On the origin and nature of brown dwarfs and massive planets [Elektronische Ressource] / vorgelegt von Ingo Thies

On the origin and nature of browndwarfs and massive planetsDissertationzurErlangung des Doktorgrades (Dr. rer. nat)derMathematisch-Naturwissenschaftlichen Fakult atderRheinischen Friedrich-Wilhelms-Universit at Bonnvorgelegt vonIngo ThiesausNiebullBonn, 2010Angefertigt mit Genehmigung der Mathematisch-Naturwissenschaftlichen Fakult at derRheinischen Friedrich-Wilhelms-Universit at Bonn.1. Referent: Prof. Dr. P. Kroupa2.t: Prof. Dr. R. IzzardTag der Promotion: 9. Februar 2011Erscheinungsjahr: 2011I believe in intuition and inspiration. Imagination is more important than knowledge.For knowledge is limited, whereas imagination embraces the entire world, stimulatingprogress, giving birth to evolution. It is, strictly speaking, a real factor in scienti cresearch.Albert EinsteinTo all the people who will have leftthis universe before the universewill leave usSummaryIn this thesis the apparent peculiarities of brown dwarfs (BDs) are pointed out whichforce us to treat them as a population apart from, but yet still related to the stellarpopulation. In particular, the properties that make BDs so special are deduced fromthe observational evidence in Chapter 1: 1. The brown dwarf desert, i.e. the apparentdearth of substellar, non-planetary companions to stars, 2. the truncated distributionof the semi-major axes of BD-BD binaries (Fig. 1.1), 3. the unusually top-heavy massratio distribution of BD-BD binaries, compared to star-star binaries (Fig. 1.