Comment by autocorr | Hacker News Reader

Comment by autocorr | Hacker News Reader

One of the most exciting things about this discovery is that because Barnard's star is so close, the planet should have a maximum angular separation of 0.22 arcseconds. Directly imaging the planet in reflected light from the star [1] will be no problem for next generation telescopes in terms of resolution and sensitivity -- telescopes like the 30 meter class facilities being built now or a hypothetical ~10 meter space telescope called "LUVOIR". Current cutting edge instruments like the Gemini Planet Imager (GPI) can already get to about 0.2 arcsec resolution, but it operates in the infrared and can only detect down to about a Jupiter-mass depending on how hot the planet is. The really exciting thing about imaging a planet in reflected light is that you can study the composition of the atmosphere in much greater detail than current methods [2]. This is likely the first system that astronomer's will target when they seek to make direct observations of a rocky planet's atmosphere outside of our Solar System.

[1] Ss opposed to the thermal infrared, which works best for young planets which have substantial residual heat from their formation. [2] Such as when an exoplanet transits in front of it's host star, the atmosphere will absorb some light. However it appears this technique is only sensitive to the very thin upper parts of the atmosphere, and we don't learn much about the rest.

How many years is such a discovery away?

The Extremely Large Telescope in Chile, which fits the "30 meter class" description, is scheduled to be operational in 2024.

Luvoir is expected to launch in the mid-2030s. It is one of at least two exoplanet detection-and-characterization missions that is under study by NASA.

> Luvoir is expected to launch in the mid-2030s

For others who are not familiar with the NASA studies, "expected" is probably too strong a word and "proposed" is probably more accurate. LUVOIR is one of four flagship mission concepts which NASA has provided with seed money. They will all be evaluated during the coming 2020 Decadal Survey of Astronomy and Astrophysics. The recommendations from that survey will then be used as guidance for NASA. So if the Decadal Survey ranks LUVOIR as a top priority (the missions are all so large that it is unlikely more than one would be funded), and if they meet their proposed timeline, then it would launch in the mid-2030s. So it's not yet a given that LUVOIR will happen (another mission could be more highly ranked), and the timeline should be taken with a grain of salt.

This is 100% accurate.

In fact, given the timeline, I’d be surprised if either Luvoir or HabEx, as currently envisioned, actually flies. There is a lot of technical innovation that will happen between now and then, even if the Decadal recommends one or the other.

(I work on yield modeling for the study. I make plots and animations of observations, and the times on the plot labels have disconcertingly-far-off times like 2036.)

I imagine that an image of a planet around another star would have similar global impact as the Earth-rise picture from the Apollo missions did / does - sort of uniting people from different nations by giving them a visceral reaction from a totally new pov.

Is such an "image" why we are discussing here?

It all depends on jwst. If that flops, or even if it only goes as planned, without the spectacular over-performance expected of nasa stuff these days, future large space telescopes will be shelved for a generation At least the optical ones.

My worry is that jwst will be too short-lived. It cannot become the fixture for decades that hubble has been.

Personally I'm most looking forward to the James Webb Telescope [1]. It's expected to be launched as soon as 2007!

https://en.wikipedia.org/wiki/James_Webb_Space_Telescope

2007 is NASA/ESA MOU, the planned launch is now 2021.

Whoosh!

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