TY - JOUR
T1 - Formation, tidal evolution, and habitability of the kepler-186 system
AU - Bolmont, Emeline
AU - Raymond, Sean N.
AU - Von Paris, Philip
AU - Selsis, Franck
AU - Hersant, Franck
AU - Quintana, Elisa V.
AU - Barclay, Thomas
PY - 2014/9/20
Y1 - 2014/9/20
N2 - The Kepler-186 system consists of five planets orbiting an early M dwarf. The planets have physical radii of 1.0-1.50 R ⊕and orbital periods of 4-130 days. The 1.1 R ⊕Kepler-186f with a period of 130 days is of particular interest. Its insolation of roughly 0.32 S ⊕places it within the surface liquid water habitable zone (HZ). We present a multifaceted study of the Kepler-186 system, using two sets of parameters which are consistent with the data and also self-consistent. First, we show that the distribution of planet masses can be roughly reproduced if the planets were accreted from a high surface density disk presumably sculpted by an earlier phase of migration. However, our simulations predict the existence of one to two undetected planets between planets e and f. Next, we present a dynamical analysis of the system including the effect of tides. The timescale for tidal evolution is short enough that the four inner planets must have small obliquities and near-synchronous rotation rates. The tidal evolution of Kepler-186f is slow enough that its current spin state depends on a combination of its initial spin state, its dissipation rate, and the stellar age. Finally, we study the habitability of Kepler-186f with a one-dimensional climate model. The planet's surface temperature can be raised above 273 K with 0.5-5 bars of CO2, depending on the amount of N2present. Kepler-186f represents a case study of an Earth-sized planet in the cooler regions of the HZ of a cool star.
AB - The Kepler-186 system consists of five planets orbiting an early M dwarf. The planets have physical radii of 1.0-1.50 R ⊕and orbital periods of 4-130 days. The 1.1 R ⊕Kepler-186f with a period of 130 days is of particular interest. Its insolation of roughly 0.32 S ⊕places it within the surface liquid water habitable zone (HZ). We present a multifaceted study of the Kepler-186 system, using two sets of parameters which are consistent with the data and also self-consistent. First, we show that the distribution of planet masses can be roughly reproduced if the planets were accreted from a high surface density disk presumably sculpted by an earlier phase of migration. However, our simulations predict the existence of one to two undetected planets between planets e and f. Next, we present a dynamical analysis of the system including the effect of tides. The timescale for tidal evolution is short enough that the four inner planets must have small obliquities and near-synchronous rotation rates. The tidal evolution of Kepler-186f is slow enough that its current spin state depends on a combination of its initial spin state, its dissipation rate, and the stellar age. Finally, we study the habitability of Kepler-186f with a one-dimensional climate model. The planet's surface temperature can be raised above 273 K with 0.5-5 bars of CO2, depending on the amount of N2present. Kepler-186f represents a case study of an Earth-sized planet in the cooler regions of the HZ of a cool star.
KW - methods: numerical
KW - planets and satellites: atmospheres
KW - planets and satellites: dynamical evolution and stability
KW - planets and satellites: formation
KW - stars: individual (Kepler-186 KIC 8120608)
UR - http://www.scopus.com/inward/record.url?scp=84906962157&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/793/1/3
DO - 10.1088/0004-637X/793/1/3
M3 - Article
AN - SCOPUS:84906962157
SN - 0004-637X
VL - 793
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 3
ER -