English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Models of exoplanet atmospheres based on Parker-wind density and velocityprofiles are a common choice in fitting spectroscopic observations tracingplanetary atmospheric escape. Inferring atmospheric properties using thesemodels often results in a degeneracy between the temperature and the mass-lossrate, and thus provides weak constraints on either parameter. We present aframework that can partially resolve this degeneracy by placing more stringentconstraints on the expected thermospheric temperature. We use thephotoionization code Cloudy within an iterative scheme to compute thetemperature structure of a grid of 1D Parker wind models, including the effectsof radiative heating/cooling, as well as the hydrodynamic effects (expansioncooling and heat advection). We constrain the parameter space by identifyingmodels that are not self-consistent through a comparison of the simulatedtemperature in the He 10830 $\r{A}$ line-forming region to the temperatureassumed in creating the models. We demonstrate this procedure on models basedon HD 209458 b. By investigating the Parker wind models with an assumedtemperature between 4000 and 12000 K, and a mass-loss rate between $10^{8}$ and$10^{11}$ g s$^{-1}$, we are able to rule out a large portion of this parameterspace. Furthermore, we fit the models to previous observational data andcombine both constraints to find a preferred thermospheric temperature of$T=8200^{+1200}_{-1100}$ K and a mass-loss rate of$\dot{M}=10^{9.84^{+0.24}_{-0.27}}$ g s$^{-1}$ assuming a fixed atmosphericcomposition and no gas pressure confinement by the stellar wind. Using the sameprocedure, we constrain the temperatures and mass-loss rates of WASP-69 b,WASP-52 b, HAT-P-11 b, HAT-P-18 b and WASP-107 b.

Constraining planetary mass-loss rates by simulating Parker wind profiles with Cloudy