James Webb Space Telescope, information, updates and discussion |
James Webb Space Telescope, information, updates and discussion |
Mar 25 2023, 06:26 PM
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#286
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Senior Member Group: Members Posts: 1669 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
Silicate clouds in a hot Jupiter via this news release:
https://webbtelescope.org/contents/news-rel...3/news-2023-105 -------------------- Steve [ my home page and planetary maps page ]
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May 11 2023, 02:33 PM
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#287
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Member Group: Members Posts: 251 Joined: 14-January 22 Member No.: 9140 |
The Cycle 2 observation plans are taking shape. General Observers approvals are listed here:
https://www.stsci.edu/jwst/science-executio...vers/cycle-2-go It's impossible to summarize this succinctly, but I'll note a few: A plan to coordinate JWST observations of Io with one of Juno's close passes. Comprehensive spectra of Europa such as JWST can perform. Observations of Jupiter Trojans. Attempt to characterize Enceladus's plumes. More TRAPPIST-1 plans (but not so many as in Cycle 1, it seems?). Attempt to characterize the rocky surface of terrestrial planet LHS 3844 b. Attempt to characterize the galaxy farthest known before JWST. And hundreds more… |
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Jun 1 2023, 04:01 PM
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#288
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Member Group: Members Posts: 104 Joined: 3-February 20 From: Paris (France) Member No.: 8747 |
Bonsoir,
It's probably not lost on you, but the news still belongs here. JWST detects a huge plume rising from Enceladus https://www.nasa.gov/feature/goddard/2023/w...-moon-enceladus Nicolas Biver * made this remark on a French forum, and I quote: "It's just one more resolute observation between those made by Cassini and Herschel more than 10 years ago, which showed that encelade was ejecting ~8x10^27 water molecules per second (250 kg or liter/s) to feed a torus of water vapor ~50000km in cross-section diameter and encompassing encelade's orbit (238000 km in circumference. So whether it's the distance LosAngeles - Buenos-Aires when it's just the tip of the iceberg... whose total diameter exceeds the Earth-Moon distance,.... it's all a question of knowing which part of the water vapor cloud we're talking about! As the JWST pixel (in the IR) is much smaller than Herschel's, the image of the water vapor cloud is more resolute." *N. Biver : Doctorate in astrophysics, having participated, among other things, in the European Rosetta space mission |
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Jun 28 2023, 06:17 PM
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#289
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Senior Member Group: Members Posts: 3009 Joined: 30-October 04 Member No.: 105 |
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Jul 1 2023, 04:26 AM
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#290
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Senior Member Group: Members Posts: 3009 Joined: 30-October 04 Member No.: 105 |
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Jul 3 2023, 04:25 PM
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#291
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Senior Member Group: Members Posts: 3009 Joined: 30-October 04 Member No.: 105 |
A Webb Uranus image from April 2023.
And what do we make of that bright, bright cloud at 8:30 on the limb? -------------------- |
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Jul 3 2023, 05:45 PM
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#292
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Member Group: Members Posts: 251 Joined: 14-January 22 Member No.: 9140 |
It's important to remember how sensitive these details are to the choice of wavelength, and comparing JWST images to those from other, seemingly-comparable telescopes, and be misleading, and I think this is actually a great example of it.
Uranus is very dark in certain IR wavelengths that are absorbed by methane. Among the many wavelengths available to JWST, the rings are comparatively much brighter in some of those, and high, "white" clouds may also be much brighter. The ratios can be much more dramatic than in images from Voyager, Hubble, or Keck. And I think that's the real story here. Probably nothing here is actually different from what was going on with Uranus at the time that images were being captured by Hubble and Keck, but the IR is showing us something very different. And then the people who are making the aesthetic choices in how to present the imagery are maybe doing something subtly deceptive by producing outputs that almost resemble the way we've been used to seeing Uranus and Neptune with these rare, isolated differences. |
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Jul 4 2023, 04:20 AM
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#293
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Senior Member Group: Members Posts: 3009 Joined: 30-October 04 Member No.: 105 |
I am well aware of Webb's multispectral IR capability, and so forth, but it impressed me that this cloud was bright enought to cause diffraction spikes. In the Neptune image there is a cloud at 5:30 that may be be forming spikes, but they are indistinct. In the Jupiter image the somewhat linear polar aurorae are forming a diffraction spike at 90 and 270*. So despite the choice of colors used to create this image and how this image was processed, the presence of the spikes certainly suggests that this cloud is intrinsically bright.
--Bill -------------------- |
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Aug 3 2023, 09:59 PM
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#294
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Member Group: Members Posts: 251 Joined: 14-January 22 Member No.: 9140 |
I know that cosmology and galaxies and so on is not the center of gravity of this board's discussion topics, but here's a nice overview of what JWST has been revealing about the early universe.
The TL;DR is: It looks like stars and galaxies evolved significantly faster at the beginning of the universe than theories had previously estimated, but not so much faster that everything we thought we knew was necessarily wrong. https://www.pnas.org/doi/10.1073/pnas.2311963120 |
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Aug 5 2023, 03:42 AM
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#295
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Senior Member Group: Members Posts: 3009 Joined: 30-October 04 Member No.: 105 |
Stargaze, the current Cosmological model is based on our best interpretation(s) of available data. I fully expected Webb to expand that data and I anticipate that our model(s) will be changing.
--Bill -------------------- |
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Aug 5 2023, 11:49 PM
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#296
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
Yeah, that's certainly true of the messier stuff, like galaxy formation, which depends on all sorts of details like feedback and interactions. It's complicated enough that you can't just write down what will happen based on the fundamental laws of physics - you have to make all sorts of assumptions/guesses about what's important. No doubt Webb will help a lot there.
The bigger picture of cosmology (baryons, dark matter/energy, flatness, GR; what's usually referred to as "the cosmological model") is much more secure (apart from that niggly Hubble tension...). |
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Sep 22 2023, 09:52 PM
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#297
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Senior Member Group: Members Posts: 1669 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
CO2 ice detected on the surface of Europa:
https://www.nasa.gov/feature/goddard/2023/n...r-s-moon-europa -------------------- Steve [ my home page and planetary maps page ]
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Jan 25 2024, 05:17 AM
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#298
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Member Group: Members Posts: 316 Joined: 1-October 06 Member No.: 1206 |
Candidate giant exoplanets around metal polluted white dwarfs.
https://arxiv.org/pdf/2401.13153.pdf Given that only 4 WDs were in the survey and they found 2 candidates, this potentially represents to first of many similar discoveries. WD planets have been elusive - maybe not any more! P |
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