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

Although the main goal of the Transiting Exoplanet Survey Satellite(\textit{TESS}) is to search for new transiting exoplanets, its data can alsobe used to study in further detail already known systems. The \textit{TESS}bandpass is particularly interesting to study the limb-darkening effect of thestellar host which is imprinted in transit lightcurves, as the widely used\textsc{phoenix} and \textsc{atlas} stellar models predict differentlimb-darkening profiles. Here we study this effect by fitting the transitlightcurves of 176 known exoplanetary systems observed by \textit{TESS}, whichallows us to extract empirical limb-darkening coefficients (LDCs) for thewidely used quadratic law, but also updated transit parameters (includingephemerides refinements) as a byproduct. Comparing our empirically obtainedLDCs with theoretical predictions, we find significant offsets when usingtabulated \textit{TESS} LDCs. Specifically, the $u_2$ coefficients obtainedusing \textsc{phoenix} models show the largest discrepancies depending on themethod used to derive them, with offsets that can reach up to $\Delta u_2\approx 0.2$ on average. Most of those average offsets disappear, however, ifone uses the SPAM algorithm introduced by Howarth (2011) to calculate the LDCsinstead. Our results suggest, however, that for stars cooler than about 5000 K,no methodology is good enough to explain the limb-darkening effect: we observea sharp deviation between measured and predicted LDCs on both quadratic LDCs oforder $\Delta u_1, \Delta u_2 \approx 0.2$ for those cool stars. We recommendcaution when assuming limb-darkening coefficients as perfectly known thus, inparticular for these cooler stars when analyzing \textit{TESS} transitlightcurves.

Empirical limb-darkening coefficients & transit parameters of known exoplanets from TESS