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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Ultraviolet observations of Ultra-hot Jupiters (UHJs), exoplanets withtemperatures over 2000\,K, provide us with an opportunity to investigate if andhow atmospheric escape shapes their upper atmosphere. Near-ultraviolet transitspectroscopy offers a unique tool to study this process owing to the presenceof strong metal lines and a bright photospheric continuum as the light sourceagainst which the absorbing gas is observed. WASP-189b is one of the hottestplanets discovered to date, with a day-side temperature of about 3400\,Korbiting a bright A-type star. We present the first near-ultravioletobservations of WASP-189b, acquired with the Colorado Ultraviolet TransitExperiment ($CUTE$). $CUTE$ is a 6U NASA-funded ultraviolet spectroscopymission, dedicated to monitoring short-period transiting planets. WASP-189b wasone of the $CUTE$ early science targets and was observed during threeconsecutive transits in March 2022. We present an analysis of the $CUTE$observations and results demonstrating near-ultraviolet (2500--3300~\AA)broadband transit depth ($1.08^{+0.08}_{-0.08}\%$) of about twice the visualtransit depth indicating that the planet has an extended, hot upper atmospherewith a temperature of about 15000\,K and a moderate mass loss rate of about\SI{4e8}{\kg\per\second}. We observe absorption by Mg{\sc ii} lines ($R_p/R_s$of $0.212^{+0.038}_{-0.061}$) beyond the Roche lobe at $>$4$\sigma$significance in the transmission spectrum at a resolution of 10~\AA, while atlower resolution (100~\AA), we observe a quasi-continuous absorption signalconsistent with a "forest" of low-ionization metal absorption dominated byFe{\sc ii}. The results suggest an upper atmospheric temperature($\sim15000$\,K), higher than that predicted by current state-of-the-arthydrodynamic models.

CUTE reveals escaping metals in the upper atmosphere of the ultra-hot Jupiter WASP-189b