South-polar features on Venus similar to those near the north pole.
Venus has no seasons, slow rotation and a very massive atmosphere, which is mainly carbon dioxide with clouds primarily of sulphuric acid droplets. Infrared observations by previous missions to Venus revealed a bright 'dipole' feature surrounded by a cold 'collar' at its north pole. The polar dipole is a 'double-eye' feature at the centre of a vast vortex that rotates around the pole, and is possibly associated with rapid downwelling. The polar cold collar is a wide, shallow river of cold air that circulates around the polar vortex. One outstanding question has been whether the global circulation was symmetric, such that a dipole feature existed at the south pole. Here we report observations of Venus' south-polar region, where we have seen clouds with morphology much like those around the north pole, but rotating somewhat faster than the northern dipole. The vortex may extend down to the lower cloud layers that lie at about 50 km height and perhaps deeper. The spectroscopic properties of the clouds around the south pole are compatible with a sulphuric acid composition.
INAF-IASF (Istituto di Astrofisica Spaziale e Fisica Cosmica), Rome, Italy. Giuseppe.piccioni@iasf-roma.inaf.it
G
G
Piccioni
P
P
Drossart
A
A
Sanchez-Lavega
R
R
Hueso
F W
FW
Taylor
C F
CF
Wilson
D
D
Grassi
L
L
Zasova
M
M
Moriconi
A
A
Adriani
S
S
Lebonnois
A
A
Coradini
B
B
Bézard
F
F
Angrilli
G
G
Arnold
K H
KH
Baines
G
G
Bellucci
J
J
Benkhoff
J P
JP
Bibring
A
A
Blanco
M I
MI
Blecka
R W
RW
Carlson
A
A
Di Lellis
T
T
Encrenaz
S
S
Erard
S
S
Fonti
V
V
Formisano
T
T
Fouchet
R
R
Garcia
R
R
Haus
J
J
Helbert
N I
NI
Ignatiev
P G J
PG
Irwin
Y
Y
Langevin
M A
MA
Lopez-Valverde
D
D
Luz
L
L
Marinangeli
V
V
Orofino
A V
AV
Rodin
M C
MC
Roos-Serote
B
B
Saggin
D M
DM
Stam
D
D
Titov
G
G
Visconti
M
M
Zambelli
Eleonora
E
Ammannito
Alessandra
A
Barbis
Rainer
R
Berlin
Carlo
C
Bettanini
Angelo
A
Boccaccini
Guillaume
G
Bonnello
Marc
M
Bouye
Fabrizio
F
Capaccioni
Alejandro Cardesin
AC
Moinelo
Francesco
F
Carraro
Giovanni
G
Cherubini
Massimo
M
Cosi
Michele
M
Dami
Maurizio
M
De Nino
Davide
D
Del Vento
Marco
M
Di Giampietro
Alessandro
A
Donati
Olivier
O
Dupuis
Sylvie
S
Espinasse
Anna
A
Fabbri
Agnes
A
Fave
Iacopo Ficai
IF
Veltroni
Gianrico
G
Filacchione
Katia
K
Garceran
Yamina
Y
Ghomchi
Maurizio
M
Giustini
Brigitte
B
Gondet
Yann
Y
Hello
Florence
F
Henry
Stefan
S
Hofer
Gerard
G
Huntzinger
Juergen
J
Kachlicki
René
R
Knoll
Kouach
K
Driss
Alessandro
A
Mazzoni
Riccardo
R
Melchiorri
Giuseppe
G
Mondello
Francesco
F
Monti
Christian
C
Neumann
Fabrizio
F
Nuccilli
Jerome
J
Parisot
Claudio
C
Pasqui
Stefano
S
Perferi
Gisbert
G
Peter
Alain
A
Piacentino
Carlo
C
Pompei
Jean-Michel
JM
Reess
Jean-Pierre
JP
Rivet
Antonio
A
Romano
Natalie
N
Russ
Massimo
M
Santoni
Adelmo
A
Scarpelli
Alain
A
Semery
Alain
A
Soufflot
Douchane
D
Stefanovitch
Enrico
E
Suetta
Fabio
F
Tarchi
Nazzareno
N
Tonetti
Federico
F
Tosi
Bernd
B
Ulmer