Probability of the Presence of Undetected Brown Dwarfs in the Solar Vicinity

Based on the spatial distribution of objects in the solar vicinity with a radius of 20 pc and after correcting for incomplete observational data, an expression for estimating the probability of finding an object at a certain distance from the Sun has been derived. According to these estimates, there is a probability of ~ 1pt 0.5 that a brown dwarf exists in the immediate solar vicinity ( < 1pt 1.2 pc). The possible multiplicity of this hypothetical object, as well as the reasons why it has not yet been detected, has been discussed. The paper is partially based on a report presented at the conference Modern Stellar Astronomy—2025.