The establishment of the luminosity function for brown dwarf candidates in GAIA Early Data Release 3

Abstract

Brown dwarfs are classified as objects with masses between that of stars and planets. First theorized in the 1960s, they remained an elusive target for detection until the mid 1990s since they have no sustainable energy source therefore causing them to cool and become less luminous over time. With the advent of more sophisticated telescopes, such as GAIA, astronomers have been able to probe to higher magnitudes/lower luminosities leading to the discovery of numerous confirmed brown dwarfs over the past two decades. Here, I examine the luminosity function from a set of brown dwarf candidates derived from GAIA’s Catalogue of Nearby Stars (GCNS) by applying a classical technique that makes use of the space density over defined intervals of absolute magnitudes. I then present a comparison between GAIA’s observational luminosity function and predictions from current brown dwarf models for both metal poor and metal rich objects. I find that GAIA is a great tool for investigating the properties of objects surrounding the critical hydrogen burning minimum mass but does not penetrate deep into the brown dwarf regime due to absolute magnitude limitations of the spacecraft. I also highlight the importance of metallicity when classifying objects near the stellar/substellar boundary and find that small variations can significantly alter this boundary.