[en] 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 M⊙. 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.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Silva Fernandes, Catarina ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Van Grootel, Valérie ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Salmon, Sébastien ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Aringer, Bernhard; Università di Padova > Dipartamento di Fisica e Astronomia Galileo Galilei
Burgasser, Adam J.; University of California, San Diego > Center for AStrophysics and Space Science
Scuflaire, Richard ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Brassard, Pierre; Université du Québec > Départment de Physique
Fontaine, Gilles; Université du Québec > Départment de Physique
Language :
English
Title :
Evolutionary models for ultracool dwarfs
Publication date :
10 July 2019
Journal title :
Astrophysical Journal
ISSN :
0004-637X
eISSN :
1538-4357
Publisher :
University of Chicago Press, United States - Illinois
Bazot, M., Christensen-Dalsgaard, J., Gizon, L., Benomar, O., (2016) MNRAS, 460, p. 1254
Boyajian, T.S., Von Braun, K., Van Belle, G., (2012) ApJ, 757 (2), p. 112
Brassard, P., Fontaine G.ed Chabrier G.and Schatzman, E., (1994) IAU Coll. 147: The Equation of State in Astrophysics, p. 560. , Brassard P. and Fontaine G. ed G. Chabrier and E. Schatzman (Cambridge: Cambridge Univ. Press)
Gillon, M., Jehin, E., Lederer, S.M., (2016) Natur, 533, p. 221
Gillon, M., Jehin, E., Magain, P., (2011) EPJWC, 11, p. 06002
Gillon, M., Triaud, A.H.M.J., Demory, B.-O., (2017) Natur, 542, p. 456
Grevesse, N., Noels A.ed Prantzos, N., Vangioni-Flam E.and Casse, M., (1993) Origin and Evolution of the Elements, p. 15. , Grevesse N. and Noels A. ed N. Prantzos, E. Vangioni-Flam and M. Casse (Cambridge: Cambridge Univ. Press)
Gustafsson, B., Edvardsson, B., Eriksson, K., (2008) A&A, 486, p. 951
Kitsikis, A., Fontaine, G., Brassard P.ed Koester D.and Moehler, S., (2005) ASP Conf. Ser. 334, 14th European Workshop on White Dwarfs, p. 65. , Kitsikis A., Fontaine G. and Brassard P. ed D. Koester and S. Moehler (San Francisco, CA: ASP)
Lamb, D.Q., Jr., (1974) PhD Thesis, , Lamb D. Q. Jr. The Univ. Rochester
Lindgren, S., Heiter, U., (2017) A&A, 604, p. A97
Mann, A.W., Deacon, N.R., Gaidos, E., (2014) AJ, 147 (6), p. 160