This is the first photo of an exoplanet taken by the James Webb Space Telescope.
“We’re actually measuring photons from the planet’s own atmosphere,” says astronomer Sasha Hinkley of the University of Exeter, UK. Seeing those light particles, “to me, it’s very exciting.”
The planet is about seven times the mass of Jupiter and more than 100 times further from its star than Earth is from the sun, Direct observations of the exoplanet HIP 65426 b programme. It is also young compared to Earth, which is more than 4 billion years old, about 10 or 20 million years old, Hinkley and colleagues report in a study submitted to arXiv.org on Aug. 31.
These three characteristics — size, distance, and youth — make HIP 65426 b relatively easy to see, and therefore a good planet to test the JWST’s ability to observe.And the telescope has Once again exceeded astronomers’ expectations (SN: 7/11/22).
“We’ve demonstrated how powerful the JWST is as an instrument for directly imaging exoplanets,” said exoplanet astronomer and co-author Aarynn Carter of the University of California, Santa Cruz.
astronomers discovered Over 5,000 planets orbit other stars (Serial Number: 3/22/22). But almost all of these planets are detected indirectly, either by the planets using their gravitational pull to tug at the star, or by blocking the starlight as they pass through the star and the telescope’s field of view.
To see a planet directly, astronomers must block the light from its star and let the planet’s own light shine, a tricky process.it is been complete forwardBut there are only about 20 planets in total (SN: 13 Nov 2008; SN: 14 Mar 2013; SN: 22 Jul 20).
“Nature has been very generous in every area of exoplanet discovery,” said MIT astrophysicist Sarah Seeger, who was not involved in JWST’s discovery. “It’s an area that nature doesn’t really go into.”
In 2017, astronomers discovered HIP 65426 b and imaged it directly using instruments on the Very Large Telescope in Chile. But because that telescope is on the ground, it can’t see all the light from the exoplanet. Earth’s atmosphere absorbs a lot of the planet’s infrared wavelengths — the wavelengths that JWST excels at. Space telescopes observed the planet on July 17 and July 30, capturing its glow at four different infrared wavelengths.
“These are wavelengths of light at which we’ve never seen exoplanets before,” Hinckley said. “I’ve been waiting for this day for six years. It feels amazing.”
Pictures at these wavelengths will help reveal how planets form and what their atmospheres are made of.
“Direct imaging is our future,” Seager said. “It was amazing to see Webb do so well.”
While the team has yet to study HIP 65426 b’s atmosphere in detail, it did Report the first spectrum – measuring light in different wavelength ranges – objects orbiting different stars. Spectroscopy can provide a deeper understanding of the object’s chemical composition and atmosphere, UC Santa Cruz astronomer Brittany Myers and colleagues report Sept. 1 in arXiv.org.
The object is called VHS 1256 b. It weighs 20 Jupiters, so it may be more of a transition between a planet and a star, called a brown dwarf, than a giant planet. JWST found evidence of an imbalance in carbon monoxide and methane levels in the sphere’s atmosphere. This means that the atmosphere is becoming chaotic, with winds or ocean currents pulling molecules from lower depths to the top and vice versa.The telescope also saw sand clouda common feature in brown dwarf atmospheres (SN: 7/8/22).
“It could be a violent and turbulent atmosphere full of clouds,” Hinckley said.
HIP 65426 b and VHS 1256 b are unlike anything we’ve seen in our solar system. They are more than three times the distance between Uranus and its star, suggesting that they formed in a completely different way than the more familiar planets. In future work, the astronomers hope to use the JWST to image smaller planets closer to their stars.
“All we want to do is start studying Earth, don’t we? We really want to get the first image of Earth orbiting another star,” Hinckley said. That’s probably beyond the scope of the JWST — Earth-sized planets are still too small. But Saturn? This might be something that JWST can focus on.