Atmospheric Retrieval of Exoplanets

How do we measure what exoplanet atmospheres are made of? As we move closer to observations of Earth-like atmospheres, exoplanet researcher Ryan MacDonald (Cambridge, UK) explains how astronomers retrieve the atmospheric properties of exoplanets.

-----Further information and links-----

*Recent reviews of exoplanet atmosphere research:

*An excellent textbook on exoplanet atmosphere theory:

*The first exoplanet atmosphere retrieval paper (Madhusudhan & Seager, 2009):

*'The presence of methane in the atmosphere of an extrasolar planet' (Swain et al. 2008):

*'HD 209458b in New Light' (Ryan's MNRAS paper):
[Contains an overview of exoplanet atmospheric retrieval for transmission spectra]

-Online version:

-Open access pdf (pre-typset author's manuscript):

*The James Webb Space Telescope (JWST):

*Hubble Space Telescope Wide Field Camera 3 (WFC3):

The schematic diagrams, cross section plots, and transmission spectra illustrations were produced by Ryan MacDonald, making use of the POSEIDON radiative transfer and retrieval algorithm.

[martiancolonist]

You asked for it, so here is an overview of the area my PhD research is focused around!

As far as I am aware, this is the first time a video has been made for the public that covers atmospheric retrieval, so I'll be really interested to hear your feedback.

Any questions about exoplanet atmospheres, life, the Universe, or everything? Feel free to fire away!
A selection of the most insightful comments will be featured (and you'll get a shoutout) at the end of my next video (currently targetted for July 9th).

- Ryan

[toolkit]

This was the most comprehensive explanation that I have seen to date. I wish more people would be able to explain this to the masses as we would be able to have more excitement for space. Exploration, even if it is just theoretical at this point.
Good job. Glad I found this channel.

[warpspeed]

Thanks Ryan for explaining some intriging aspects of exoplanet research and your role in helping to extract information from observations of exoplanets and finding new ways to explain observations. Your two-dimensional examples are clear to me and has helped me to understand the process of cleverly combining a range of factors (of which each factor can be considered as a "dimension") in order to remain with only one possible explanation (that is "one" as far as our knowledge and insight reaches).

[HerrAnGr]

Thank you. This is a great explanation.

At 12:08 you show which part of the spectrum is covered by the Hubble WFC3. At the end you speak about the James Webb telekop. Do you have infos, which part of the spectrum this will cover? Just to get a rough estimate, how much more infos we will get. The Webb is bigger. So it is catching more light. So this will also increase the time resolution, which is interesting at start/end of the transit.

How many molecule types are included today in the models? With a better resulution, it should also be possible to identify more complicated molecules. (e.g. Chlorophylle, Amino acid, ...) Once you have a 1st estimate of the temperature using models with maybe 20 simple molecules, you could again generate millions of models with more molecules, but now staying in the temperature range, that you estimated in the 1st step...

The example was, where we see the transit exactly from the center of the star. Is it possible to estimate, which part of the disc is crossed? (Maybe not on which pole side.)

[vbfswbs]

Your entusaism makes me very exited about exoplanet! Great video!

[lextalionis]

How wonderful. Making it easy to understand complex science is not simple. Thank you.

[sakshigupta]

That was really a wonderful explanation. I could clearly understand the physics behind the retrieval of atmosphere but could you also explain the techniques as in what codes and packages are used and a little explanation on how to implement those?

[desertdenizen]

Thank you for that excellent presentation! I might not be around to see how your research bears up under scrutiny but I am
heartened by the detail of analysis so far. It is wonderful to see a great mind at work. Do you think that your expertise will
increase your chances for Mars selection?

[Rajit_]

I am currently working with Exoplanetary Atmospheric Retrievals. This video helped me a lot. But I think you should update the video with JWST information.

[GirtonOramsay]

Sweet Ryan! I praise the astronomers working to achieve the detailed observations for these findings of exoplanet atmospheres that I wouldn't want to do. I'm looking to get into lab investigations of these discoveries with JWST and TESS for my future graduate school work (hopefully)!

[Mummele]

How are your calculation results distored by consecutive assumptions?

What measurement precision do we require in these spectra do distinguish between two molecules with different absorption behaviour?

[davidrobine]

I have to say, as a non-expert, your PhD seems assured! Great job Ryan! You're avery good teacher!

[Aizenvsanyonedontmix]

Excellent explanation. I was thinking throughout the video whether you'd be excited about the JWST! Glad to know that you are.

[agni-banerjee]

Thank you for such a clear presentation. Just what I was looking for.

[peterquant]

Very interesting, though I think I lost it near the end. Will revisit this video!

[seifraslan]

how will we know if there is a moon(s) around an exoplanet, is there a way ?

[tonmoydeka]

Oh wow its you. Didn't know you had a channel. I am currently learning about POSEIDON. I went through the tutorial that are in the website .

I want to know why molecular absorption lines are seen in higher wavelengths and not in shorter one.

[ExtremeEpicYoutub]

Why did you choose to become part of Mars One instead of creating your own Mars mission?

[slydesplaylists]

The exo mars program is completely awful but then yes, they are there hopes of catching up, the hunan race in my opinion if following such technology is very wrong in it's assuption most things, the expanding universe for instance and . of course currently observing the legends and past knowledge that were rediscoving better res. Also well the webb will change everything definantly. Not much though it's the same similar equipment. . We really should balance proton fuel and learn sub atomic capacity to control what is what we think we see and how our localised systematic formation here has us to believe . It has us near the first of our neighbours . Hopefully the U.S team will be successful in the first permanant sciece station. Which yeas the final crew will be probably the most important explorers ever in the history of our species . Way out huh.what you think? Cardman or Watkins like and other pairings, actually of the females also the nuclear engineer candidate. Well anyway theres the guys too like systems specialist or as recently though not a warning off the planet like the necessity for a Naval or USAF sharing of the need to take over and thrust by manual, hmmmm very Neil sure but then given the failure of the ESA lander essential . Someday the calculous and formulaes will be in one package to apply any technique in feeling or seeing our inate connection with planetary bodies . Ryan Mcdonald interesting .