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The James Webb Space Telescope

 
 
 
NASA Webb Telescope on Twitter: "Hey now, Webb’s instruments are all-stars! 🌟

#ICYMI, Webb completed its mirror alignment phase! Each of its 4 instruments can now take clear images of the sky. Over the next 2 months, our team will calibrate the instruments to get Webb ready for science: (links)" / Twitter
Has some short video showing a bit of a team meeting.

Where Is Webb? NASA/Webb - shows the temperature graphs. All four instruments are at their target temperatures, the near-IR ones at 35 K and the mid-IR MIRI at 6.4 K.


The Hot and Cold of Webb – James Webb Space Telescope
The telescope's angle relative to the Sun is kept between 85d (pitch = -5d: hot) and 135d (pitch = +45d: cold). So it isn't the Milky Way that's the issue.

NASA Webb Telescope on Twitter: "It’s all about attitude 😤

As Webb points to different targets around the sky, the whole telescope moves together. Changes in Webb’s attitude — the angle of the Sun on its sunshield — can slightly heat or cool Webb. We test to measure those effects: (links)" / Twitter
 
Examining the Heart of Webb: The Final Phase of Commissioning – James Webb Space Telescope

"To complete commissioning, we will measure the detailed performance of the science instruments before we start routine science operations in the summer."

Then a detailed quote from the lead commissioning scientist for Webb, Scott Friedman of the Space Telescope Science Institute (STScI).

After stating the success in getting the instruments down to their operating temperatures,
We will now begin an extensive suite of calibrations and characterizations of the instruments using a rich variety of astronomical sources. We will measure the instruments’ throughput – how much of the light that enters the telescope reaches the detectors and is recorded. ...

The astrometric calibration of each instrument maps the pixels on the detectors to the precise locations on the sky, to correct the small but unavoidable optical distortions that are present in every optical system. ...

We will also measure the sharpness of the stellar images, what astronomers call the ‘point spread function.’ ...

We will test target acquisition for each instrument. ...

A final example of our instrument commissioning activities is observations of moving targets. ...

We are now in the last two months of Webb’s commissioning before it is fully ready for its scientific mission. ...
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Very comprehensive. The moving targets are Solar-System objects, moving noticeably fast across the background of stars. The Earth from the Sun moves at about 2.5 arcseconds per time minute, and that's rather sizable by JWST standards. The JWST's pointing accuracy is a few hundredths of an arcsecond, meaning that a target moving at that rate will cross the JWST's pointing accuracy in a time second.

As to the point spread function, to a first approximation, it has hexagonal spikes due to the hexagonal shape of the primary mirror. There are some weaker spikes due to the secondary-mirror support struts.
 
Webb's first "proper" images will start arriving in 41 days from now (July 12, 2022). For those who are interested I suggest you bookmark NASA's countdown page.

This set of images tracks the improvement of IR telescopes.

plneqgm84sw81.jpg


The last one is a teaser of what is to come once the JWST runs on full throttle and delivers high resolution images after the data have been processed down here.
 
MIRI’s Sharper View Hints at New Possibilities for Science – James Webb Space Telescope - showing JWST vs. Spitzer resolution.

NASA Webb Telescope on Twitter: "Computer, enhance! Compare the same target — seen by Spitzer & in Webb’s calibration images. Spitzer, NASA's first infrared Great Observatory, led the way for Webb’s larger primary mirror & improved detectors to see the infrared sky with even more clarity: (links)" / Twitter

NASA Webb Telescope on Twitter: "Webb’s image, taken by its MIRI instrument, features light from “polycyclic aromatic hydrocarbons." These molecules of carbon & hydrogen help us better understand the gas that exists between stars. Get ready for Webb to #UnfoldTheUniverse in unprecedented detail this summer! (pic link)" / Twitter

 Polycyclic aromatic hydrocarbon (PAH's) are benzene rings connected at their edges, with hydrogens at the overall edges. Graphene is a PAH sheet.

PAH's seem to be a common endpoint of biological-molecule degradation and of prebiotic synthesis.
 
Seventeen Modes to Discovery: Webb’s Final Commissioning Activities – James Webb Space Telescope

NASA Webb Telescope on Twitter: "Introducing the 17 keys to #UnfoldTheUniverse! 🔑

Learn how we're checking off Webb's 17 instrument modes and how they can apply to targets from Webb's first year of science, including deep fields, exoplanets, moons in our Solar System and more: (link)" / Twitter

NASA Webb Telescope on Twitter: "✅ Check please!
Before we can #UnfoldTheUniverse & start science, our team must test, calibrate, verify and sign off on each mode of operation for Webb’s 4 instruments. There are 17 instrument modes in total! Follow along on our “Where Is Webb?” tracker: (links)" / Twitter
noting
Where Is Webb? NASA/Webb
  • NIRCam: 4/5
  • NIRSpec:1/4
  • NIRISS: 4/4
  • MIRI: 3/4
  • Total: 12/17

Also on social media,
NASA Webb Telescope (@nasawebb) • Instagram photos and videos
 
Sophia Roberts again.
NASA Webb Telescope on Twitter: "Science rules! 😎
And for the Webb telescope, science wouldn't be possible without its instruments: NIRCam, NIRSpec, MIRI and FGS/NIRISS. Watch to learn how each will help us #UnfoldTheUniverse ⬇️ (vid link)" / Twitter


First Images From NASA’s Webb Space Telescope Coming Soon | NASA

NASA on Twitter: "You have a date with @NASAWebb. On July 12, the first full color images and data from the world's most powerful observatory will be revealed: (link)
It's time to #UnfoldTheUniverse. (vid link)" / Twitter


NASA Astrobiology: Exploring Life in the Universe on Twitter: "Researchers may have found a way that @NASAWebb can quickly identify nearby planets that could be promising for our search for life and worlds that are uninhabitable because their oceans have vaporized. More on this new oxygen hunting technique: (links)" / Twitter
noting
New Technique May Give NASA’s Webb Telescope a Way to Quickly Identify Planets with Oxygen | News | Astrobiology
As starlight passes through the exoplanet’s atmosphere, the oxygen absorbs certain colors (wavelengths) of light— in this case, infrared light with a wavelength of 6.4 micrometers. When oxygen molecules collide with each other or with other molecules in the exoplanet’s atmosphere, energy from the collision puts the oxygen molecule in a special state that temporarily allows it to absorb the infrared light. Infrared light is invisible to the human eye, but detectable using instruments attached to telescopes.

“Similar oxygen signals exist at 1.06 and 1.27 micrometers and have been discussed in previous studies but these are less strong and much more mitigated by the presence of clouds than the 6.4 micrometer signal,” said Geronimo Villanueva, a co-author of the paper at Goddard.

Intriguingly, oxygen can also make an exoplanet appear to host life when it does not, because it can accumulate in a planet’s atmosphere without any life activity at all. For example, if the exoplanet is too close to its host star or receives too much star light, the atmosphere becomes very warm and saturated with water vapor from evaporating oceans. This water could be then broken down by the strong ultraviolet radiation into atomic hydrogen and oxygen. Hydrogen, which is a light atom, escapes to space very easily, leaving the oxygen behind.

Over time, this process can cause entire oceans to be lost while building up a thick oxygen atmosphere. So, abundant oxygen in an exoplanet’s atmosphere does not necessarily mean abundant life, but may instead indicate a rich water history.
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Webb Nearly Set to Explore the Solar System – James Webb Space Telescope
Testing its Solar-System tracking on an asteroid, 6481 Tenzing, named after the first or the second to reach the top of Mt. Everest.

There is a lot that JWST may look at in the outer Solar System. Outer planets, their moons, their rings, asteroids, comets, ...

NASA Webb Telescope on Twitter: "Tracking a package? So did Webb! 📦
To prepare for upcoming solar system observations, Webb successfully completed its first test to track a moving object! Learn more about how Webb will explore the solar system to #UnfoldTheUniverse: (link)
📸: @NASAHubble (pic link)" / Twitter
 
Geology from 50 Light-Years: Webb Gets Ready to Study Rocky Worlds | NASA
Super-Hot Super-Earth 55 Cancri e

55 Cancri e orbits less than 1.5 million miles from its Sun-like star (one twenty-fifth of the distance between Mercury and the Sun), completing one circuit in less than 18 hours. With surface temperatures far above the melting point of typical rock-forming minerals, the day side of the planet is thought to be covered in oceans of lava.

...
Does 55 Cancri e Have a Thick Atmosphere?

One explanation for these observations is that the planet has a dynamic atmosphere that moves heat around

...
Or Is It Raining Lava in the Evening on 55 Cancri e?

Another intriguing possibility, however, is that 55 Cancri e is not tidally locked. Instead, it may be like Mercury, rotating three times for every two orbits (what’s known as a 3:2 resonance). As a result, the planet would have a day-night cycle.
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Mercury has a 3:2 spin-orbit resonance, but if 55 Cancri e has one, it may have a different one.

JWST will observe the planet directly, and since it observes in the IR, it will observe only a little bit of its star's light, and all of the planet's re-emission of its absorbed light.

NASA Webb Telescope on Twitter: "Is it possible for a rocky planet to be so hot that the surface is molten and the clouds rain lava? 🔥 ☂️
#NASAWebb will find out: (link)
📷: Artist illustration, credit NASA, ESA, CSA, Dani Player (STScI) (pic link)" / Twitter
 
Webb’s Quest for Primeval Black Holes – James Webb Space Telescope

Many galaxies contain supermassive black holes in their centers, BH's with masses millions to billions times the masses of stellar-collapse black holes.
An intriguing recent finding has been the discovery of hyper-massive black holes, with masses of several billion solar masses, already in place when the universe was only about 700 million years old, a small fraction of its current age of 13.8 billion years. This is a puzzling result, as at such early epochs there is not enough time to grow such hyper-massive black holes, according to standard theories. Some scenarios have been proposed to solve this conundrum. One possibility is that black holes, resulting from the death of the very first generation of stars in the early universe, have accreted material at exceptionally high rates. Another scenario is that primeval, pristine gas clouds, not yet enriched by chemical elements heavier than helium, could directly collapse to form a black hole with a mass of a few hundred thousand solar masses, and subsequently accrete matter to evolve into the hyper-massive black holes observed at later epochs. Finally, dense, nuclear star clusters at the centers of baby galaxies may have produced intermediate mass black hole seeds, via stellar collisions or merging of stellar-mass black holes, and then become much more massive via accretion.
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NASA Webb Telescope on Twitter: "What were the first black holes in the early universe like? Webb will look for them! They may be the seeds from which the massive black holes at the center of galaxies grew! (link)

⚫ Need a primer? Check out this black hole field guide! (links)" / Twitter
 
 
Webb: Engineered to Endure Micrometeoroid Impacts – James Webb Space Telescope

NASA Webb Telescope on Twitter: "In late May, Webb sustained a dust-sized micrometeroid impact to a primary mirror segment. Not to worry: Webb is still performing at a level that exceeds all mission requirements. Our first images will #UnfoldTheUniverse on July 12: (links)" / Twitter

NASA Webb Telescope on Twitter: "Micrometeoroid strikes are an unavoidable aspect of operating any spacecraft, and we expect that impacts will continue to occur throughout Webb’s lifetime. Our team built and tested the mirror on the ground anticipating such events. More details: (link)" / Twitter

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Scheduling Webb’s Science – James Webb Space Telescope

This can be tricky, since JWST's safe viewing area, its "field of regard", is a ring from 85d to 135d from the Sun's direction, a ring that moves as the JWST travels around the Sun.

NASA Webb Telescope on Twitter: "Once Webb is ready to #UnfoldTheUniverse, how do we plan out its schedule? 🗓️

With hundreds of programs selected for Webb's first year of science, a lot more goes into this process than you may think! Learn more from @SpaceTelescope expert Christine Chen: (links)" / Twitter
 
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Can't help but see that image and think of how poorly the "fine tuning" argument is for god. That is a tiny spec in the sky, and we see, what, hundreds of galaxies with billions and trillions of stars each?

Every dime in cost overrun, every day in delays, this scope was worth 100 times that.
 
First Images from the James Webb Space Telescope | NASA
Warning about the images: the colors are false colors, assigned to different wavelength bands of infrared light.

The galaxy cluster SMACS 0723 is about 4.6 billion light-years away, meaning that we see it at the time that the Solar System formed. The field of view on that image is described as the angular size of a grain of sand at arm's length, or about 1 mm / 1 m or 10-3 radian or 3.4 minutes of arc, close to human visual resolution.

About WASP-96's planet,
WASP-96 b is one of more than 5,000 confirmed exoplanets in the Milky Way. Located roughly 1,150 light-years away in the southern-sky constellation Phoenix, it represents a type of gas giant that has no direct analog in our solar system. With a mass less than half that of Jupiter and a diameter 1.2 times greater, WASP-96 b is much puffier than any planet orbiting our Sun. And with a temperature greater than 1000°F, it is significantly hotter. WASP-96 b orbits extremely close to its Sun-like star, just one-ninth of the distance between Mercury and the Sun, completing one circuit every 3½ Earth-days.

The combination of large size, short orbital period, puffy atmosphere, and lack of contaminating light from objects nearby in the sky makes WASP-96 b an ideal target for atmospheric observations.

On June 21, Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) measured light from the WASP-96 system for 6.4 hours as the planet moved across the star. The result is a light curve showing the overall dimming of starlight during the transit, and a transmission spectrum revealing the brightness change of individual wavelengths of infrared light between 0.6 and 2.8 microns.

While the light curve confirms properties of the planet that had already been determined from other observations – the existence, size, and orbit of the planet – the transmission spectrum reveals previously hidden details of the atmosphere: the unambiguous signature of water, indications of haze, and evidence of clouds that were thought not to exist based on prior observations.
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TEPCat: WASP-96 -- that star is much like the Sun, and its planet, b, orbits very close to it: distance 0.045 AU, period 3.425 days, equilibrium temperature 1300 K, hot enough to glow in visible light.
 
Hermit said:
Webb's first "proper" images will start arriving in 41 days from now (July 12, 2022). For those who are interested I suggest you bookmark NASA's countdown page.

This set of images tracks the improvement of IR telescopes.

plneqgm84sw81.jpg


The last one is a teaser of what is to come once the JWST runs on full throttle and delivers high resolution images after the data have been processed down here.
Click to expand...
Seems curious to me that the resolution of the middle and right image increases as the wavelength (?) decreases but the left image with the lowest wavelength has the worst resolution.
 
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