Modeling the Cloudy Atmospheres of Cool Stars, Brown Dwarfs and Hot Exoplanets

TY - BOOK

T1 - Modeling the Cloudy Atmospheres of Cool Stars, Brown Dwarfs and Hot Exoplanets

AU - Juncher, Diana

PY - 2016

Y1 - 2016

N2 - M-dwarfs are very attractive targets when searching for new exoplanets. Unfortunately, they are also very difficult to model since their temperatures are low enough for dust clouds to form in their atmospheres. Because the properties of an exoplanet cannot be determined without knowing the properties of its host star, it is crucial that the stellar models linking the observations of a star to its properties are as precise as possible. The primary goal of this project is therefore to merge the model atmosphere code MARCS with the dust model code DRIFT, thus facilitating the computation of self-consistent cloudy atmosphere models that can be used to properly determine the stellar parameters of cool stars.With this enhanced model atmosphere code I have created a grid of cool, dusty atmosphere models ranging in effective temperatures from Teff = 2000 − 3000 K. I have studied the formation and structure of their clouds and found that their synthetic spectra fit the observed spectra of mid to late type M-dwarfs and early type L-dwarfs well. With additional development into even cooler regimes, they could be used to characterize the atmospheres of exoplanets and aid us in our search for the kind of chemical imbalances that suggest the presence of life.I have also directly performed spectroscopic and photometric observations of exoplanets to discover and/or improve our knowledge of their properties and to participate in the development of the techniques that is being used to discover and characterize exoplanets."

AB - M-dwarfs are very attractive targets when searching for new exoplanets. Unfortunately, they are also very difficult to model since their temperatures are low enough for dust clouds to form in their atmospheres. Because the properties of an exoplanet cannot be determined without knowing the properties of its host star, it is crucial that the stellar models linking the observations of a star to its properties are as precise as possible. The primary goal of this project is therefore to merge the model atmosphere code MARCS with the dust model code DRIFT, thus facilitating the computation of self-consistent cloudy atmosphere models that can be used to properly determine the stellar parameters of cool stars.With this enhanced model atmosphere code I have created a grid of cool, dusty atmosphere models ranging in effective temperatures from Teff = 2000 − 3000 K. I have studied the formation and structure of their clouds and found that their synthetic spectra fit the observed spectra of mid to late type M-dwarfs and early type L-dwarfs well. With additional development into even cooler regimes, they could be used to characterize the atmospheres of exoplanets and aid us in our search for the kind of chemical imbalances that suggest the presence of life.I have also directly performed spectroscopic and photometric observations of exoplanets to discover and/or improve our knowledge of their properties and to participate in the development of the techniques that is being used to discover and characterize exoplanets."

UR - http://rex.kb.dk/KGL:KGL:KGL01009224301

M3 - Ph.D. thesis

BT - Modeling the Cloudy Atmospheres of Cool Stars, Brown Dwarfs and Hot Exoplanets

PB - The Niels Bohr Institute, Faculty of Science, University of Copenhagen

ER -