by the new space
observatory. The photographs follow a fresh analysis of one of Webb's earliest
sightings, a spectrum of light from the exoplanet Wasp 39b, which confirmed the
presence of carbon dioxide in an extraterrestrial world's atmosphere for the
first time.
“I think what’s most exciting is that we’ve only
just begun,” University of California, Santa Cruz post doctoral researcher
Aarynn Carter, who analyzed the new Webb images of HIP 65426 b, said in a
statement. “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.”