21 - Searches for brown dwarfs

Summary

Abstract

This review attempts a brief summary of the numerous and diverse searches for the so-called brown dwarfs, substellar objects having masses between giant planets and the lowest mass M dwarf stars.

Cette revue donne un bref aperçu de l'état actuel des diverses recherches de naines brunes, objects substellaires ayant des masses comprises entre les planètes géantes et les naines M de faible masse.

Introduction

Between the giant planets such as Jupiter (10⁻³M_⊙) and stars at the bottom of the hydrogen-burning main sequence (≤0.1M_⊙) – spanning more than two orders of magnitude in mass – the sequence of brown dwarfs has yet to be discovered and analyzed in detail. The previous sentence carries the positive bias of this author that – despite the current lack of a single, unambiguous example for me to discuss at this meeting – the flurry of searches now underway by a variety of techniques will identify at least some genuine brown dwarfs during the present decade. Our motivation for thinking and speaking positively is to encourage advances in the theory of both the interiors and atmospheres of such gaseous objects, in order to make possible positive identifications among the candidates found by observers. Indeed, numerous candidates exist of different kinds, some with measured masses, luminosities and temperatures which straddle the stellar mass limit (SML) near 0.08 M_⊙.