⭐ Group huddle ⭐️
Until Webb, it was a challenge to observe star clusters in the dense central area of our Milky Way — which bulges out, full of old stars and dust! Here’s Webb’s view of NGC 6440.
Orbiting within the Galactic bulge, 28,000 light years away, NGC 6440 is a globular cluster. Globular clusters are full of older stars (hundreds of thousands to millions of them!) tightly bound together by gravity.
Learn more: esawebb.org/images/potm2404a/
[Image description: A spherical collection of stars which fills the whole view. The cluster is dominated by a concentrated group of bright white stars at the center, with several large yellow stars scattered throughout the image. Many of the stars have visible diffraction spikes. The background is black.]
Credit: ESA/Webb, NASA & CSA, P. Freire; Acknowledgement: M. Cadelano and C. Pallanca
Tags: JWST NASA Stars Globular Cluster NGC 6440 Space Universe Astronomy NGC 6440
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One side of planet WASP-43 b is constantly illuminated by its star, the other in permanent darkness. Webb tells us this gas giant is clear on its dayside and cloudy on its nightside, with equatorial winds of 5,000 miles per hour.
WASP-43 b is what is known as a hot Jupiter: smaller than Jupiter, made primarily of hydrogen and helium, and hotter than any of our solar system’s gas giants. This planet orbits its small, cool star closely at 1/25th the distance between Mercury and the Sun, making it tidally locked.
Previously, Hubble showed water vapor on the dayside, and along with Spitzer, suggested clouds on the nightside. Webb's precise data demonstrates clear signs of water vapor on both sides of WASP-43 b, and provides new information about temperature, cloud cover, winds, and atmospheric composition.
One surprising discovery: Scientists expected to see methane on WASP-43 b’s nightside, yet none could be found. The team believes high wind speeds (of 5,000 miles per hour or more) could be the cause — moving gas around the planet too fast for chemical reactions to produce detectable amounts of methane. Learn more: science.nasa.gov/missions/webb/nasas-webb-maps-weather-on...
Artist Concept Credit: NASA, ESA, CSA, Ralf Crawford (STScI)
Image Description: Illustration showing a hazy blue planet against the black background of space. The planet is in the left side of the frame. The axis is tilted roughly 20 degrees counter-clockwise from vertical. The eastern side (right half) is lit by a star out of view and the western side (left half) is in shadow. The terminator (the boundary between the day and night sides) is fuzzy. There are white patchy clouds visible on the dayside, near the terminator, along the equator, that appear to be originating from the nightside.
Tags: jwst nasa webb james webb space telescope exoplanet WASP-43 b
This light curve shows the change in brightness of the WASP-43 system over time as the planet orbits the star. This type of light curve is known as a phase curve because it includes the entire orbit, or all phases of the planet.
Because it is tidally locked, different sides of WASP-43 b rotate into view as it orbits. The system appears brightest when the hot dayside is facing the telescope, just before and after the secondary eclipse when the planet passes behind the star. The system grows dimmer as the planet continues its orbits and the nightside rotates into view. After the transit when the planet passes in front of the star, blocking some of the starlight, the system brightens again as the dayside rotates back into view.
This graph shows more than 8,000 measurements of 5- to 12-micron mid-infrared light captured over a single 24-hour observation using the low-resolution spectroscopy mode on Webb’s MIRI (Mid-Infrared Instrument). By subtracting the amount of light contributed by the star, astronomers can calculate the amount coming from the visible side of the planet as it orbits. Webb was able to detect differences in brightness as small as 0.004% (40 parts per million).
Since the amount of mid-infrared light given off by an object is directly related to its temperature, astronomers were able to use these measurements to calculate the average temperature of different sides of the planet.
Learn more: science.nasa.gov/missions/webb/nasas-webb-maps-weather-on...
Credits:
Illustration: NASA, ESA, CSA, Ralf Crawford (STScI)
Science: Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)
Image Description: Graphic titled Hot Gas-Giant Exoplanet WASP-43 b: Phase Curve 1 ¼ Orbits; MIRI Low-Resolution Spectroscopy. y-axis: Brightness of Planet + Star (5 to 12 micron emitted light), ranging from dimmer at bottom to brighter at top. x-axis: Elapsed Time (Hours) ranging from 0 to 24 in increments of 4. Thousands of orange data points form a thick, clear pattern, with no outliers and very little scatter. Curve forms a subtle sine wave with crests from 2-4 hours and 20-24 hours, and trough in the middle from 10-14 hours. Curve interrupted by 3 prominent U-shaped valleys: 2 shallow valleys at the wave crests at 2 hours and 22 hours, and a very deep valley in the middle of the trough at 12 hours. The base of the shallow valleys at 2 and 22 hours are labeled “starlight only,” with tops of valley walls on either side labeled “dayside + star.” Center of deep valley at 12 hours is labeled “nightside + partially-blocked star,” with tops of valley walls on either side labeled “nightside + star.”
Tags: jwst nasa webb james webb space telescope exoplanet WASP-43 b
This set of maps shows the temperature of the visible side of the hot gas-giant exoplanet WASP-43 b, as the planet orbits its star.
The temperatures were calculated based on more than 8,000 brightness measurements of 5- to 12-micron mid-infrared light detected from the star-planet system by MIRI (the Mid-Infrared Instrument) on NASA’s James Webb Space Telescope. In general, the hotter an object is, the more mid-infrared light it gives off.
Because WASP-43 b orbits so close to its star (about 1.3 million miles, or 0.014 astronomical units), it is tidally locked: One side faces the star at all times, receiving continuous radiation, while the other faces away from the star in permanent darkness. This results in a clear temperature difference between the dayside and nightside. The amount of infrared light detected from the planet is greatest when the hot dayside faces the telescope, just before and after it passes behind the star (a phenomenon known as a secondary eclipse). The planet appears much dimmer in infrared light when the cooler nightside faces the telescope, as it moves across the star (the transit).
The exact difference in temperature, however, also depends on factors such as wind speeds and cloud cover. Based on the MIRI observations, WASP-43 b has an average temperature of about 2,280°F (1,250°C) on the dayside and 1,115°F (600°C) on the nightside. This is consistent with strong winds that carry heat around from the dayside to the nightside, and the presence of nightside clouds that prevent heat energy from escaping to space.
The temperature maps were made by carefully analyzing the change in temperature as different parts of the planet rotate into and out of view. The research indicates that the hottest point on the planet is not the point that receives the most light from the star (the substellar point, where the star is straight above in the sky). Instead, it is shifted about 7 degrees eastward. (This is why the maps look slightly off-center.) This is a result of strong equatorial winds, which blow at speeds upwards of 5,000 miles per hour, moving the hot air horizontally before it can radiate energy back out to space.
Learn more: science.nasa.gov/missions/webb/nasas-webb-maps-weather-on...
Credits:
Illustration: NASA, ESA, CSA, Ralf Crawford (STScI)
Science: Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)
Image Description: Graphic titled “Hot Gas-giant Exoplanet WASP-43 b: Temperature Maps; MIRI Low-Resolution Spectroscopy” showing purple to yellow temperature maps of planet’s telescope-facing hemisphere at 4 orbital positions. Gray line with arrows pointing counterclockwise forms orbital path around star. Temperature scale at lower left, labeled in °F and K, grades from purple at left to yellow at right: 1,000°F is purple; 1,500°F pink; 2,000°F orange; 2,500°F yellow. 1,000 K dark pink. 1,500 K orange-yellow. Planet behind star, labeled “Permanent Dayside”: Hemisphere is yellow in center, grading to orange at edges. Planet left of star: Color grades from yellow at right edge facing star to purple at left edge facing away. Planet in front of star, labeled “Permanent Nightside” is purple slightly right of center, grading to dark pink at edges. Planet right of star: Color grades from yellow at left edge facing star to purple at right edge facing away.
Tags: jwst nasa webb james webb space telescope exoplanet WASP-43 b
This image showcases three views of one of the most distinctive objects in our skies, the Horsehead Nebula. This object resides in part of the sky in the constellation Orion (The Hunter), in the western side of the Orion B molecular cloud. Rising from turbulent waves of dust and gas is the Horsehead Nebula, otherwise known as Barnard 33, which resides roughly 1300 light-years away. The first image (left), released in November 2023, features the Horsehead Nebula as seen by ESA's Euclid telescope. Euclid captured this image of the Horsehead in about one hour, which showcases the mission's ability to very quickly image an unprecedented area of the sky in high detail. You can learn more about this image here. The second image (middle) shows the NASA/ESA Hubble Space Telescope's infrared view of the Horsehead Nebula, which was featured as the telescope's 23rd anniversary image in 2013. This image captures plumes of gas in the infrared and reveals a beautiful, delicate structure that is normally obscured by dust. You can learn more about this image here. The third image (right) features a new view of the Horsehead Nebula from the NASA/ESA/CSA James Webb Space Telescope's NIRCam (Near-InfraRed Camera) instrument. It is the sharpest infrared image of the object to date, showing a part of the iconic nebula in a whole new light, and capturing its complexity with unprecedented spatial resolution. You can learn more about this image here: webbtelescope.org/contents/media/images/2024/119/01HV6MPV...
Credits: NASA, ESA, CSA, Karl Misselt (University of Arizona), Alain Abergel (IAS, CNRS), Mahdi Zamani The Euclid Consortium, Hubble Heritage Project (STScI, AURA)
[Image description: A collage of three images of the Horsehead Nebula. In the left image labelled "Euclid (Visible-Infrared)", the Nebula is seen amongst its surroundings. A small box around it connects to the second image labelled "Hubble (Infrared)", where the Nebula is zoomed in on. A portion of the Nebula's head has another box, which leads with a callout to the third image, labelled "Webb (Infrared)", of that area.]
Tags: Barnard 33 Horsehead Nebula jwst webb james webb space telescope