Radial-velocity Searches for Planets Around Active Stars

Beschreibung

This thesis develops new and powerful methods for identifying planetary signals in the presence of “noise” generated by stellar activity, and explores the physical origin of stellar intrinsic variability, using unique observations of the Sun seen as a star. In particular, it establishes that the intrinsic stellar radial-velocity variations mainly arise from suppression of photospheric convection by magnetic fields. With the advent of powerful telescopes and instruments we are now on the verge of discovering real Earth twins in orbit around other stars. The intrinsic variability of the host stars themselves, however, currently remains the main obstacle to determining the masses of such small planets. The methods developed here combine Gaussian-process regression for modeling the correlated signals arising from evolving active regions on a rotating star, and Bayesian model selection methods for distinguishing genuine planetary signals from false positives produced by stellar magnetic activity.The findings of this thesis represent a significant step towards determining the masses of potentially habitable planets orbiting Sun-like stars. 

This thesis develops new and powerful methods for identifying planetary signals in the presence of “noise” generated by stellar activity, and explores the physical origin of stellar intrinsic variability, using unique observations of the Sun seen as a star. In particular, it establishes that the intrinsic stellar radial-velocity variations mainly arise from suppression of photospheric convection by magnetic fields. With the advent of powerful telescopes and instruments we are now on the verge of discovering real Earth twins in orbit around other stars. The intrinsic variability of the host stars themselves, however, currently remains the main obstacle to determining the masses of such small planets. The methods developed here combine Gaussian-process regression for modeling the correlated signals arising from evolving active regions on a rotating star, and Bayesian model selection methods for distinguishing genuine planetary signals from false positives produced by stellar magnetic activity.
The findings of this thesis represent a significant step towards determining the masses of potentially habitable planets orbiting Sun-like stars. 
Nominated as an outstanding Ph.D. thesis by the University of St. Andrews, UK Includes clear explanations, making it easy to read and accessible to a broad audience with minimum scientific background knowledge Presents a new, state-of-the-art technique that is expected to become mainstream in planet-hunting research over the next few years Demonstrates that the radial-velocity variations mainly arise from suppression of photospheric convection by magnetic fields. This finding represents a significant step towards measuring the masses of potentially habitable planets orbiting Sun-like stars Includes supplementary material: sn.pub/extras

Autor*in

Raphaëlle D. Haywood

Themen in »Radial-velocity Searches for Planets Around Active Stars«

Exoplanet (extra-solar planet) Detection Exoplanet Characterisation Exoplanet Mass Determination Sun-like Stars Starspots Radial-velocity Searches Stellar Activity Stellar Radial-velocity Variability Search for Other Earths Low-mass Exoplanets

Stimmen zu »Radial-velocity Searches for Planets Around Active Stars«

Details

Link teilen