title: Stellar Imaging and Spectroscopy for the Discovery of Extrasolar Planets
creator: Brems, Stefan Sebastian
subject: ddc-520
subject: 520 Astronomy and allied sciences
description: Observing planets during their formation is a challenging, but also important task if one wants to learn about their evolution. In this thesis I explain how I have contributed to various direct imaging surveys, as well as the RVSPY radial velocity survey, which aim at finding planets around young stars. The contributions include appropriate target selection, data analysis and calibration of the instruments, in particular for the NaCo-ISPY and RVSPY surveys. I present systems I analyzed throughout the course of the NaCo-ISPY direct imaging survey which showed promising signals. Further investigation showed that all signals are most likely not caused by physical companions – with the exception of HD 101412, which is a good candidate for a system composed of a star orbited by two brown dwarfs or low mass stellar objects (< 0.1 solar masses). I explain what makes us believe this and what are our next steps to conclude on the system's nature. Further I present the current status as well as some early results of the recent RVSPY survey.    I also present results from the analysis of stellar radial velocity jitter as function of age and observational timescale. The main result is a greater than exponential decrease of the radial velocity jitter with increasing stellar age. Additionally the radial velocity jitter increases by about a factor of two when probing timescales of years instead of hours or days.
date: 2019
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/26787/1/Thesis_Brems_20190513.pdf
identifier: DOI:10.11588/heidok.00026787
identifier: urn:nbn:de:bsz:16-heidok-267876
identifier:   Brems, Stefan Sebastian  (2019) Stellar Imaging and Spectroscopy for the Discovery of Extrasolar Planets.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/26787/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng