Physical Characterization of Brown Dwarfs
2015
The initial mass function describes the distribution of masses for a population of stars and substellar
objects when they are born. It defines the evolution of a population of stars and provides
constrains on the star formation theory. The determination of the initial mass function in the substellar
regime is still an open question in Astrophysics. Brown dwarfs do not have enough mass
to sustain hydrogen fusion. As a consequence, mass and age are degenerate for these objects. An
older high mass object may be indistinguishable from a younger low mass object. In this PhD
thesis, through the characterization of brown dwarfs using several observational methods, I work
towards solving the general problem of constraining the substellar initial mass function.
In my first project, I calculated trigonometric parallaxes of a sample of six cool brown dwarfs. I
determined the luminosity for our objects and I found that one of them might be a brown dwarf
binary. In my second project, I confirmed the youth of seven brown dwarfs (ages between 1 and
150 Myr) using spectroscopic data. In the last project of this PhD thesis, I aimed to refine the
brown dwarf binary fraction using spectroscopic data in the optical and in the near infrared for
22 brown dwarfs. I found six new brown dwarf binary candidates, two of them were previously
known. The determination of distances, ages and the refinement of the brown dwarf binary
fraction in this PhD thesis contribute to the determination of the initial mass function.
In the next years, the Gaia satellite, the JamesWebb Space Telescope and the E-ELT will provide
new data, allowing the discovery of new brown dwarf binaries, the constraining of atmospheric
and evolutionary models, and the refinement of the intial mass function.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
0
Citations
NaN
KQI