Plot twist!
Astronomers thought this was the story of a star that expanded and engulfed its planet, but Webb data revealed a different means to the planet’s end. The planet’s orbit actually shrunk over millions of years, drawing it closer and closer to the star!
Near the end of the life cycle of a Sun-like star, it will swell outwards into a red giant. When that happens to our Sun, it will engulf the Earth - but don’t worry, that’s 5 billion years in our future. Astronomers thought they had witnessed this happening in a planetary system located about 12,000 light years from Earth. Then Webb got a look and its data showed that the planet’s orbit had actually shrunk over time! The Jupter-sized planet, located even closer to its star than Mercury is to our Sun, spiraled closer and closer, over millions of years, until it was ultimately engulfed.
How do we know? In the mid-infrared, Webb was able to determine that the star was not as bright as it should have been if it had actually evolved into a red giant. So no swelling. In the near-infrared, the region around the star was different in temperature and composition than expected as well. Even as we now know the planet’s actual fate, this data opens up more questions.
This diagram illustrates what this process might have looked like. Read more: science.nasa.gov/missions/webb/nasa-webbs-autopsy-of-plan...
Credit: NASA, ESA, CSA, STScI, R. Crawford (STScI)
Image description: A four panel illustration, with two boxes on the top row and two boxes on the bottom row. They are labeled: 1, 2, 3, 4. Panel 1 shows a host star, which looks like an orange globe with flares coming out on various sides. There is a blue line with arrows forming a spiral around the star. At 2 o’clock in the outer spiral, furthest away from the star, there is a blue planet. Panel 2 shows the same star and lines, but the planet is now at 7 o’clock and closer to the star. It is a little stretched out toward the star, appearing like an American football or rugby ball instead of a sphere. Panel 3 shows the same star and lines, but the planet is fully engulfed by the star, with big flares coming out where the planet and star collided. Panel 4 shows the aftermath, with a very transparent cloud of blue dust spread out from the star. A dark orange horizontal ring of material circles the host star. At lower left white text says "Artist Illustration."
Did you know that Webb can see small, nearby objects like asteroids?
Webb took a look at asteroid 2024 YR4, which we know is of no significant threat to Earth. The more we know about asteroids, the better we can protect our planet from space hazards. Webb was able to see the asteroid in two different ways: by detecting the heat given off by it in the mid-infrared, Webb directly measured its size. Webb’s near-infrared camera measured its reflected light, giving us information about its composition.
Read more: go.nasa.gov/4jf9cwz
This is the smallest object yet targeted by Webb - and also one of the smallest objects to have its size directly measured. Asteroid 2024 YR4 is approximately 60 meters (200 feet) long, about the height of a 15-story building.
Understanding what asteroids of this size are like helps inform the hazard they could pose to Earth. The thermal properties of a small asteroid (i.e. how quickly it heats up and cools down, how hot it is at its current distance from the Sun) differ from larger ones - likely a combination of its very fast spin and lack of fine-grained surface sand.
2024 YR4 is being studied by NASA’s planetary defense program and the International Asteroid Warning Network. Webb's unique data about its size has improved what we know about its orbit and trajectory. Combined with data from other telescopes, we are helping keep Earth safe!
Image credit: NASA, ESA, CSA, STScI, A. Rivkin (JHU APL)
Image description: A collage of three images primarily showing the black expanse of space. Two-thirds of the collage show one image of a black background sprinkled with stars and small, blurry galaxies in orange, blue, and white. On the right side of the main image, not far from the top, a very faint dot is outlined with a white square. Two images at right, in a column show zoomed in views of this area. The top box is labeled NIRCam and shows a fuzzy dot at the center. The bottom box is labeled MIRI and shows a fuzzy pinkish dot at the center.
What does star formation look like in extreme environments? 🌟
Webb took a peek at Sagittarius C, a star-forming region located in the heart of our galaxy near the supermassive black hole at its core. Stars typically form in clouds of dust and gas - which there are plenty of near the galaxy’s center - so why aren’t we seeing many stars born there? Webb’s data is showing that the strong magnetic fields that surround our central black hole may be playing a role in suppressing star formation.
Pictured here is data from the ground-based radio observatory, MeerKAT. The inset is Webb’s infrared image of a small region of this much larger area. The MeerKAT image spans 1,000 light-years, while the Webb image covers only 44 light-years. At the center of the MeerKAT image, the region surrounding the Milky Way’s supermassive black hole blazes bright. Huge vertical filamentary structures echo those captured on a smaller scale by Webb in Sagittarius C’s blue-green hydrogen cloud. Like a super-long exposure photograph, MeerKAT shows the bubble-like remnants of supernovas that exploded over millennia, capturing the dynamic nature of the Milky Way’s chaotic core.
Read more: go.nasa.gov/3FSFAqi
Credit: NASA, ESA, CSA, STScI, SARAO, Samuel Crowe (UVA), John Bally (CU), Ruben Fedriani (IAA-CSIC), Ian Heywood (Oxford)
Image description: Processed data collected by the MeerKAT radio telescope shows the plane of the Milky Way galaxy, with a graphic pullout highlighting a much smaller region on the right, captured by the James Webb Space Telescope’s near-infrared light observations. The MeerKAT image is colored in blue, cyan, and yellow, with a very bright white-yellow center that indicates the location of the Milky Way’s supermassive black hole. Painterly bubbles of various sizes, clouds, and vertical brushstroke-like streaks make up the radio image. The Webb inset shows stars and gas clouds in red, with an arching cloud of bright cyan that contains many straight, needle-like features that appear more crystalline than cloudy.
Tags: Sagittarius A star Sagittarius C Milky Way Center
The universe also has eras!
Webb observed a surprising and extremely distant galaxy that existed 330 million years after the big bang, during what we call the universe’s “era of reionization.” This galaxy was emitting ultraviolet light at a specific wavelength that would typically have been absorbed by neutral hydrogen atoms prevalent at this point in the universe’s history. During the era of reionization, this neutral hydrogen was gradually ionized by the ultraviolet light emitted by newly forming stars. This is an ongoing process over hundreds of millions of years - and at just 330 million years after the big bang, there should still have been enough neutral hydrogen to shield this galaxy from Webb’s view - and yet Webb saw a strong signal from it.
(How did an infrared telescope see this galaxy emitting ultraviolet light? This galaxy is so distant that its light has been shifted towards the redder end of the electromagnetic spectrum by the expansion of the universe. As the space between objects stretches, any light in that space will also stretch. This effect is called redshift - and is why this galaxy’s ultraviolet light was perceived by us to be infrared.)
The implications of Webb seeing a signal from this galaxy are that perhaps the reionization process of neutral hydrogen started earlier than scientists think it did. Or perhaps there were some unexpectedly powerful sources of ionizing radiation early on in the galaxy’s history. What exactly those sources could be (maybe the much sought-after earliest generation of stars?) is still a mystery.
Read more: go.nasa.gov/3XCIUfk
Credit: NASA, ESA, CSA, Brant Robertson (UC Santa Cruz), Ben Johnson (CfA), Sandro Tacchella (Cambridge), Phill Cargile (CfA), Joris Witstok (Cambridge, University of Copenhagen), P. Jakobsen (University of Copenhagen), Alyssa Pagan (STScI), Mahdi Zamani (ESA/Webb), JADES Collaboration
Image description: A two panel image. At left, hundreds of tiny galaxies are scattered across the black background of space. A small portion of the sky near the bottom is outlined with a white box. Lines extend from the corners of the box to the right panel. At right, a small red dot at the middle is highlighted with white lines and labeled redshift z = 13. At upper left, a face-on spiral galaxy is labeled z = 0.63. At lower right, an edge-on spiral galaxy is labeled z = 0.70. A handful of other small background galaxies are seen against the black background of space. At lower right, the panel is labeled JADES-GS-z-13-1.
Tags: JADES
Expand your imagination 🍥
What appears to be a single galaxy is actually two that are very far apart! The closer galaxy lies in the center of the image, while the more distant galaxy appears to be wrapped around it in a phenomenon we call an “Einstein ring.”
Einstein rings occur when light from a distant galaxy gets bent by the gravity of a massive closer-by object, in this case another galaxy. The light from the distant galaxy that would otherwise travel in a straight line follows the bend of gravitationally warped spacetime, brightening the light from behind the galaxy and acting as a sort of natural magnifying glass. Einstein predicted this effect in his theory of relativity.
Read more: esawebb.org/images/potm2503a/
Credit: ESA/Webb, NASA & CSA, G. Mahler Acknowledgement: M. A. McDonald
Image description: In the center is an elliptical galaxy, seen as an oval-shaped glow around a small bright core. Around this is wrapped a broad band of light, appearing like a spiral galaxy stretched and warped into a ring, with bright blue lines drawn through it where the spiral arms have been stretched into circles. A few distant objects are visible around the ring on a black background.