<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Physical Characterization of Brown Dwarfs"^^ . "The initial mass function describes the distribution of masses for a population of stars and substellar\r\nobjects when they are born. It defines the evolution of a population of stars and provides\r\nconstrains on the star formation theory. The determination of the initial mass function in the substellar\r\nregime is still an open question in Astrophysics. Brown dwarfs do not have enough mass\r\nto sustain hydrogen fusion. As a consequence, mass and age are degenerate for these objects. An\r\nolder high mass object may be indistinguishable from a younger low mass object. In this PhD\r\nthesis, through the characterization of brown dwarfs using several observational methods, I work\r\ntowards solving the general problem of constraining the substellar initial mass function.\r\nIn my first project, I calculated trigonometric parallaxes of a sample of six cool brown dwarfs. I\r\ndetermined the luminosity for our objects and I found that one of them might be a brown dwarf\r\nbinary. In my second project, I confirmed the youth of seven brown dwarfs (ages between 1 and\r\n150 Myr) using spectroscopic data. In the last project of this PhD thesis, I aimed to refine the\r\nbrown dwarf binary fraction using spectroscopic data in the optical and in the near infrared for\r\n22 brown dwarfs. I found six new brown dwarf binary candidates, two of them were previously\r\nknown. The determination of distances, ages and the refinement of the brown dwarf binary\r\nfraction in this PhD thesis contribute to the determination of the initial mass function.\r\nIn the next years, the Gaia satellite, the JamesWebb Space Telescope and the E-ELT will provide\r\nnew data, allowing the discovery of new brown dwarf binaries, the constraining of atmospheric\r\nand evolutionary models, and the refinement of the intial mass function."^^ . "2015" . . . . . . . "Elena"^^ . "Manjavacas"^^ . "Elena Manjavacas"^^ . . . . . . "Physical Characterization of Brown Dwarfs (PDF)"^^ . . . "thesis_elena.pdf"^^ . . . "Physical Characterization of Brown Dwarfs (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Physical Characterization of Brown Dwarfs (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Physical Characterization of Brown Dwarfs (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Physical Characterization of Brown Dwarfs (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Physical Characterization of Brown Dwarfs (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #18208 \n\nPhysical Characterization of Brown Dwarfs\n\n" . "text/html" . . . "520 Astronomie"@de . "520 Astronomy and allied sciences"@en . . . "530 Physik"@de . "530 Physics"@en . .