title: Analysis of High-Precision Spectroscopic Data in Search of Exoplanet Signals Close to the Stellar Noise Limit
creator: Stock, Stephan Amir
subject: 520
subject: 520 Astronomy and allied sciences
subject: 530
subject: 530 Physics
description: Due to their low mass and low temperature, M-dwarf stars are promising targets for the detection of planets in the host star’s temperate zone with the radial velocity (RV) method. However, M dwarfs typically exhibit stellar activity, producing noise in the RV data which can mask the signals from existing planets or, as well as aliasing caused by data sampling, can lead to false candidates or to wrongly determined planetary parameters. I present RV analyses for four M dwarfs with the aim of detecting and characterizing potential planetary signals.  To overcome the aliasing problems, I developed the public tool AliasFinder, which is an improvement of an already known method for distinguishing aliases from actual signals. For the disentanglement of stellar activity and planetary signals, and for their modeling, I used current state-of-the-art analysis techniques, e.g., Bayesian statistics and Gaussian process (GP) regression. The properties and the performance of GP models have been investigated and tested on simulated RV data of active M dwarfs. These GP models, along with additional data taken by CARMENES, have resulted in improved planetary parameters for four previously known planets (the multiplanetary system YZ Ceti and the single-planet system of Lalande 21185) and two new planet discoveries (the temperate super-Earth GJ 251 b and the warm super-Earth HD 238090 b). The analyses, results,and partially unique approaches in this thesis demonstrate that it is possible to detect and model planetary RV signals at the limit of the stellar astrophysical noise by applying rigorous statistical models, along with prior information from auxiliary data and further simulations.
date: 2021
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/29962/1/Dissertation_Stephan_Stock_final_HGSFP.pdf
identifier: DOI:10.11588/heidok.00029962
identifier: urn:nbn:de:bsz:16-heidok-299629
identifier:   Stock, Stephan Amir  (2021) Analysis of High-Precision Spectroscopic Data in Search of Exoplanet Signals Close to the Stellar Noise Limit.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/29962/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng