Kepler-36: a pair of planets with neighboring orbits and dissimilar densities.
In the solar system, the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern is not universal and that planets' orbits can change substantially after their formation. Here, we report another violation of the orbit-composition pattern: two planets orbiting the same star with orbital distances differing by only 10% and densities differing by a factor of 8. One planet is likely a rocky "super-Earth," whereas the other is more akin to Neptune. These planets are 20 times more closely spaced and have a larger density contrast than any adjacent pair of planets in the solar system.
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. jacarter@cfa.harvard.edu
Joshua A
JA
Carter
Eric
E
Agol
William J
WJ
Chaplin
Sarbani
S
Basu
Timothy R
TR
Bedding
Lars A
LA
Buchhave
Jørgen
J
Christensen-Dalsgaard
Katherine M
KM
Deck
Yvonne
Y
Elsworth
Daniel C
DC
Fabrycky
Eric B
EB
Ford
Jonathan J
JJ
Fortney
Steven J
SJ
Hale
Rasmus
R
Handberg
Saskia
S
Hekker
Matthew J
MJ
Holman
Daniel
D
Huber
Christopher
C
Karoff
Steven D
SD
Kawaler
Hans
H
Kjeldsen
Jack J
JJ
Lissauer
Eric D
ED
Lopez
Mikkel N
MN
Lund
Mia
M
Lundkvist
Travis S
TS
Metcalfe
Andrea
A
Miglio
Leslie A
LA
Rogers
Dennis
D
Stello
William J
WJ
Borucki
Steve
S
Bryson
Jessie L
JL
Christiansen
William D
WD
Cochran
John C
JC
Geary
Ronald L
RL
Gilliland
Michael R
MR
Haas
Jennifer
J
Hall
Andrew W
AW
Howard
Jon M
JM
Jenkins
Todd
T
Klaus
David G
DG
Koch
David W
DW
Latham
Phillip J
PJ
MacQueen
Dimitar
D
Sasselov
Jason H
JH
Steffen
Joseph D
JD
Twicken
Joshua N
JN
Winn