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

Magnetic star-planet interactions (SPI) provide a detection method andinsight into exoplanet magnetic fields and, in turn, exoplanet interiors andatmospheric environments. These signatures can be sporadic and difficult toconfirm for single-epoch observations of a system due to inhomogeneous stellarmagnetospheres and periodic variability in stellar magnetism. Thus an ideal SPIsearch consists of multiple epochs containing observations on consecutivenights spanning at least one complete planetary orbit. Such data sets are rarebut do exist for some of the most intensely studied hot Jupiter systems. Onesuch system is HD 189733 for which six suitable SPI data sets exist, the resultof spectroscopic monitoring to perform some of the first SPI searches and alsoto study the star's magnetic field. Here we perform a uniform analysis of sixarchival Ca II K data sets for HD 189733, spanning 2006 June through 2015 July,in order to search for magnetic SPI signatures in the chromospheric linevariations. We find significant evidence for modulations of Ca II K with a$2.29\pm0.04$ day period in the 2013 August data, which is consistent with theplanet's orbital period. The peak in the orbital variations occurs at$\phi_\text{orb} \approx 0.9$, which corresponds to the SPI emission leadingthe planet with a phase difference of $\Delta\phi \approx 40^\circ$ from thesub-planetary point. This is consistent with the phase lead predictions ofnon-linear force-free magnetic field SPI models. The stellar magnetic fieldstrength at the planet's orbit is greatest in 2013 August which, due to theenergy released in magnetic SPI scaling with $B_*$, lends strength to the SPIinterpretation.

Evidence of magnetic star-planet interactions in the HD 189733 system from orbitally-phased Ca II K variations