Luis
Welbanks
[email protected]
@luis_wel
luiswelbanks.com 1
Add essing he Challenges in
Unde s anding he Na u e o
Exoplane A mosphe es om hei
Spec a
51 Pegasi b Fellow → Assis an P o esso
Wha is ou place in he Uni e se?
Is Ea h special?
How unique is ou own Sola Sys em?
A e we alone?
C edi : NASA's Ea h Obse a o y
1. The Impo ance o Exoplane A mosphe es
2Towa ds new on ie s
Wha is ou place in he Uni e se?
Is Ea h special?
How unique is ou own Sola Sys em?
A e we alone?
C edi : NASA's Ea h Obse a o y
1. The Impo ance o Exoplane A mosphe es
Decadal o Plane a y Science and As obiology
Decadal o As onomy and As ophysics
Wha do ou plane a y sys ems e eal abou
exoplane a y sys ems?
Wha can exoplane a y sys ems each us abou he
sola sys em?
Wha o he po en ially habi able en i onmen s exis ?
Wha a e he p ope ies o indi idual plane s, and
which p ocesses lead o plane a y di e si y?
How can signs o habi able li e be iden i ied and
in e p e ed in he con ex o hei plane a y
en i onmen s?
The coming decades will se humani y down a pa h o
de e mine i we a e alone.
3
La ge Popula ion wi h La ge Di e si y
O e 5000
1. The Impo ance o Exoplane A mosphe es
4Towa ds new on ie s
La ge Popula ion wi h La ge Di e si y
O e 5000
1. The Impo ance o Exoplane A mosphe es
5
La ge Popula ion wi h La ge Di e si y
O e 5000
Ho
Jupi e s
Rocky
Plane s
La a
Wo lds
Ocean
Wo lds &
Ice Gian s
1. The Impo ance o Exoplane A mosphe es
6
Wide O bi
Gian s
Supe
Ea hs
La ge Popula ion wi h La ge Di e si y
Wha a e exoplane a mosphe es made o ?
Wha do composi ions ell us abou plane o ma ion?
Wha is he di e si y o plane a y clima es?
Wha makes ou Sola Sys em unique?
C edi : ESA/Hubble, N. Ba mann
1. The Impo ance o Exoplane A mosphe es
7
La ge Popula ion wi h La ge Di e si y
Wha a e exoplane a mosphe es made o ?
Wha do composi ions ell us abou plane o ma ion?
Wha is he di e si y o plane a y clima es?
Wha makes ou Sola Sys em unique?
C edi : ESA/Hubble, N. Ba mann
1. The Impo ance o Exoplane A mosphe es
8
The a mosphe e is he mos obse able
po ion o an ex a-sola body, he e o e
he in o ma ion we lea n abou he
p ocesses and his o y o ha objec will
come om i s a mosphe e.
Condie 2022
How should a mosphe ic me allici y change wi h plane a y mass?
2. The Legacy o HST
9
Le e aging he Popula ion o Unde s and
Plane Fo ma ion
Sola Composi ion
The HST Spec a Family Po ai
Madhusudhan 2019
2. The Legacy o HST
16 ≳50 ansmission spec a (Zhang 2020)
Wa e
e e ywhe e
Welbanks, e al. 2019b
2. The Legacy o HST
17
Wa e
e e ywhe e
~ 5849 plane s disco e ed (NASA Exoplane
A chi e)
≳50 ansmission spec a (Zhang 2020)
~ 12 di e en chemical species ha e been
iden i ied in ~ 30 di e en plane s
2. The Legacy o HST
18 Welbanks, e al. 2019b
Tes ing Hypo hesis on he P imo dial
Fo ma ion Pa hways o Exoplane s.
•Hypo hesis: Me allici y o a plane a y a mosphe e should inc ease wi h dec easing mass (co e-
acc e ion model o plane o ma ion)
•E idence: A end ha appea s wi hin he sola sys em Jo ian plane popula ion.
19
K eidbe g e al. 2014
See also, Madhusudhan 2014, Pinhas 2017, Chachan 2019
2. The Legacy o HST
19
WASP43b 2 Jupi e masses
1500 K
Tes ing Hypo hesis on he P imo dial
Fo ma ion Pa hways o Exoplane s.
•Hypo hesis: Me allici y o a plane a y a mosphe e should inc ease wi h dec easing mass (co e-
acc e ion model o plane o ma ion)
•E idence: A end ha appea s wi hin he sola sys em Jo ian plane popula ion.
20
K eidbe g e al. 2014
See also, Madhusudhan 2014, Pinhas 2017, Chachan 2019
2. The Legacy o HST
20
WASP43b 2 Jupi e masses
1500 K
Tes ing Hypo hesis on he P imo dial
Fo ma ion Pa hways o Exoplane s.
•Hypo hesis: Me allici y o a plane a y a mosphe e should inc ease wi h dec easing mass (co e-
acc e ion model o plane o ma ion)
•E idence: A end ha appea s wi hin he sola sys em Jo ian plane popula ion.
21
K eidbe g e al. 2014
See also, Madhusudhan 2014, Pinhas 2017, Chachan 2019
2. The Legacy o HST
21
WASP43b 2 Jupi e masses
1500 K
Remo e Sensing o Exoplane s 101
•To es ou heo ies we need cons ain s on
he chemical composi ion,
e ical/ho izon al empe a u e s uc u e,
ae osol p ope ies
•We use Bayesian pa ame e es ima ion
in ol ing a la ge ensemble o models (i.e.,
unning adia i e ans e housands o
millions o imes) o explo e he pa ame e
space ha can explain a se o obse a ions.
Welbanks 2021
22
2. The Legacy o HST
Plane Mass (M⊕)
Plane Mass (MJ)
23 Welbanks e al. 2019b
Compa ing Exoplane s composi ions o Sola Sys em
Sola Sys em
2. The Legacy o HST
Sola Composi ion
A eya e al. 2016
Elemen al en ichmen
Plane Mass (M⊕)
Plane Mass (MJ)
Compa ing Exoplane s composi ions o Sola Sys em
Welbanks e al. 2019b
Sola Sys em
24
2. The Legacy o HST
Sola Composi ion
A eya e al. 2016, Li e al. 2020
Juno
Elemen al en ichmen
Plane Mass (M⊕)
Plane Mass (MJ)
Exoplane s
25
Compa ing Exoplane s composi ions o Sola Sys em
Welbanks e al. 2019b
Sola Sys em
2. The Legacy o HST
Sola Composi ion
A eya e al. 2016, Li e al. 2020
Elemen al en ichmen
Plane Mass (M⊕)
Plane Mass (MJ)
JWST does p o ide be e da a
Madhusudhan 2023
Ye ou models a e impe ec , and ou in e ences model d i en
Mo an e al 2023
3. The JWST Re olu ion
32
GJ486b
JWST does p o ide be e da a
Madhusudhan e al 2023
Ye ou models a e impe ec , and ou in e ences model d i en
3. The JWST Re olu ion
33
K218b
This 6-sigma de ec ion o cheese could
happen i you y o explain he
composi ion o he moon wi h a cheese
model and a sponge model
34
3. The JWST Re olu ion
This 6-sigma de ec ion o cheese could
happen i you y o explain he
composi ion o he moon wi h a cheese
model and a sponge model
35
How do we assess wha in he da a d i e ou
in e ences?
How do we ensu e ou models a e ‘good’?
How do we p e en alling in o a ap o compa ing wo
‘bad’ models?
3. The JWST Re olu ion
Building Physical Insigh s om a Da a D i en
Pe spec i e
H− opaci y was de ec ed in HAT-P-41b a 2.9𝜎, bu his de ec ion de ies ou physical in ui ion.
Using Bayesian Lea e-One-Ou C oss-Valida ion we show ha his in e ence was d i en by a
single da a poin .
36 Welbanks e al. 2023
3. The JWST Re olu ion
Building Physical Insigh s om a Da a D i en
Pe spec i e
H− opaci y was de ec ed in HAT-P-41b a 2.9𝜎, bu his de ec ion de ies ou physical in ui ion.
Using Bayesian Lea e-One-Ou C oss-Valida ion we show ha his in e ence was d i en by a
single da a poin .
37 Welbanks e al. 2023
This new me ic has gi en us con ex o ou
in e ences
3. The JWST Re olu ion
3. The JWST Re olu ion
38
Add essing Key Ques ions in he e a o
JWST
To answe hese ques ions we need
cons ain s on:
•Chemical composi ion
•Ve ical/Ho izon al empe a u e s uc u e
•P esence o clouds/hazes
How should a mosphe ic
me allici y change wi h
plane a y mass?
Wha is he ange o
a mosphe ic elemen al
a ios?
Wha physical p ocesses
go e n plane a y clima e?
4. Ea ly Science wi h JWST
Ea ly Release Science wi h JWST
39
Welbanks e al. in p ep
WASP39b
Radius 1.3 Jupi e Radii
Mass 0.3 Jupi e Masses (~Sa u n mass)
Tempe a u e ~1200 K
Ea ly Release Science wi h JWST
Welbanks e al. in p ep
4. Ea ly Science wi h JWST
40
WASP39b
Radius 1.3 Jupi e Radii
Mass 0.3 Jupi e Masses (~Sa u n mass)
Tempe a u e ~1200 K
Welbanks e al. in p ep o Na u e
Dalba e al. 2015
Sa u n om Cassini
Ea ly Release Science wi h JWST
4. Ea ly Science wi h JWST
41
De ec ing All Majo
Elemen Rese oi s
in an Exoplane
Welbanks e al. 2024, Na u e
48
WASP107b
Radius 0.9 Jupi e Radii
Mass 0.09 Jupi e Masses
Tempe a u e ~700 K
4. Ea ly Science wi h JWST
We see many ca bon species
⇒ Can’ be ha low o a C/O
⇒ SO2 implies no in equilib ium
⇒ Likely disequilib ium!
4. Ea ly Science wi h JWST
49
In e nal hea ing in la es he low-densi y plane WASP-107b
Le e aging a mosphe ic cons ain s o ind a
unique solu ion o he plane ’s composi ion and
in e io p ope ies
High in e nal empe a u e
Low in e nal empe a u e
Equilib ium expec a ion
Welbanks e al. 2024, Na u e
4. Ea ly Science wi h JWST
50
In e nal hea ing in la es he low-densi y plane WASP-107b
Le e aging a mosphe ic cons ain s o ind a
unique solu ion o he plane ’s composi ion and
in e io p ope ies
High in e nal empe a u e
Low in e nal empe a u e
Equilib ium expec a ion
Welbanks e al. 2024, Na u e
WASP-107 b is a “popco n plane ”
Eccen ici y d i en idal hea ing is a c i ical p ocess go e ning a mosphe ic
chemis y and in e io s uc u e in e ences o a majo i y o he cool supe -Ea h- o-
Sa u n mass exoplane popula ion
51
This is Jus he Beginning o 20 Yea s wi h JWST
4. Ea ly Science wi h JWST
JWST
Decembe 2021
ELTs
~2030
HWO
>2040
We can now ob ain a holis ic iew o
exoplane a mosphe es answe ing no only
wha a e exoplane a mosphe es made o ,
bu which da a d i e ou in e ences and how
eliable a e hese in e ences.
The Fu u e is B igh
New Knowledge
Be e
Da a
Be e
Model
5. The Fu u e is B igh
52
New F on ie s o As ochemis y in
Exoplane A mosphe es
5. The Fu u e is B igh
53
Signal alida ion
Is he signal obus ? Is he ‘bump’ eally he e?
Signal a ibu ion
A e he spec al ea u es co ec ly a ibu ed o he app op ia e
gases?
In e p e a ion
How eliable a e he de i ed plane a y p ope ies?
New F on ie s o As ochemis y in
Exoplane A mosphe es
5. The Fu u e is B igh
54
Inspi ed and adap ed om he wo ks o Ma eo B ogi.
see e.g., Smi h e al. 2024, Kanumalla e al. 2024, Gandhi
e al. 2024, B ogi e al. 2023
How do we ush he bounda ies o ou
knowledge o gas gian s and ocky
exoplane s wi h HRS and LRS?
Chemical iden i ica ion wi h HRS
e.g., P ino h 2025
6. Concluding Though s
55
The sea ch o chemical species wi h JWST has esul ed in de ec ions o
CH4, SO2, CO2, CO, SO2, H2O, NH3
In he e a o JWST de ec ing chemical species means mo e han a sigma model p e e ence
Signal alida ion
Signal a ibu ion
In e p e a ion
We can connec a mosphe ic cons ain s o he in e io s uc u e o he plane and he plane
dynamics.
Ques ions:
How is ou disco e y space limi ed by ou model assump ions?
Wha does i mean o ‘de ec ’ a gas?
Can we eally cons ain plane o ma ion? e olu ion?
A e we eady o ind ____ as we don’ know i ?
