IPB

Welcome Guest ( Log In | Register )

20 Pages V  « < 18 19 20  
Reply to this topicStart new topic
James Webb Space Telescope, information, updates and discussion
scalbers
post Mar 25 2023, 06:26 PM
Post #286


Senior Member
****

Group: Members
Posts: 1620
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 ]
Go to the top of the page
 
+Quote Post
StargazeInWonder
post May 11 2023, 02:33 PM
Post #287


Member
***

Group: Members
Posts: 216
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…
Go to the top of the page
 
+Quote Post
Quetzalcoatl
post Jun 1 2023, 04:01 PM
Post #288


Member
***

Group: Members
Posts: 102
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
Go to the top of the page
 
+Quote Post
Bill Harris
post Jun 28 2023, 06:17 PM
Post #289


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



Current Webb NIRCam images of Saturn:
Attached thumbnail(s)
Attached Image
 


--------------------
Go to the top of the page
 
+Quote Post
Bill Harris
post Jul 1 2023, 04:26 AM
Post #290


Senior Member
****

Group: Members
Posts: 2997
Joined: 30-October 04
Member No.: 105



And another recent Saturn image from Webb:

Attached thumbnail(s)
Attached Image
 


--------------------
Go to the top of the page
 
+Quote Post
Bill Harris
post Jul 3 2023, 04:25 PM
Post #291


Senior Member
****

Group: Members
Posts: 2997
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?
Attached thumbnail(s)
Attached Image
 


--------------------
Go to the top of the page
 
+Quote Post
StargazeInWonder
post Jul 3 2023, 05:45 PM
Post #292


Member
***

Group: Members
Posts: 216
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.
Go to the top of the page
 
+Quote Post
Bill Harris
post Jul 4 2023, 04:20 AM
Post #293


Senior Member
****

Group: Members
Posts: 2997
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


--------------------
Go to the top of the page
 
+Quote Post
StargazeInWonder
post Aug 3 2023, 09:59 PM
Post #294


Member
***

Group: Members
Posts: 216
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
Go to the top of the page
 
+Quote Post
Bill Harris
post Aug 5 2023, 03:42 AM
Post #295


Senior Member
****

Group: Members
Posts: 2997
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


--------------------
Go to the top of the page
 
+Quote Post
fredk
post Aug 5 2023, 11:49 PM
Post #296


Senior Member
****

Group: Members
Posts: 4245
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...).
Go to the top of the page
 
+Quote Post
scalbers
post Sep 22 2023, 09:52 PM
Post #297


Senior Member
****

Group: Members
Posts: 1620
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 ]
Go to the top of the page
 
+Quote Post
antipode
post Jan 25 2024, 05:17 AM
Post #298


Member
***

Group: Members
Posts: 314
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
Go to the top of the page
 
+Quote Post

20 Pages V  « < 18 19 20
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 10:59 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.