On the Track of Alien Planets – Direct Imaging and Observation (∼2.9% of All Exoplanet Primary Discoveries or ∼6% if Free Floating Planets are Included)

Abstract

Unlike the Doppler and transit approaches to discovering exoplanets with their inbuilt biases towards discovering hot Jupiters, finding exoplanets by direct observation is biased towards detecting exoplanets that are a long way out from their host stars. Thus the orbital radii of those directly observed exoplanets currently known ranges from at least 4 to nearly 700 AU – several thousand times further from their host stars than most of the exoplanets considered up to now. The reason for this bias is obvious – the light from the much brighter star swamps the light from the exoplanet unless they are well separated from each other.