JWST's first spectrum of a TRAPPIST-1 planet
phys.org
phys.org
btw PBS Nova has an awesome episode on JWST, how hard it was to get built and how it almost didn't get built because massively over budget ($10 Billion!)
https://www.pbs.org/video/ultimate-space-telescope-gunryt/
This is kind of a "part 2" follow-up after it was launched and "first light"
Edit: just to add that I found the segment on the alignment process of the 18 mirrors an interesting puzzle. Once you've found all of the pieces, you still have to decide what mirror each part of image represents. I've aligned my telescope mirror's primary/secondary mirrors on terra firma, but you at least have a bit of a feel for how much you're adjusting. Doing that remotely from 1M miles away, just makes it that much cooler
I will never not be amazed that we can read the atmospheric spectra of exoplanets.
Think about how light passed through a prism splits from white light into its rainbow colored components. It's the exact same thing. All you need to do is see what's missing, and you can discern the elemental composition of the atmosphere[s] that said light passed through. And it all started with Newton playing with a prism, and thinking beyond 'my, what pretty colors.'
The really cool thing about this is that it also can tell you some things that defy 'common knowledge.' For instance the Moon actually has a persistent atmosphere, and it's made out of sodium! It's exceptionally thin, but it's there - and can be picked up by spectroscopy.
[1] - https://en.wikipedia.org/wiki/Astronomical_spectroscopy
what gets me isn't the lack of complexity, but the lack of light. holding a prism to capture the sun's light or a flash light or whatever is simple since there's so much of it. even in telescopes, stars are mere pixels.
I remember an interesting astrobotany paper hypothesizing that if plants were to evolve on a red dwarf planet, there would be selective pressure for them to be black rather than green (for maximum light absorption, as most light would be infrared).
Or, the rich people could live in the temperate zone while the poor people choose between burning and freezing. Brb, writing a dystopian sci-fi.
Make sure to give Proxima by Baxter a read.
From the wiki on Trappist 1 - https://en.m.wikipedia.org/wiki/TRAPPIST-1
I think the public interest in it might be driving it? 40 light years is also kinda near to us, which might make it more interesting than Sun like systems if these are 100+ light years for example, if we were to want to do something about a possible detection.
Edit0: We don't know much of what conditions drive the genesis of life or where it might survive, so I'm not entirely sure that looking at red dwarves are a waste of time in a search for life.
They are also doing fundamental work in clearing up the influence of the star on their measurements!
Of the 131 stars and sub-stellar objects within 20 light years of the Earth, 101 are red or brown dwarfs. JWST/NIRISS has limited resolution, it's not going to be shooting spectra of exoplanet atmospheres of systems 50,000 light years away. They're just measuring every exoplanet system.
If you look up on a dark night, you can see 5 to 10 thousand stars. For every star you see there are 8 red dwarves. Not one of them is visible to the naked eye.
No red dwarf has died of old age yet. They live trillions of years and the universe isn't old enough.
Proxima Centauri might not be part of the centauri system. It's orbit is so long (80,000 years) that we can't tell if it is orbiting Alpha and Beta or just drifting by.
Since they are flare stars (suddenly increase 10 - 50 percent in brightness), there were a few minutes in 2015 where if you knew where to look you could see it.
The book (and netflix show) the three body problem is about aliens from the centauri star system.
w/apologies to JRR Tolkein, who said the correct word is dwarves.
* this is all from memory, might want to verify it.
Heck, TRAPPIST-1 itself isn't eye-visible. It's only slightly bigger than Jupiter! But these systems are hugely overrepresented in exoplanet surveys-- since we've only been hunting for exoplanets for a decade or so via the transit method, most of them have been found orbiting red dwarfs: the host star is so dim that transits take a big chunk out of their light curve, and the planets huddled up close to the star orbit so quickly that you can get the required three transits in a mere ten years of observation time.
It's a safe bet that there are gas giants like Neptune out there, but by the transit method it would take four centuries to find them! We invented the "hot Jupiter" category after Kepler launched, without nothing that we won't ever find "normal" gas giants without interstellar probes or space telescopes 10 km across.
I also always get confused with red dwarfs and red giants, about time I educated myself:
Red dwarfs are main sequence (i.e. in the prime of their life) stars that are small, and reddish.
Red giants are old stars, and what will become of our Sun.
This chart helped: https://en.m.wikipedia.org/wiki/Stellar_evolution#/media/Fil...
Unless there's a jovian planet with life out there your best bet at measuring a regular sized planet is around a small stars. Dwarfs.
When we had our massive planet surveys measuring transits we found a shit ton of jovian's around stars and some earth sized planets around smaller stars.
Time to measure transit and relative size are king.
https://science.nasa.gov/missions/hubble/superflares-from-yo...
https://earthsky.org/space/red-dwarf-stars-superflares-red-d...
https://www.space.com/red-dwarfs-activity-bad-news-alien-lif...
https://interestingengineering.com/science/red-dwarfs-superf...
From the last one:
> The magnetic fields' arrangement and intensity are responsible for areas of intense activity on the solar surface. For our Sun, these areas appear darker and are called sunspots, which have been found to occur in areas where solar flares are released.
> Solar flares from red dwarfs previously measured can be 100-1,000 times more potent than those released by our Sun. In 2019, Proxima Centauri, a red dwarf, let out a flare 14,000 times brighter than its pre-flare brightness.
> Solar flares are sometimes followed by hot plasma sent out from the star called coronal mass ejections (CMEs). Its scorching temperatures can blow strip away the atmospheres of planets and even boil away liquid water from the planet's surface, reducing the likelihood of it hosting life.
(Tangent to the tangent - https://youtu.be/FF_e5eYgJ3Y is a neat video - Close Encounter with a CME (Coronal Mass Ejection) :: On Sept. 5, 2022, NASA's Parker Solar Probe was about to make its 13th close approach to the Sun when a coronal mass ejection (CME) -- a powerful explosion of magnetic fields and plasma -- erupted right in front of it. ... )
This problem also sounds like one that can be extrapolated into more systems as those planets are going to be close to the star by necessity…?
Frustrating that the resolving power of JWST is there even for those, but the star completely dominates the observations.
I wonder if they could perform analysis over time and apply statistical models to subtract solar output from the data, knowing the orbital periods etc. But that’s just me being a layman here.
They do that in the paper. That's the "secondary eclipse", where the planet goes behind the star and they subtract the difference.
https://iopscience.iop.org/article/10.3847/2041-8213/acf7c4 [open access]
So they aren't really picking out specific stars intially. Once they've identified a candidate exoplanet, then they'll often try to confirm it using more direct/targetted observations.
See also: SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars)
Would be cool to have a dashboard of some sort that provided “probability this HN user will respond when called out for speaking from their behind”.