Ocean planet discovered 100 ly from Earth

[Halbhh]

Wasn’t this discussion about reproducing colour as perceived by the human eye by using a transformation on the pixel data?

We did have a side topic for a while about the JWST images being assigned colors, because it wasn't what some had expected, and I tried to explain it in a clear and simple way without technical stuff or math, etc.

(imo, the more interesting thing in this thread is the water planet being discussed from the OP, btw.)

You can “un-redshift” by applying the conversion factor 1/(1+z) to each pixel in the image where z is the redshift value.

Yes. That's what I was pointing out without the math.

The JWST data however is in monochrome

Yep, though of course it's not hard if the aim is to have more colors to merely combine many different images at different filter wavelengths. I'm guessing you'd already know that(?), as would many who follow astronomy much.

If you attempt to apply the 1/(1+z) transformation to the final colour image unfortunate consequences such as green coloured stars or galaxies can occur.

While that seemed kinda trivial to me actually, as I was explaining in my posts above (non mathematically) that one could try to get a rough simulation of what a very high redshift galaxy (not individual stars) might look like when observed at a transformed to lower redshift where the main peak would be in our visual range, and one would of course merely shift until it was at a redshift that was visually interesting....sorta an arbitrary amount...(this may be redundant explanation, but in other words, you pick the colors by picking how much you shift it, so if you don't like green, why do green?)

It's fun to consider on the other hand as just a curiosity an entirely different kind of image where individual stars could be seen, but of course individual stars are not visible at high redshifts. Individual stars, even the brightest, are only visible at a vastly closer distance, and thus very much lower redshift to begin with. Did I leave out above I was talking about high redshift, that is, near the limits of what is possible for JWST to see, galaxies that were very early on in the Universe? I bet I didn't say that clearly enough above. ah...

What's up for you today? What's interesting that you're looking at lately?

 

[sjastro]

We did have a side topic for a while about the JWST images being assigned colors, because it wasn't what some had expected, and I tried to explain it in a clear and simple way without technical stuff or math, etc.

(imo, the more interesting thing in this thread is the water planet being discussed from the OP, btw.)

Yes. That's what I was pointing out without the math.

Yep, though of course it's not hard if the aim is to have more colors to merely combine many different images at different filter wavelengths. I'm guessing you'd already know that(?), as would many who follow astronomy much.


While that seemed kinda trivial to me actually, as I was explaining in my posts above (non mathematically) that one could try to get a rough simulation of what a very high redshift galaxy (not individual stars) might look like when observed at a transformed to lower redshift where the main peak would be in our visual range, and one would of course merely shift until it was at a redshift that was visually interesting....sorta an arbitrary amount...(this may be redundant explanation, but in other words, you pick the colors by picking how much you shift it, so if you don't like green, why do green?)

It's fun to consider on the other hand as just a curiosity an entirely different kind of image where individual stars could be seen, but of course individual stars are not visible at high redshifts. Individual stars, even the brightest, are only visible at a vastly closer distance, and thus very much lower redshift to begin with. Did I leave out above I was talking about high redshift, that is, near the limits of what is possible for JWST to see, galaxies that were very early on in the Universe? I bet I didn't say that clearly enough above. ah...

You won’t even get a rough simulation for colour as perceived by the human eye as light in the infrared range is mapped into the R, G and B channels to produce a false colour.

Take for example the most distant galaxy discovered by JWST, Glass-z13 the suffix indicating a redshift z = 13.

Despite the fact it has a “red colour” there is a problem if we associate this colour with a wavelength range.
The maximum wavelength the human eye can detect is around 700 nm which is in the red wavelength range of 620 – 750 nm.
If we apply the 1/(1+z) factor to the limit the human eye can detect, (1/14) x 700 = 50 nm.
This means Glass-z13 in its local frame of reference is primarily emitting X-rays which is not only invisible to the human eye but is also unrealistic when it comes to the evolution of galaxies.

The problem is the human eye and the detector process photons differently.
The detector is a photon counter which provides a distribution or histogram of photon energies.
The 1/(1+z) factor is applied to wavelengths to “un-redshift”; the application to an image on the other hand is not applying the factor to a wavelength but to a number and therefore cannot be used even as a simulation for colour in a local frame of reference.

What's up for you today? What's interesting that you're looking at lately?

Ironically it’s about topics I very rarely respond to such as evolution and US politics, and am amazed at the array of narrow minded comments presented.

 

[Halbhh]

You won’t even get a rough simulation for colour as perceived by the human eye as light in the infrared range is mapped into the R, G and B channels to produce a false colour.

Take for example the most distant galaxy discovered by JWST, Glass-z13 the suffix indicating a redshift z = 13.

Despite the fact it has a “red colour” there is a problem if we associate this colour with a wavelength range.
The maximum wavelength the human eye can detect is around 700 nm which is in the red wavelength range of 620 – 750 nm.
If we apply the 1/(1+z) factor to the limit the human eye can detect, (1/14) x 700 = 50 nm.
This means Glass-z13 in its local frame of reference is primarily emitting X-rays which is not only invisible to the human eye but is also unrealistic when it comes to the evolution of galaxies.

The problem is the human eye and the detector process photons differently.
The detector is a photon counter which provides a distribution or histogram of photon energies.
The 1/(1+z) factor is applied to wavelengths to “un-redshift”; the application to an image on the other hand is not applying the factor to a wavelength but to a number and therefore cannot be used even as a simulation for colour in a local frame of reference.


Ironically it’s about topics I very rarely respond to such as evolution and US politics, and am amazed at the array of narrow minded comments presented.

One of the fun things I learned years ago (5? 10 years ago?) is that early star types in the Universe would be dominated by supergiant stars low in metals and typically vastly larger than current stars around us now here in our local galaxy -- that's why I used an example to you above of a wolf rayet star -- 136a1 -- as a representative that is getting there: sorta like those early stars in that its very massive and emits almost all of its radiation in a range we cannot see.

But, and this is what I said above, but perhaps unclearly, if we could (magically) be much closer but not too close, so that instead a large redshift, we had a much smaller redshift (but we'd still be vastly distant then...), it would be fun to simulate what such a star might look like redshifted a smaller amount so that its main spectrum of emission is in the human visual range.

I expect if you read much in astronomy this might not be new to you about the supergiant low metal early stars. It's old to me and I tend to sometimes forget to mention things that are old to me.


I was on the other hand learning a new thing of some interest just before coming here to CF, which maybe would be interesting to you (unless you already read about it), about how the particular color choices in some of the spectacular galaxy images released to the public were chosen, in order to emphasize certain features of the emitting materials in a way that is more informative.

By bringing up the intensity of some features and subduing others, etc, but I'll quote a bit more than that also:

-------
“We have filters on the instruments that collect certain wavelengths of light, which we then apply a color that is most closely what we think it will be on the [visible] spectrum,” said Alyssa Pagan, a science visuals developer at the Space Telescope Science Institute, in a phone call with Gizmodo.

"The chromatic ordering depends too on what elements are being imaged. When working with narrow-band wavelengths in optical light—oxygen, ionized hydrogen, and sulfur, Pagan suggests—the latter two both emit in red. So the hydrogen might get shifted to green visible light, in order to give the viewer more information.

“It’s a balance between the art and the science, because you want to showcase science and the features, and sometimes those two things don’t necessarily work together,” Pagan added.

"When telescope images are being assembled, image processors work with instrument scientists to decide which features of a given object should be highlighted in the image: its piping hot gas, perhaps, or a cool dusty tail.

Stephan’s quintet as seen by three MIRI filters.

"When Webb imaged Stephan’s Quintet, a visual grouping of five galaxies, the finished product was a 150-million-pixel image made up of 1,000 images taken by both MIRI and NIRCam. When just seen by MIRI, though, hot dust dominates the image. In the background of the MIRI images, distant galaxies glow in different colors; DePasquale said the team calls them “skittles.”

"DePasquale and Pagan helped create the Webb images as we would eventually see them, rich in color and cosmic meaning. In the case of the sweeping shot of the Carina Nebula’s cosmic cliffs, different filters captured the ionized blue gas and red dust. In initial passes at the nebula image, the gas obscured the dust’s structure, scientists asked the image processing team to “tone down the gas” a bit, Pagan said.
Are the Colors in Webb Telescope Images 'Fake'?

 

[sjastro]

One of the fun things I learned years ago (5? 10 years ago?) is that early star types in the Universe would be dominated by supergiant stars low in metals and typically vastly larger than current stars around us now here in our local galaxy -- that's why I used an example to you above of a wolf rayet star -- 136a1 -- as a representative that is getting there: sorta like those early stars in that its very massive and emits almost all of its radiation in a range we cannot see.

But, and this is what I said above, but perhaps unclearly, if we could (magically) be much closer but not too close, so that instead a large redshift, we had a much smaller redshift (but we'd still be vastly distant then...), it would be fun to simulate what such a star might look like redshifted a smaller amount so that its main spectrum of emission is in the human visual range.

I expect if you read much in astronomy this might not be new to you about the supergiant low metal early stars. It's old to me and I tend to sometimes forget to mention things that are old to me.

While Wolf Rayet stars are extremely hot and give off a large amounts of radiation in the UV range their blackbody spectrum extends into the visible range allowing rank amateurs like myself to take spectra using diffraction grating technology, a modest telescope and a CCD sensor.

Here is the spectrum I took of the brightest Wolf Rayet star in the sky Gamma Velorum in the visible range indicating the presence of carbon and hydrogen.

Here is an image I took of the Wolf Rayet star SH2-308 in the visible spectrum showing the blue star near the centre having blown off its surface layers.

One of the objectives of the JWST is to search for hypothetical Population III stars which have practically zero metallicity and are believed to be largely formed from the primeval hydrogen and helium from the Big Bang.
These stars are considerably hotter and more massive than 136a1 and can have masses up to 1000 solar masses; by comparison 136a1 is around 196 solar masses.

I was on the other hand learning a new thing of some interest just before coming here to CF, which maybe would be interesting to you (unless you already read about it), about how the particular color choices in some of the spectacular galaxy images released to the public were chosen, in order to emphasize certain features of the emitting materials in a way that is more informative.

By bringing up the intensity of some features and subduing others, etc, but I'll quote a bit more than that also:

-------
“We have filters on the instruments that collect certain wavelengths of light, which we then apply a color that is most closely what we think it will be on the [visible] spectrum,” said Alyssa Pagan, a science visuals developer at the Space Telescope Science Institute, in a phone call with Gizmodo.

"The chromatic ordering depends too on what elements are being imaged. When working with narrow-band wavelengths in optical light—oxygen, ionized hydrogen, and sulfur, Pagan suggests—the latter two both emit in red. So the hydrogen might get shifted to green visible light, in order to give the viewer more information.

“It’s a balance between the art and the science, because you want to showcase science and the features, and sometimes those two things don’t necessarily work together,” Pagan added.

"When telescope images are being assembled, image processors work with instrument scientists to decide which features of a given object should be highlighted in the image: its piping hot gas, perhaps, or a cool dusty tail.

Stephan’s quintet as seen by three MIRI filters.

"When Webb imaged Stephan’s Quintet, a visual grouping of five galaxies, the finished product was a 150-million-pixel image made up of 1,000 images taken by both MIRI and NIRCam. When just seen by MIRI, though, hot dust dominates the image. In the background of the MIRI images, distant galaxies glow in different colors; DePasquale said the team calls them “skittles.”

"DePasquale and Pagan helped create the Webb images as we would eventually see them, rich in color and cosmic meaning. In the case of the sweeping shot of the Carina Nebula’s cosmic cliffs, different filters captured the ionized blue gas and red dust. In initial passes at the nebula image, the gas obscured the dust’s structure, scientists asked the image processing team to “tone down the gas” a bit, Pagan said.
Are the Colors in Webb Telescope Images 'Fake'?

I have mentioned in previous posts astronomers take two types of images, images of scientific value and images for public consumption particularly aimed at politicians who want to see bang for the buck which comes via public funding.

Scientific images are usually bland and in monochrome and when colour is used to emphasize detail it is usually in false colour with no colour balance and unnatural colours such as magenta coloured stars.
The Hubble Palette is one such example.

 

[Nithavela]

Let's hope mankind goes extinct before it spreads there.

 

[Sheila Davis]

Scientists have discovered a beautiful ocean world that looks like it was ripped out of the Star Wars prequels. The exoplanet TOI-1452 b was discovered just 100 light-years from Earth. A new paper on the discovery says that the entire planet is covered by a thick layer of water and that it’s located far enough from its star to possibly support life.

If TOI-1452b is covered in liquid water, that means the surface temperature is in the sweet spot that might support life. How cool is that?

Scientists discovered a beautiful ocean world 100 light-years from Earth

The article has a link to the original paper. Which has more detail, but is quite technical.

TOI-1452 b: SPIRou and TESS Reveal a Super-Earth in a Temperate Orbit Transiting an M4 Dwarf - IOPscience

Earth was a water world too
Earth History - Global Ocean - Earth Used to Be a Water World

And there is plenty of water out there in space
Scientists have found more water in space than they ever knew possible

 

[Estrid]

Earth was a water world too
Earth History - Global Ocean - Earth Used to Be a Water World

And there is plenty of water out there in space
Scientists have found more water in space than they ever knew possible

"May have been"

 

[Halbhh]

These stars are considerably hotter and more massive than 136a1 and can have masses up to 1000 solar masses;

Now that would be exciting.

It would be exciting to even find a star with even anything over 400 solar masses.

It would about the greatest astronomical discovery after black holes or the moons of Jupiter.

Here's why -- (I realize I have to risk telling you basic things and hope you won't be offended, just like you tell me basic things I've known for decades or even learned as a undergraduate in physics -- we'll have to do that to each other I guess, since we cannot guess what each other already has learned):

Eddington luminosity - Wikipedia

I can think of ways around the Eddington Limit, like stellar collisions.

Here's another reason it would be really something to see such a more massive star -- we don't really know, and it's all speculative:

How massive were the first stars?
Short answer: Probably really big, but maybe not.
MASS OF THE FIRST STARS The first stars were probably tens to hundreds of times the mass of the Sun, but might have been a lot smaller than this. CREDIT: STScI Get the full mass infographic in Resource Gallery
Although astronomers are quite certain what the first stars were made of, they are less sure how massive they were.

Strangely, one constraint on the mass of metal-free stars comes from what we don’t see: Because we haven’t observed any metal-free stars, we are fairly certain that there could not have been many small ones. Small stars like the Sun last for billions of years. If small Population III stars were common, we should have detected some by now.

Extremely large stars, on the other hand, burn their fuel very quickly. A star 60 times the mass of the Sun lasts less than one million years. If all of the first generation of stars were extremely massive, none would still exist, and it would make sense that we have not seen any.
What Were the First Stars Like?

So, you see, it would be really something to find a star massing like 400 solar masses or higher -- it would be a huge deal.

Quite a discovery, if one is seen. (Such a necessarily young star would have to be formed recently by stellar collisions I'm thinking)

And very exciting in additional ways: how might such a star might behave (which we can only guess at currently, having seen none).

So, you'd have not only the amazement at finding any such, but then next another likely amazement (at least for me!) that would come next: how they might behave.

That would be interesting.

 

[Halbhh]

Here is an image I took of the Wolf Rayet star SH2-308 in the visible spectrum showing the blue star near the centre having blown off its surface layers.

Nice! What telescope are you using, and how long an exposure?

 

[sjastro]

Nice! What telescope are you using, and how long an exposure?

Exposure details;

13.5 hours exposure with luminance filter using an OIII narrowband pass filter.
1 hour exposure with red filter
1 hour exposure with green filter
1 hour exposure with blue filter.

All exposures @ -15⁰ C.

Telescope 0.25M BRC-250

​

Camera STXL-11002 CCD.

 

[Halbhh]

Exposure details;

13.5 hours exposure with luminance filter using an OIII narrowband pass filter.
1 hour exposure with red filter
1 hour exposure with green filter
1 hour exposure with blue filter.

All exposures @ -15⁰ C.

Telescope 0.25M BRC-250

​

Camera STXL-11002 CCD.

Wow, no wonder you have such a good image.

 

[sjastro]

Wow, no wonder you have such a good image.

Here is a fun science fact.

The OIII emission (redshifted in the diagram) which shows up in the image which gives the nebula its cyan colour is according to quantum mechanics a forbidden transition.
It means it has a very low probability of occurring as collisions between atoms cause de-excitation before the transition can occur.
The transition is not observed on Earth in the very best laboratory vacuums as the number density of atoms per unit volume is too high.
Only in space has the gas has become so rarified the transition can occur.

The OIII transition was also mistaken as evidence for the fictitious element Nebulium.