!"

Methane present in an extrasolar planet atmosphere

#$%&"'(")*$+,-."/$01$2"3$4+451-."6"/+78$,,$"9+,:11+;("

*Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive,

Pasadena, California 91109-8099 USA. † Department of Physics and Astronomy,

University College London, Gower Street, London WC1E 6BT, UK. ‡ Exoplanet and

Stellar Astrophysics Laboratory, Code 667, NASA’s Goddard Space Flight Centre,

Greenbelt, Maryland 20771-0001, USA.

‘These authors contributed equally to this work’

!"#$%&#$'()*$'$+,(-+($.")#/+$,/*0(/,1"')2$*$'(/*$($.)$%,$3(,"(',*"+4#0(

-+5#&$+%$(,2$(/,1"')2$*-%(*/3-/,-"+(6/#/+%$7(,*/%$(30+/1-%/#(/+3(%2$1-%/#()*"%$''$'7(

/+3(-+3-%/,$(,2$()*$'$+%$("5(3-'$8&-#-6*-&1($55$%,'9((:-+%$(1"#$%&#$'(2/;$(,2$()",$+,-/#(

,"(*$;$/#(,2$($.")#/+$,(/,1"')2$*-%(%"+3-,-"+'(/+3(%2$1-',*07('$/*%2-+4(5"*(,2$1(-'(/(

2-42()*-"*-,09((<2$(*",/,-"+/#=;-6*/,-"+/#(,*/+'-,-"+(6/+3'("5(>/,$*7(%/*6"+(1"+".-3$7(

/+3(1$,2/+$(/*$(/+,-%-)/,$3(,"(6$(,2$()*-1/*0('"&*%$'("5(+"+=%"+,-+&&1(")/%-,0(-+(

2",=?";-/+()#/+$,'@7A7B9((:-+%$(,2$'$(6/+3'(";$*#/)(-+(>/;$#$+4,27(/+3(,2$(

%"**$')"+3-+4('-4+/,&*$'(5*"1(,2$1(/*$(>$/C7(3$%-'-;$(-3$+,-5-%/,-"+(*$8&-*$'(

)*$%-'-"+(-+5*/*$3(')$%,*"'%")09((D$*$(>$(*$)"*,("+(/(+$/*=-+5*/*$3(,*/+'1-''-"+(

')$%,*&1("5(,2$()#/+$,(DE(@FGHBB6('2">-+4(,2$()*$'$+%$("5(1$,2/+$9((I33-,-"+/##07(/(

*$'"#;$3(>/,$*=;/)"&*(6/+3(/,(@9G(!1(%"+5-*1'(,2$(*$%$+,(%#/-1J("5(>/,$*(-+(,2-'(

"6K$%,9((L+(,2$*1"%2$1-%/#(4*"&+3'7(%/*6"+=1"+".-3$(-'($.)$%,$3(,"(6$(/6&+3/+,(-+(

,2$(&))$*(/,1"')2$*$("5(2",=?";-/+($.")#/+$,'M(,2&'(,2$(3$,$%,-"+("5(1$,2/+$(*/,2$*(

,2/+(%/*6"+=1"+".-3$(-+('&%2(/(2",()#/+$,N7O(%"&#3('-4+/#(,2$()*$'$+%$("5(/(2"*-P"+,/#(

<"

%2$1-%/#(4*/3-$+,(/>/0(5*"1(,2$()$*1/+$+,(3/0'-3$7("*(-,(1/0(-1)#0(/+(-##=

&+3$*',""3()2","%2$1-%/#(1$%2/+-'1'(,2/,(#$/3'(,"(/+($+2/+%$1$+,("5(1$,2/+$9"

97"=$1:."27>:?0>$%"4+@,$10%:4"5$8:",71"A::,"%:47>8:="+,"15:":2+44+7,"4B:?1%$"7C"571D

E78+$,":F7B>$,:14G.H.I.!J

(""9%$,42+44+7,"4B:?1%74?7BK"=0%+,@"15:"B%+2$%K":?>+B4:"L*5:,"15:"

B>$,:1"7??0>14"$"B7%1+7,"7C"15:"41:>>$%"=+4&."$,="$"C%$?1+7,"7C">+@51"C%72"15:"41$%"+4"4::,"$C1:%"

1%$8:%4$>"15%70@5"15:"$1274B5:%:"$%70,="15:"B>$,:1M4">+2AN"5$4"15:"$=8$,1$@:"7C"A:+,@"

+,4:,4+1+8:"17"1:2B:%$10%:"41%0?10%:"+,"15:":F7B>$,:1O4"$1274B5:%:!!(""P0:"17"15:"B%:4:,?:"7C"

41%7,@"27>:?0>$%"$A47%B1+7,"A$,=4.",:$%D+,C%$%:="4B:?1%74?7BK"C%72"!Q<(R"!2"+4"*:>>"40+1:="

C7%"=:1:?1+7,"7C"15:"4+@,$10%:4"7C"S<T."UT."$,="USV(""W7%"$"571DE78+$,"$1274B5:%:"+,"

B0%:>K"15:%27?5:2+?$>":X0+>+A%+02."15:"=72+,$,1"?$%A7,DA:$%+,@"27>:?0>:"+4":FB:?1:="17"

A:"UT"$1"5+@5:%"1:2B:%$10%:4"L9:X"Y"!<JJ"ZN"$,="USV""$1">7*:%"1:2B:%$10%:4"L9:X"["HJJ"ZN(""

T,"15:"=$K4+=:4"7C"15:"457%1DB:%+7=."1+=$>>KD>7?&:="571DE0B+1:%4."15:">7?$>"?$%A7,"?5:2+41%K"

4570>="A:"=72+,$1:="AK"UT\"=+4:X0+>+A%+02":CC:?14"2$K"%:40>1"+,"UT"$4"15:"=72+,$,1"

?$%A7,D?$%%K+,@"27>:?0>:.":8:,"7,"15:"1:%2+,$17%"$,=",+@514+=:4"7C"40?5"B>$,:14](""T0%"

=:1:?1+7,"7C"15:"7,4:1"7C"15:"USV"A$,=5:$="$1"<(<"!2"+4"15:"C+%41"?>:$%"4B:?1%$>"4+@,$10%:"7C"$"

?$%A7,DA$4:="27>:?0>:"+,"$,":F7B>$,:1"$1274B5:%:("

^:"7A4:%8:="15:"1%$,4+1+,@":F7B>$,:1"SP"!HIG__A"*+15"15:"S0AA>:")B$?:"9:>:4?7B:"

04+,@"15:"`aU#T)"L`aUD_N"?$2:%$"7,"#$K"<R."<JJG."78:%"C+8:"?7,1+@0704"4B$?:?%$C1"

7%A+14(""P0%+,@"15:4:"7A4:%8$1+7,4."`aU#T)"*$4"?7,C+@0%:="17"7A1$+,"$"4B:?1%7B57172:1%+?"

1+2:"4:%+:4"A:1*::,"!(V"Q"<(R"!2(""b4"15:"B$%:,1"41$%."SP"!HIG__."+4":F1%:2:>K"A%+@51"LZ"c"

R(R<N."*:"=:C7?04:="15:"`aU#T)"?$2:%$"17"+,?%:$4:"15:"4$10%$1+7,"1+2:"7C"+,=+8+=0$>"

=:1:?17%"B+F:>4(""95+4"B%78+=:="$==+1+7,$>"A:,:C+14"C7%"B%:?+4+7,"B57172:1%K!<"AK"$>>7*+,@"

472:"4B$1+$>"$8:%$@+,@"78:%"+,1%$DB+F:>"$,="B+F:>D17DB+F:>"X0$,102":CC+?+:,?K"8$%+$1+7,4"

15$1"?70>="?70B>:"17"%$B+="1:>:4?7B:"B7+,1+,@":%%7%4"$,="4>7*"B7+,1+,@"=%+C14"17"B%7=0?:"

_"

4B0%+704"+,1:,4+1K"C>0?10$1+7,4"+,"15:"2:$40%:="1+2:"4:%+:4(""95:"=:C7?04"=:1:%2+,:4"15:"

4B:?1%$>"%:47>01+7,"$>>7*+,@"04"17":F1%$?1"!H"+,=:B:,=:,1"*$8:>:,@15"?5$,,:>4"*+15"

40CC+?+:,1"4+@,$>D17D,7+4:("95:%:"$%:"@$B4"+,"15:"2:$40%:="1+2:"4:%+:4"A:?$04:"15:"41$%"SP"

!HIG__"+4",71"+,"15:"d?7,1+,0704"8+:*+,@"e7,:f"7C"15:"4B$?:?%$C1."$,=."A:?$04:"7C"

4?5:=0>+,@"?7,41%$+,14."15:"+,D:?>+B4:"=$1$"$%:",71"4K22:1%+?"$A701"15:":B7?5"7C"+,C:%+7%"

?7,g0,?1+7,("

P0%+,@"B%+2$%K":?>+B4:"15:"$BB$%:,1"A%+@51,:44"7C"15:"41$%"=:?%:$4:="AK"h"<(V"i"LW+@("

!N(""S7*:8:%."$4"15:"27=0>$1+7,"$2B>+10=:"=0:"17",72+,$>"$270,14"7C"*$1:%"8$B70%!_"+4"

B%:=+?1:="17"A:"42$>>"L["J(!iN."5+@5D=K,$2+?D%$,@:"Lh!JVN"4B:?1%$"$%:"%:X0+%:="17"=:1:?1"

$,="?5$%$?1:%+4:"$,K"27>:?0>$%"C:$10%:4(""b>1570@5"15:"S0AA>:")B$?:"9:>:4?7B:"$87+=4"15:"

>+2+1$1+7,4"+2B74:="AK"15:"j$%15M4"$1274B5:%:."4B:?1%7B57172:1%K"*+15"`aU#T)"7%"715:%"

7,DA7$%="+,41%02:,14!<.!V"+4"40Ag:?1"17"4K41:2$1+?":%%7%4"15$1"2041"A:"?7%%:?1:="A:?$04:"15:"

:%%7%4"$%:"4+2+>$%"+,"4+e:"17"15:":FB:?1:="27>:?0>$%"4+@,$10%:4(""a,"70%"=$1$."15:"C+%41"7%A+1"

5$="41%7,@"4K41:2$1+?"7CC4:14"L=0:"17"4B$?:?%$C1"4:11>+,@N"$,="*$4":F?>0=:="C%72"70%"

$,$>K4+4("

a,"7%=:%"17"$%%+8:"$1"15:"1%$,42+44+7,"4B:?1%02"+1"+4"+2B7%1$,1"17":41$A>+45"$"B%7B:%"

A$4:>+,:"C7%"15:"%:2$+,+,@"701D7CD:?>+B4:"=$1$("95:"4K41:2$1+?4"+,"15:"%$*">+@51?0%8:4"$%:"

=72+,$1:="AK"1*7"1KB:4."?7%%:>$1+7,4"+,"1+2:"$,="+,"*$8:>:,@15("a,"7%=:%"17"%:278:"

1:2B7%$>"?7%%:>$1+7,4."*:"$4402:="15$1"15:"7A4:%8:="C>0F"+,":$?5"*$8:>:,@15"?5$,,:>"C7%"

15:"701D7CD:?>+B4:"7%A+14"?70>="A:"27=:>>:="AK"B:%10%A$1+7,4"15$1"*:%:">+,:$%"+,"C+8:"41$1:"

8$%+$A>:4."$,="AK"$"1:%2"15$1"*$4"0B"17"B$%$A7>+?"+,"4B$?:?%$C1"7%A+1$>"B5$4:(""95:"41$1:"

8$%+$A>:4"?$B10%:"15:"7B1+?$>"41$1:"7C"15:"?$2:%$"$,="$%:"15:"?:,1%7+=4"7C"?5$,,:>4."$"8$%+$A>:"

=:C7?04"=0:"17"kkA%:$15+,@MM"7C"15:"1:>:4?7B:"C7?04."%71$1+7,"7C"15:"4B:?1%02"*+15"%:4B:?1"17"

15:"=:1:?17%."$,="1:2B:%$10%:(""b"%:@%:44+7,"17"15:"7A4:%8:=">+@51?0%8:4"B%78+=:="15:"

V"

?7:CC+?+:,14"7C"15:"27=:>(""^5:,"=:?7%%:>$1:="A$4:="7,"15:"27=:>."15:"1+2:"4:%+:4"457*:="

,7"C0%15:%"1:2B7%$>"?7%%:>$1+7,4(")72:"%:2$+,+,@":F?:44",7+4:"*$4"41%7,@>K"?7%%:>$1:="+,"

*$8:>:,@15\"$,":41+2$17%"C7%"15+4",7+4:"*$4"?7,41%0?1:="$4"$"*:+@51:="$8:%$@:"7C"$>>"

?5$,,:>"1+2:"4:%+:4"=$1$"L?7>>$B4:="+,"15:"*$8:>:,@15"$F+4N"$,="*$4"15:,"40A1%$?1:="C%72"

+,=+8+=0$>"?5$,,:>4(""95:"%:40>1+,@"?5$,,:>"1+2:"4:%+:4"$%:",:$%"=:1:?1+7,",7+4:">+2+1:=("95:"

%7A041,:44"7C"15:"C+14"*$4"8:%+C+:="AK"%:278+,@"4:?1+7,4"7C"15:"=$1$"C%72"15:"C+1"$,="

:,40%+,@"15$1"15:"?72A+,:="%:4+=0$>4"%:2$+,"*:>>"A:5$8:=("

95:"+,D:?>+B4:"1+2:"4:%+:4"1:2B7%$>":CC:?14"*:%:"=:?7%%:>$1:="AK"$BB>K+,@"15:"27=:>"

?7:CC+?+:,14"=:1:%2+,:="C%72"15:"701D7CD:?>+B4:"=$1$"17"41$1:"8$%+$A>:4"$,="15:"4B$?:?%$C1"

7%A+1$>"B5$4:"$1":8:%K"1+2:D41:B"=0%+,@"15$1"7%A+1(""bC1:%"$??70,1+,@"C7%"15:"?5%72$1+?"

:CC:?14"+,1%7=0?:="+,"15:":?>+B4:">+@51"?0%8:"AK">+2A"=$%&:,+,@."$"*$8:>:,@15"=:?7%%:>$1+7,"

*$4"B:%C7%2:="04+,@"15:"4$2:"2:157="$4"*$4"04:="C7%"15:"701D7CD:?>+B4:"7%A+14(""95:"1%$,4+1"

1+2:"4:%+:4.",7*"$>47"?7%%:?1:="C7%"+,41%02:,1"4K41:2$1+?4."*$4"$8:%$@:="17"?7,41%0?1"$"

1%$,42+44+7,"4B:?1%02(""95+4"4B:?1%02"+,?>0=:4"$41%7B5K4+?$>"A+$4:4"15$1"5$8:"*:$&"

?5%72$1+?"=:B:,=:,?:."=0:"17"$8:%$@+,@"78:%">+2AD=$%&:,:=">+@51"?0%8:4"$,="$>47"=0:"17"

15:"B%:4:,?:"7C"?77>"41$%4B714"7,"15:"=+4&"7C"15:"41$%(""95:":CC:?1"7C">+2A"=$%&:,+,@."1570@5"

,71"$4"=%$2$1+?"$4"+,"7B1+?$>"=$1$."+4"?>:$%>K"4::,"$4"?0%8$10%:"+,"15:":?>+B4:">+@51"?0%8:4"

LW+@("!N(""^:"?7D$==:="15:"4B:?1%$>"?5$,,:>4"17"?7,41%0?1"4K,15:1+?">+@51"?0%8:4"2$1?5+,@"15:"

S"$,="Z"$41%7,72+?$>"A$,=4."C7%"*5+?5"15:%:"$%:"B0A>+45:=",7,D>+,:$%.">+2A"=$%&:,+,@"

>$*4!R(""^:"15:,"?7,41%0?1:="$"?72B01:%"27=:>"7C"$">+2AD=$%&:,:="41$%"$,="4+20>$1:="15:"

271+7,"7C"15:"B>$,:1"$?%744"15:"41:>>$%"=+4&"04+,@"15:"4K41:2M4"Z:B>:%+$,"B$%$2:1:%4!V.!]"17"

@:,:%$1:"27=:>">+@51"?0%8:4(""b"41::B:41"=:4?:,1"4?5:2:"*$4"04:="17"C+1"@:,:%$1:="?0%8:4"17"

15:"2:$40%:="=$1$"AK">:$8+,@"15:"B>$,:1":CC:?1+8:"%$=+04"L+,"15$1"A$,=N"$,=":B7?5"7C"1%$,4+1"

$4"C%::"B$%$2:1:%4(""95:"A:41"C+1">+@51"?0%8:4"+,":$?5"A$,="*:%:"04:="17":41+2$1:"15:">+2AD

=$%&:,+,@"A+$4:4\"15:"2:$,"?7%%:?1+7,"+4"<l!JDV."$,="15:"?7>70%"?7%%:?1+7,"+4"!l!J

DV"$?%744"

R"

15:"A$,=(""95:"B%:4:,?:"7C"41$%4B714"7,"SP"!HIG__"5$4"A::,"+,C:%%:=!]"C%72"2:$40%:2:,14"

7C">7,@D1:%2."701D7CD:?>+B4:"8$%+$A+>+1K."$,="C%72"15:"41%0?10%:"7C"1%$,4+1">+@51"?0%8:4"+,"15:"

7B1+?$>!V(""m,7??0>1:="41$%4B714"+,1%7=0?:"$"B74+1+8:"?5%72$1+?"A+$4"+,"15:"+,C:%%:="

$A47%B1+7,"=:B15."4+,?:"15:K"$%:"?77>:%"15$,"15:"41:>>$%"=+4&\"+,"15:"+,C%$%:=."15:"?5%72$1+?+1K"

7C"15+4":CC:?1"+4"42$>>"$,="27,717,+?."$,="1504"5$4">+11>:":CC:?1"7,"15:"45$B:"7C"15:"7A4:%8:="

27=0>$1+7,(""^:"=:%+8:="$"?7%%:?1+7,"*+15"$"41$%"4B71"?78:%$@:"7C"V"i"04+,@"27=:>"

4B:?1%$!G"$,="$4402+,@"15$1"15:"41$%4B714"*:%:"7,"$8:%$@:"!JJJ"Z"?77>:%"15$,"15:"RJJJ"Z"

41:>>$%"B57174B5:%:(""b"27%:"=:1$+>:="=:4?%+B1+7,"7C""15:"=$1$"%:=0?1+7,"2:157="+4"?7,1$+,:="

+,"15:")0BB>:2:,1$%K"a,C7%2$1+7,"*5+?5"+4">+,&:="17"15:"7,>+,:"8:%4+7,"7C"15:"B$B:%"$1"

***(,$10%:(?72n,$10%:("""

^:"457*"15:"?7%%:?1:="4B:?1%02"$4"%:>$1+8:"$A47%B1+7,"=:B15"+,"W+@0%:"<(""95:"

4+@,$10%:"7C"15:"S<T"$A47%B1+7,"A$,="?:,1%:="$%70,="!(I"!2"+4"+22:=+$1:>K"7A8+704(""95:"

41::B"+,?%:$4:"+,"$A47%B1+7,"$1"15:"457%1"*$8:>:,@15":=@:"+4"$>47"2741"B%7A$A>K"=0:"17"$,"

$=g$?:,1"*$1:%"A$,="?:,1%:="457%1*$%="7C"!(R"!2(""9504."15:",:*"4B:?1%02"$>>7*4"$,"

0,$2A+@0704"+=:,1+C+?$1+7,"7C"*$1:%"8$B70%"+,"15:"$1274B5:%:"7C"SP"!HIG__A."?7,C+%2+,@"

+14":$%>+:%"+,C:%:,?:"C%72"A%7$=A$,="B57172:1%KV("")+,?:"$"41::B"?5$,@:"+,"$A47%B1+7,"

7??0%4"$1"<(<"!2."15:"7A4:%8$1+7,4"=:?+4+8:>K"457*"15$1"2:15$,:"+4"B%:4:,1"+,"$==+1+7,"17"

*$1:%(""97":FB>7%:"15:"$A0,=$,?:"7C"S<T"$,="USV"$,="B744+A>:"?7,1%+A01+7,4"7C"UT"$,="

`S_."4+20>$1:="1%$,42+44+7,"4B:?1%$"*:%:"@:,:%$1:="04+,@"$"%:?:,1"8:%4+7,"7C"$"B>$,:1$%K"

4B:?1%$>"27=:>!_(""95:"27=:>"?78:%4"$"%$,@:"7C"B%:440%:"C%72"∼!J"17"∼!JD!J"A$%"$,="+,?>0=:4"

1%$,4+1+7,4!H"C7%"S<DS<"L15:"2741"?7227,"27>:?0>$%"4B:?+:4N(""95:"1:2B:%$10%:"$,="=:,4+1K"

$1":$?5"$1274B5:%+?">:8:>"$%:"=:1:%2+,:="AK"15:"oD9"B%7C+>:."$,="15:"$A47%B1+7,"?7,1%+A01+7,"

17":$?5"27>:?0>:"+4"?72B01:="A$4:="7,"+14"2+F+,@"%$1+7("95:"S<T"$A47%B1+7,"?7:CC+?+:,14"

+,?7%B7%$1:"$",:*."5+@5D$??0%$?K">+41!I."$,="15:"UT"$A47%B1+7,"?7:CC+?+:,14"*:%:":41+2$1:="

*+15"15:"Sa9j#o"=$1$"A$4:"Lp()("'7152$,":1"$>(."dSa9j#o."15:"S+@5D9:2B:%$10%:"

]"

#7>:?0>$%")B:?1%74?7B+?"P$1$A$4:f."B%+8$1:"?7220,+?$1+7,N(""95:"USV"$A47%B1+7,"

?7:CC+?+:,14"*:%:":8$>0$1:="04+,@"$"?72A+,$1+7,"7C">+,:">+414<J.<!(""W7%"$>>"15:"27>:?0>:4."15:"

7B$?+1+:4"$%:"?$>?0>$1:="C7%"15:"4:>:?1:="4B:?1%$>"A$,="$1"15:"=+CC:%:,1"1:2B:%$10%:4"7C"15:"

$1274B5:%+?">$K:%4"LC%72"RJJ"Z"17"<JJJ"ZN"$,="+,"472:"?$4:4!H.<!"+,1:%B7>$1:="C7%"

+,1:%2:=+$1:"8$>0:4"7C"15:"$8$+>$A>:"1:2B:%$10%:4(""^:"04:="15:"d:8:,+,@"1:%2+,$17%f"

B%:440%:D1:2B:%$10%:"B%7C+>:<<\"4+@,+C+?$,1>K"=+CC:%:,1"1:2B:%$10%:"B%7C+>:4"B%7=0?:"%:40>14"

15$1"=7",71"2$1?5"15:"7A4:%8:="*$1:%"8$B70%"$A47%B1+7,"C:$10%:4(""95:"15:7%:1+?$>"4B:?1%$"

*:%:"A+,,:="17"15:"4$2:"4B:?1%$>"%:47>01+7,"$4"15:"2:$40%:2:,14."$,="15:"%:40>14"7C"

=+CC:%:,1"?72B74+1+7,4"*:%:"?72B$%:="*+15"15:"7A4:%8$1+7,4"04+,@"15:"%:=0?:=""<"8$>0:(""

U72A+,$1+7,4"7C"S<T"$,="UT."$4"*:>>"$4"S<T"$,="`S_"C$+>:="17"2$1?5"15:"7A4:%8:="

4B:?1%02(""95:"27=:>"A:41"C+11+,@"15:"7A4:%8$1+7,4"5$4"$"2+F+,@"%$1+7"7C"≅Rl!JDV"C7%"S<T."

$,="<Rl!JDR"C7%"USV"L4::"W+@("<N\"15:"$==+1+7,"7C"`S_"*+15"$"2+F+,@"%$1+7"7C"!l!JDR"

+2B%78:4"15:"C+1"4>+@51>K(""95:"$@%::2:,1"A:1*::,"70%"S<T"2+F+,@"%$1+7"8$>0:"$,="B%:8+704"

%:40>14V"+4"4+@,+C+?$,1"A:?$04:"$"*+=:"%$,@:"7C"*$8:>:,@154."?78:%+,@"15%::"2$g7%"S<T"

$A47%B1+7,"A$,=4."?$,"A:"27=:>>:="4:>CD?7,4+41:,1>K\"15+4"+2B>+:4"15:":41+2$1:="S<T"2+F+,@"

%$1+7"+4"%7A041(""95:"B%:440%:"$1"*5+?5"15:"$1274B5:%:"A:?72:4"7B1+?$>>K"15+?&"%$,@:4"C%72"

$"C:*"2+>>+A$%4."*5:,"15:"$A47%B1+7,"+4"41%7,@."17"hJ(<"A$%4."*5:,"15:"$A47%B1+7,"+4"*:$&:%"

L:(@("h"!(G"!2N(""^:"5$8:"27=:>>:="15:":CC:?1"7C"$:%747>4"$,="=:1:%2+,:="15$1"70%"4B:?1%02"

+4"5$e:DC%::."$4"15:+%"?7,1%+A01+7,"*70>="=:B%:44"15:"4B:?1%$>"4+@,$10%:"7C"A715"S<T"$,="USV"

%:>$1+8:"17"15:"2:$40%:="$A47%B1+7,"=:B15(""aC"$:%747>4"$%:"B%:4:,1."$4"+4"40@@:41:="AK"%:?:,1"

2:$40%:2:,14!V."15:K"2041"A:"+,"15:"C7%2"7C"42$>>"B$%1+?>:4"$,="15:+%"$CC:?14"?7,C+,:="17"

*$8:>:,@154"457%1:%"15$,"!(R"!2<_("

^5+>:"*:"?$,"0,$2A+@0704>K"=:1:%2+,:"USV"+4"B%:4:,1."15:"USV"$A0,=$,?:":41+2$1:"

+4"=:B:,=:,1"7,"0,?:%1$+,1+:4"*+15"15:"5+@5D1:2B:%$10%:"1%$,4+1+7,4(""b==+1+7,$>>K."15:"

B%:4:,?:"7C"USV"2$4&4"15:":CC:?1"7C"UT"+,"15:"$A47%B1+7,"4B:?1%02(""^5+>:"15:"A:41"C+1"+4"

G"

7A1$+,:="04+,@"7,>K"S<T"$,="USV."UT"?$,"A:"+,?>0=:="0B"17"15:"$A0,=$,?:"7C"S<T"*+15"$"

27=:41"+,?%:$4:"+,""<(""9504."*:"?$,,71"41%7,@>K"?7,41%$+,"$A0,=$,?:"7C"UT"7%"15:"

:>:2:,1$>"UnT"%$1+7(""95:"%:>$1+8:>K"5+@5"?7,?:,1%$1+7,"7C"USV"?70>="A:"=0:"+,"B$%1"17"

B5717?5:2+41%K(""o5717>K4+4"7C"UT"$,="USV"+4"B%7A$A>K",71"4+@,+C+?$,1"+,"15:"0BB:%"

$1274B5:%:"Lo"["!JDV"A$%N"7C"SP"!HIG__A"A:?$04:"7C"15:"41%:,@15"7C"UDT"$,="UDS"A7,=4"

$,="15:"=:C+?+1"7C"0>1%$8+7>:1"C>0F"C%72"+14"?77>"B$%:,1"41$%"L4B:?1%$>"1KB:"Z<3N(""S7*:8:%."

15:"B5717>K4+4"7C"15:"*:$&:%"A7,=4"7C"40>B50%.",+1%7@:,."$,="7FK@:,DA:$%+,@"?72B70,=4."

$,="15:"$??72B$,K+,@"$8$+>$A+>+1K"7C"C$41D%:$?1+,@"C%::"%$=+?$>4"?70>="5$8:"$"4+@,+C+?$,1"

+2B$?1"7,"15:"%:>$1+8:"$A0,=$,?:4<V"7C"USV"8:%404"UT(""

"

':?:+8:="!_"):B1:2A:%("

!(! ):$@:%.")("6")$44:>78."P("P("95:7%:1+?$>"1%$,42+44+7,"4B:?1%$"=0%+,@":F1%$47>$%"

@+$,1"B>$,:1"1%$,4+14("Astrophys. J NBH7"pI!]QpI<!"L<JJJN(""

<(! q0%%7*4."b("b"15:7%:1+?$>">77&"$1"15:"=+%:?1"=:1:?1+7,"7C"@+$,1"B>$,:14"7014+=:"15:"

47>$%"4K41:2("Nature"JBB7"<]!Q!<]H"L<JJRN("

_(! W7%1,:K."E("E(."U77:%."U(")(.")57*2$,."b("o(."#$%>:K."#(")(."6"W%::=2$,("'(")("95:"

+,C>0:,?:"7C"$1274B5:%+?"=K,$2+?4"7,"15:"+,C%$%:="4B:?1%$"$,=">+@51"?0%8:4"7C"571"

E0B+1:%4("Astrophys. J."ONA7"GV]QGRG"L<JJ]N("

V(! 9+,:11+."/("^$1:%"8$B70%"+,"15:"$1274B5:%:"7C"$"1%$,4+1+,@":F1%$47>$%"B>$,:1("Nature"

JJF7"!]IQ!G!"L<JJGN("

R(! Z,0147,."S("b(."et al."b"2$B"7C"15:"=$KD,+@51"?7,1%$41"7C"15:":F1%$47>$%"B>$,:1"SP"

!HIG__A("Nature."JJH7"!H_QH]"L<JJGN("

H"

](! U77B:%."U(")("6")57*2$,."o("PK,$2+?4"$,="=+4:X0+>+A%+02"?$%A7,"?5:2+41%K"+,"571"

E0B+1:%"$1274B5:%:4"*+15"$BB>+?$1+7,"17"SP"<JIVRHA("Astrophys. J."OJG7"!JVHQ!J]_"

L<JJ]N("

G(! '+?5$%=47,."p("E(."P:2+,@."P(."S7%,+,@."Z(."):$@:%.")(."6"S$%%+,@17,."E("b"4B:?1%02"

7C"$,":F1%$47>$%"B>$,:1("Nature"JJN7"HI<QHIR"L<JJGN("

H(! /%+>>2$+%."U("E("et al."b")B+1e:%"4B:?1%02"7C"15:":F1%$47>$%"B>$,:1"SP"!HIG__A("

Astrophys. J."OFN7"p!!RQp!!H"L<JJGN("

I(! )*$+,."#"'(."q70*2$,."E(."b&:47,."'("p(."p$*>:%.")."6"q:+?52$,."U("b("95:"2+=D

+,C%$%:="4B:?1%02"7C"15:"1%$,4+1+,@":F7B>$,:1"SP"<JIVRHA("Astrophys. J."OHJ."VH<Q

VIH"L<JJHN("

!J(!W7%1,:K."E("E("6"#$%>:K."#(")("b,$>K4+4"7C")B+1e:%")B:?1%$"7C"a%%$=+$1:="o>$,:14r"

j8+=:,?:"C7%"^$1:%"3$B7%s"Astrophys. J."OOO7"pVRQpVH"L<JJGN("

!!(!S0AA$%=."^("q(."W7%1,:K."E("E(."p0,+,:."E("a(."q0%%7*4."b(.")0=$%4&K."P(."6"o+,17."o("

95:7%K"7C"jF1%$47>$%"/+$,1"o>$,:1"9%$,4+14."bBE."NOQ."V!_QV!I"L<JJ!N("

!<(!/+>>+>$,=."'("p("6"b%%+A$4.")(."S+@5"4+@,$>D17D,7+4:"=+CC:%:,1+$>"`aU#T)"

4B:?1%7B57172:1%K("Inst. Sci. Rep. NICMOS."QQ@."!Q!V"L<JJ_N("

!_(!9+,:11+."/("et al."a,C%$%:="1%$,42+44+7,"4B:?1%$"C7%":F1%$47>$%"@+$,1"B>$,:14("

Astrophys. J."ONJ7"pIIQp!J<"L<JJGN("

!V(!o7,1."W("et al("S0AA>:")B$?:"9:>:4?7B:"1+2:D4:%+:4"B57172:1%K"7C"15:"B>$,:1$%K"

1%$,4+1"7C"SP!HIG__r",7"277,.",7"%+,@4."41$%4B714("Astron. Astrophys. J."JHO."!_VGQ

!_RR"L<JJGN("

I"

!R(!U>$%:1."b("b",:*",7,D>+,:$%">+2AD=$%&:,+,@">$*"C7%"p9j"41:>>$%"$1274B5:%:"27=:>4("

U$>?0>$1+7,4"C7%"DR(J"#"">7@t#nSu"#"v!."<JJJ#9:CC#RJJJJ"Z"$1"4:8:%$>"40%C$?:"

@%$8+1+:4("Astron. & Astrophys."BOB7"!JH!Q!!IJ"L<JJJN("

!](!^+,,."E("`("et al."95:"1%$,4+1">+@51"?0%8:"B%7g:?1"3(")K41:2"B$%$2:1:%4"$,="41:>>$%"

%71$1+7,"B:%+7="7C"SP"!HIG__("Astronom. J."@BB7"!H<HQ!H_R"L<JJGN("

!G(!S$04?5+>=1."o("S(."b>>$%=."W(."6"q$%7,."j("95:"`:F1/:,"#7=:>"b1274B5:%:"/%+="C7%"

_JJJ"[9:CC"[!J.JJJ"Z("Astrophys. J."N@A7"_GGQ_HR"L!IIIN("

!H(!q7%K47*."b(."E7%@:,4:,."m("/(."6"W0."w(."S+@5"1:2B:%$10%:"L!JJJDGJJJZN"?7>>+4+7,"

+,=0?:="$A47%B1+7,"7C"S<"B$+%4"?72B01:="C%72"15:"C+%41"B%+,?+B>:4."*+15"$BB>+?$1+7,"

17"?77>"$,="=:,4:"41:>>$%"$1274B5:%:4."Journ. of Quant. Spec. and Rad. Trans.."OF."

<_!Q<RR"L<JJ!N("

!I(!q$%A:%"."'("E(."9:,,K47,."E(."S$%%+4."/("E("6"97>?5:,78."'("b"5+@5"$??0%$?K"

?72B01:="*$1:%">+,:">+41("Mon. Not. R. Astron. Soc."BOF7"!JHGQ!JIV"L<JJ]N("

<J(!'7152$,."p(")("et al."95:"Sa9'b`"<JJV"27>:?0>$%"4B:?1%74?7B+?"=$1$A$4:."Journ.

of Quant. Spec. and Rad. Trans."GO."!_IQ<JV"L<JJRN(""

<!(!`$44$%."'(."6"q:%,$15."o(."dS71"2:15$,:"4B:?1%$"C7%"$41%7B5K4+?$>"$BB>+?$1+7,4f."

Journ. of Quant. Spec. and Rad. Trans.."FA."<GIQ<I<"L<JJ_N("

<<(!q0%%7*4."b(.")0=$%4&K."P(."6"S0A:,K."a("95:7%K"C7%"15:"4:?7,=$%K":?>+B4:"C>0F:4."

4B:?1%$."$1274B5:%:4"$,=">+@51"?0%8:4"7C"1%$,4+1+,@":F1%$47>$%"@+$,1"B>$,:14("

Astrophys. J.."ONQ7"!!VJQ!!VI"L<JJ]N("

<_(!q%7*,."9("#(."9%$,42+44+7,")B:?1%$"$4"P+$@,741+?4"7C"jF1%$47>$%"/+$,1"o>$,:1"

b1274B5:%:4. Astrophys. J., NBB7(@QQO=@QAO(RAQQ@S9"

!J"

<V(!p+$,@"#(DU(."):$@:%.")(."o$%&+,47,."U("P(."p::."b("w(D9."6"w0,@."w(p("T,"15:"

+,4+@,+C+?$,?:"7C"B5717?5:2+?$>"5K=%7?$%A7,"$:%747>4"+,"15:"$1274B5:%:4"7C"?>74:D

+,":F1%$47>$%"@+$,1"B>$,:14("b41%7B5K4("E("OQN7"p]"Qp]V"L<JJVN("

"

I%C+">#$34$1$+,'"^:"15$,&"P%$&:"P:2+,@"C7%"?7,1%+A01+7,4"17"15:"7%+@+,$>"B%7B74$>"$,="C7%"40@@:41+7,4"

C7%"?>$%+CK+,@"15:"2$1:%+$>"B%:4:,1:="+,"15:"2$,04?%+B1(""^:"15$,&"9722K"^+&>+,=."`7%"o+%e&$>."$,="715:%"

2:2A:%4"7C"15:")B$?:"9:>:4?7B:")?+:,?:"a,41+101:"41$CC"C7%":F1:,4+8:"$44+41$,?:"+,"B>$,,+,@"15:"7A4:%8$1+7,4"

$,="C7%"B%78+=+,@"$=8+?:"$A701"*$K4"+,"*5+?5"15:"7A4:%8$1+7,4"?70>="A:"7B1+2+e:=(""^:"$>47"15$,&"Z,0="

E$5,&:"C7%"40@@:41+,@"15:">7,@D*$8:>:,@15"`aU#T)"@%+42."W%:=:%+?"o7,1"C7%"=+4?044+7,4"?7,?:%,+,@"15:"

1%:$12:,1"7C"15:"=$1$."#DU"p+$,@"C7%"=+4?044+7,4"7,"B5717>K4+4."E75$15$,"9:,,K47,"$,="q7A"q$%A:%"C7%"

40@@:41+7,4"7,"15:"2:15$,:"=$1$">+414(""/("9+,:11+"*$4"40BB7%1:="AK"15:"mZ")?+:,?:4"6"9:?5,7>7@K"W$?+>+1+:4"

U70,?+>"$,="15:"j0%7B:$,")B$?:"b@:,?K(""95:"%:4:$%?5"=:4?%+A:="+,"15+4"B$B:%"*$4"?$%%+:="701"$1"15:"E:1"

o%7B0>4+7,"p$A7%$17%K."U$>+C7%,+$"a,41+101:"7C"9:?5,7>7@K."0,=:%"$"?7,1%$?1"*+15"15:"`$1+7,$>"b:%7,$01+?4"$,="

)B$?:"b=2+,+41%$1+7,("

"

I&,2"*(T+5"*1/,-"+"':B%+,14"$,="B:%2+44+7,4"+,C7%2$1+7,"+4"$8$+>$A>:"$1"***(,$10%:(?72n%:B%+,14(""95:"

$0157%4"=:?>$%:",7"?72B:1+,@"+,1:%:414(""U7%%:4B7,=:,?:"$,="%:X0:414"C7%"2$1:%+$>4"4570>="A:"$==%:44:="17"#("

)*$+,"L:D2$+>r"#$%&('()*$+,xgB>(,$4$(@78N("

"

"#$%&!'(!!Calibrated measurements showing the primary eclipse event.!!)*+!

,+-./0+1!2$,+!.+0$+.!"$3!/3$2.!,$3/2+.!45!,41$5$+1!6/7$-3!1-8(9!:400+:2+1!540!

.8.2+,-2$:!+0040.9!45!54/0!40;$2.!45!2*+!</;;7+!=>-:+!)+7+.:4>+&!!)*+!>0$,-08!

+:7$>.+!4::/0.!1/0$3%!2*+!.+:431!40;$29!-31!2*+!:/0?-2/0+!45!2*+!+:7$>.+!7$%*2!:/0?+!

!!"

$.!1/+!24!7$,;!1-0@+3$3%!45!2*+!.2-0&!!)*+!2A4!2$,+!.+0$+.!.*4A3!-0+!:4B-11+1!

.>+:20-7!1-2-!->>04C$,-2+78!,-2:*$3%!2*+!<!-31!D!-.20434,$:-7!;-31.!"'&EF'&G!!,!

.*4A3!$3!;7/+!H!I&JFI&K!!,!.*4A3!$3!0+19!0+.>+:2$?+78(&!!)*+!%->.!$3!2*+!2$,+!

.+0$+.!-0+!;+:-/.+!<L!'GMNOO!$.!342!$3!2*+!:432$3/4/.!?$+A$3%!P43+!540!2*+!

</;;7+!=>-:+!)+7+.:4>+&!!#40!:7-0$289!2*+!0+1!7$%*2!:/0?+!*-.!;++3!455.+2&!

!

"#$%&!I(!!A comparison of observations with simulated water and methane

absorption.!!)*+!,+-./0+1!.>+:20/,!";7-:@!20$-3%7+.(9!-31!2A4!2*+40+2$:-7!.>+:20-!

45!2*+!>0+14,$3-3278!<I!-2,4.>*+0+9!.*4A$3%!2*+!+55+:2.!45!.,-77!-,4/32.!45!A-2+0!

";7/+(!-31!,+2*-3+!$3!:4,;$3-2$43!A$2*!A-2+0!"40-3%+(&!!)*+!,+-./0+1!.>+:20/,!

:432-$3.!.$%3$5$:-32!1$55+0+3:+.!-2!'&N!F!'&G!!,!-31!I&'Q!F!I&K!!,!504,!A*-2!$.!

+C>+:2+1!1/+!24!A-2+0!?->4/0!-743+&!!R+!$32+0>0+2!2*+.+!1+>-02/0+.!-.!-11$2$43-7!

-;.40>2$43!5+-2/0+.!1/+!24!2*+!>0+.+3:+!45!43+!40!,40+!,47+:/7+.!$3!-11$2$43!24!

A-2+0&!!R*+3!:43.$1+0$3%!4378!A-2+0!-31!,+2*-3+9!2*+!2*+40+2$:-7!.>+:20/,!;+.2!

5$22$3%!2*+!1-2-!A-.!1+2+0,$3+1!;8!;$33$3%!2*+!,41+7!".*4A3!-.!A*$2+!:04..+.(!24!

2*+!.>+:20-7!0+.47/2$43!45!2*+!4;.+0?-2$43.&!!L$55+0+32!,41+7!>0+1$:2$43.!;-.+1!43!

:*-3%$3%!-;/31-3:+.!-31!,47+:/7+.!A+0+!:4,>-0+1!24!2*+!4;.+0?-2$43.!/.$3%!2*+!

0+1/:+1!"IS!2*+!;+.2!5$22$3%!,41+7!*-.!-!A-2+0!-;/31-3:+!45!QT'JBK!-31!-!,+2*-3+!

-;/31-3:+!45!QT'JBQ&!!)*+!,41+7!.>+:20/,!:-3!;+!$,>04?+1!.7$%*278!A$2*!2*+!

-11$2$43!45!.,-77!"U'T'JBQ(!-,4/32.!45!+$2*+0!-,,43$-!40!:-0;43!,434C$1+!".*4A3!

$3!%0++3!-31!>/0>7+!:04..+.9!0+.>+:2$?+78(&!!)*+!+0040!;-0.!540!2*+!,+-./0+,+32.!

-0+!>7/.!-31!,$3/.!43+!.$%,-!A*+0+!2*+!+0040!$3:7/1+.!2*+!/3:+02-$328!$3!2*+!

:400+:2$43!45!.8.2+,-2$:!+55+:2.!".++!=/>>7+,+32-08!V3540,-2$43(&!!W42+!2*-2!

1+2+0,$3$3%!2*+!P+04!>4$32!540!2*+!.>+:20/,!1+>+31.!43!2*+!1$-,+2+0!-../,+1!540!

!<"

2*+!>7-3+2!-31!-../,>2$43.!$3!2*+!.2-0!.>42!:400+:2$43&!!)*/.9!2*+!.*->+!45!2*+!

.>+:20/,!$.!04;/.2S!2*+0+!$.!-3!/3:+02-$328!45!XIT'JBK!$3!2*+!-;.47/2+!7+?+7&!