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

We measured the chromospheric activity of the four hot Jupiter hosts WASP-43,WASP-51/HAT-P-30, WASP-72 & WASP-103 to search for anomalous values caused bythe close-in companions. The Mount Wilson Ca II H&K S-index was calculated foreach star using observations taken with the Robert Stobie Spectrograph at theSouthern African Large Telescope. The activity level of WASP-43 is anomalouslyhigh relative to its age and falls among the highest values of all known mainsequence stars. We found marginal evidence that the activity of WASP-103 isalso higher than expected from the system age. We suggest that for WASP-43 andWASP-103 star-planet interactions (SPI) may enhance the Ca II H&K coreemission. The activity levels of WASP-51/HAT-P-30 and WASP-72 are anomalouslylow, with the latter falling below the basal envelope for both main sequenceand evolved stars. This can be attributed to circumstellar absorption due toplanetary mass loss, though absorption in the ISM may contribute. A quarter ofknown short period planet hosts exhibit anomalously low activity levels,including systems with hot Jupiters and low mass companions. Since SPI canelevate and absorption can suppress the observed chromospheric activity ofstars with close-in planets, their Ca II H&K activity levels are an unreliableage indicator. Systems where the activity is depressed by absorption fromplanetary mass loss are key targets for examining planet compositions throughtransmission spectroscopy.

SALT observations of the Chromospheric Activity of Transiting Planet Hosts: Mass Loss and Star Planet Interactions