Study Findings: A Second Visit to Eps Ind Ab with JWST: New Photometry Confirms Ammonia and Suggests Thick Clouds in the Exoplanet Atmosphere of the Closest Super-Jupiter

Posted on by onespaceman2000
Image (Credit): Juno mission image of Jupiter taken on Juno’s 22nd close pass by Jupiter on Sept. 12, 2019. (NASA/JPL-Caltech/SwRI/MSSS / Image processing by Prateek Sarpal, © CC NC SA)

The Astrophysical Journal Letters abstract of study findings:

With JWST, we are directly imaging cold (∼200–300 K) solar-age giant exoplanets for the first time. At these temperatures, many molecular features appear, and water-ice clouds may condense and affect the emission spectrum; early photometric measurements of cold giant planets are already showing some tension with the predictions of cloud-free solar-metallicity atmosphere models. Here, we present new JWST/MIRI coronagraphic observations of the cold giant exoplanet Eps Ind Ab at 11.3 μm. Together with archival data, we use these new observations to study the atmosphere of this cold exoplanet, and we also refit its orbit, finding an updated mass of 7.6  ±  0.7MJup and an eccentricity of 0.24 +0.11/-0.08. The planet is significantly brighter (by 0.88  ±  0.08 mag) at 11.3 μm than at 10.6 μm, indicating the presence of ammonia. However, this ammonia feature is shallower than expected. This could indicate a low-metallicity or nitrogen-depleted atmosphere, but our preferred explanation is the presence of thick water-ice clouds that suppress the ammonia feature and the near-IR emission of Eps Ind Ab. Photometry of the small but growing sample of cold giant exoplanets demonstrates that they are consistently fainter than expected between 3 and 5 μm, consistent with the water-ice cloud hypothesis. 10.6 μm and 11.3 μm photometry of this cold exoplanet sample would be valuable to determine whether the suppressed ammonia feature is universal, and to frame a new open question about the underlying physical cause.

Citation: Elisabeth C. Matthews et al. a second visit to eps ind ab with JWST: new photometry confirms ammonia and suggests thick clouds in the exoplanet atmosphere of the closest super-Jupiter, ApJL 1002 L5 (2026).

DOI: 10.3847/2041-8213/ae5823

Study-related stories:

Max Planck Institute for Astronomy – “Cirrus Clouds Made of Water Ice May Surround a Jupiter-like Exoplanet”

Universe Today – “Webb Finds Water-Ice Clouds on Nearby Super-Jupiter”

Sci.News – “Webb Spots Icy Clouds on Distant Jupiter-Like Exoplane”

Pic of the Week: Multiple Views of Saturn

Posted on by onespaceman2000
Image (Credit):Two views of Saturn, one from NASA’s JWST and the second from the Hubble Space Telescope. (NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI))

This week’s images of Saturn from 2024 were just released by NASA. They show the planet in a variety of ways, depending on the telescope and instruments being used. The James Webb Space Telescope (JWST or Webb) and Hubble Space Telescope each have their own unique abilities that can bring the distant gas giant to life.

In its comments on the two images above, NASA noted:

Together, scientists can effectively ‘slice’ through Saturn’s atmosphere at multiple altitudes, like peeling back the layers of an onion. Each telescope tells a different part of Saturn’s story, and the observations together help researchers understand how Saturn’s atmosphere works as a connected three-dimensional system. Both complement previous observations done by NASA’s Cassini orbiter during its time studying the Saturnian system from 1997 to 2017...These 2024 observations, taken 14 weeks apart, show the planet moving from northern summer toward the 2025 equinox. As Saturn transitions into southern spring, and later southern summer in the 2030’s, Hubble and Webb will have progressively better views of that hemisphere.

Pic of the Week: Exposed Cranium Nebula

Posted on by onespaceman2000
Image (Credit): Side-by-side view of the Cranium nebula using two instruments on the JWST. You can see more stars and galaxies shining through with the NIRCam’s view, but you get a nice cosmic dust glows with the MIRI’s mid-infrared. (NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI))

This week’s images come from the James Webb Space Telescope (JWST). Each image shows a different view of the Cranium nebula depending on the JWST instrument being used. It is also called the “Exposed Cranium” Nebula because it looks like a brain in a see-through skull.

Here is a little more from NASA on what you are seeing above:

The nebula appears to have distinct regions that capture different phases of its evolution — an outer shell of gas that was blown off first and consists mostly of hydrogen, and an inner cloud with more structure that contains a mix of different gases. Both Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument) show a distinctive dark lane running vertically through the middle of the nebula that defines its brain-like look of left and right hemispheres. Webb’s resolution shows that this lane could be related to an outburst or outflow from the central star, which typically occurs as twin jets burst out in opposite directions. Evidence for this is particularly notable at the top of the nebula in Webb’s MIRI image, where it looks like the inner gas is being ejected outward.

Space Stories: More Artemis II Delays, Starliner a Type A Mishap, and James Webb Space Telescope Studies Atmosphere of Uranus

Posted on by onespaceman2000
Credit; NASA

Here are some recent space-related stories of interest.

—NPR: “NASA’s Artemis II Lunar Mission May Not Launch in March After All“

Just one day after NASA said it was eyeing a potential March 6 launch date for the Artemis II lunar mission, the space agency said Saturday that complications with the rocket could delay all launch attempts in March from the Kennedy Space Center in Florida...In a blog post, NASA said it is “taking steps to potentially roll back the Artemis II rocket and Orion spacecraft to the Vehicle Assembly Building,” after technicians observed an “interrupted flow of helium” to the rocket system. NASA says its teams are “actively reviewing data” and taking steps to “address the issue as soon as possible while engineers determine the best path forward.”

—Astronomy Magazine:“NASA Report Declares Starliner Incident a Type A Mishap“

On Thursday, NASA released sobering results from an independent investigation into the 2024 crewed Boeing Starliner test flight that left two astronauts stranded in space for months, placing blame not only on hardware failures, but the agency’s own leadership and culture. In a press conference, NASA Administrator Jared Isaacman said the agency had now categorized the incident as a type A mishap — the same classification applied to the Columbia and Challenger shuttle disasters — something he believes should have happened from the start.

—European Space Agency: “Webb Maps Uranus’s Mysterious Upper Atmosphere“

For the first time, an international team of astronomers have mapped the vertical structure of Uranus’s upper atmosphere, uncovering how temperature and charged particles vary with height across the planet. Using NASA/ESA/CSA James Webb Space Telescope’s NIRSpec instrument, the team observed Uranus for nearly a full rotation, detecting the faint glow from molecules high above the clouds. The results offer a new window into how ice-giant planets distribute energy in their upper layers.

Pic of the Week: Close-Up View of the Helix Nebula

Posted on by onespaceman2000
Image (Credit): Part of the Helix Nebula as captured by NASA’s James Webb Space Telescope. (NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI))

This week’s image from the James Webb Space Telescope (JWST) shows an up-close view of the Helix Nebula, which is about 650 light years away. Taken by the JWST’s Near-Infrared Camera, we see the colors of the gases moving away from the exploding star.

NASA notes:

Here, blistering winds of fast-moving hot gas from the dying star are crashing into slower moving colder shells of dust and gas that were shed earlier in its life, sculpting the nebula’s remarkable structure…A blazing white dwarf, the leftover core of the dying star, lies right at the heart of the nebula…Its intense radiation lights up the surrounding gas, creating a rainbow of features: hot ionized gas closest to the white dwarf, cooler molecular hydrogen farther out, and protective pockets where more complex molecules can begin to form within dust clouds. This interaction is vital, as it’s the raw material from which new planets may one day form in other star systems.

Below is a wider view of the nebula from which the image above is taken.

Image (Credit): The full view of the Helix Nebula, taken by the ground-based Visible and Infrared Telescope for Astronomy as well as the JWST’s more focused view. (ESO, VISTA, NASA, ESA, CSA, STScI, J. Emerson (ESO); Acknowledgment: CASU)