TY - JOUR
T1 - Evolutionary models for ultracool dwarfs
AU - Silva Fernandes, Catarina
AU - Van Grootel, Valérie
AU - J. A. J. Salmon, Sébastian
AU - Aringer, Bernhard
AU - J. Burgasser, Adam
AU - Scuflaire, Richard
AU - Brassard, Pierre
AU - Fontaine, Gilles
PY - 2019/7/10
Y1 - 2019/7/10
N2 - Ultracool dwarfs (UCDs) have emerged as key targets for searches of transiting exoplanets. Precise estimates of the host parameters (including mass, age, and radius) are fundamental to constraining the physical properties of orbiting exoplanets. We have extended our evolutionary code Code Liégeois d'Evolution Stellaire to the UCD regime. We include relevant equations of state (EOSs) for H, He, as well as C and O elements to cover the temperature-density regime of UCD interiors. For various metallicities, we couple the interior models to two sets of model atmospheres as surface boundary conditions. We show that including C and O in the EOS has a significant effect close to the H-burning limit mass. The typical systematic error associated with uncertainties in input physics in evolutionary models is ∼0.0005 Mo. We test model results against observations for objects whose parameters have been determined from independent techniques. We are able to reproduce dynamical mass measurements of LSPM J1314+1320AB within 1σ with the condition of varying the metallicity (determined from calibrations) up to 2.5σ. For GJ 65AB, a 2σ agreement is obtained between individual masses from differential astrometry and those from evolutionary models. We provide tables of UCD models for various masses and metallicities that can be used as reference when estimating parameters for ultracool objects.
AB - Ultracool dwarfs (UCDs) have emerged as key targets for searches of transiting exoplanets. Precise estimates of the host parameters (including mass, age, and radius) are fundamental to constraining the physical properties of orbiting exoplanets. We have extended our evolutionary code Code Liégeois d'Evolution Stellaire to the UCD regime. We include relevant equations of state (EOSs) for H, He, as well as C and O elements to cover the temperature-density regime of UCD interiors. For various metallicities, we couple the interior models to two sets of model atmospheres as surface boundary conditions. We show that including C and O in the EOS has a significant effect close to the H-burning limit mass. The typical systematic error associated with uncertainties in input physics in evolutionary models is ∼0.0005 Mo. We test model results against observations for objects whose parameters have been determined from independent techniques. We are able to reproduce dynamical mass measurements of LSPM J1314+1320AB within 1σ with the condition of varying the metallicity (determined from calibrations) up to 2.5σ. For GJ 65AB, a 2σ agreement is obtained between individual masses from differential astrometry and those from evolutionary models. We provide tables of UCD models for various masses and metallicities that can be used as reference when estimating parameters for ultracool objects.
U2 - 10.3847/1538-4357/ab2333
DO - 10.3847/1538-4357/ab2333
M3 - Journal article
SN - 0004-637X
VL - 879
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 94
ER -