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

$\kappa$CrB is a ${\sim}2.5\,$Gyr old K1 sub-giant star, with an eccentricexo-Jupiter at ${\sim}2.8\,$au and a debris disc at tens of au. We present ALMABand 6 ($1.3\,$mm) and HST scattered light ($0.6\,\mu$m) images, demonstrating$\kappa$CrB's broad debris disc, covering an extent $50{-}180\,$au in themillimetre (peaking at $110\,$au), and $51{-}280\,$au in scattered light(peaking at $73\,$au). By modelling the millimetre emission, we estimate thedust mass as ${\sim}0.016\,M{\oplus}$, and constrain lower-limit planetesimalsizes as $D_{\rm{max}}{>}1\,$km and the planetesimal belt mass as$M_{\rm{disc}}{>}1\,M_{\oplus}$. We constrain the properties of an outer bodycausing a linear trend in 17 years of radial velocity data to have a semi-majoraxis $8{-}66\,$au and a mass $(0.4{-}120)\,M_{\rm{Jup}}$. There is a largeinner cavity seen in the millimetre emission, which we show is consistent withcarving by such an outer massive companion with a string of lower mass planets.Our scattered light modelling shows that the dust must have a high anisotropicscattering factor ($g{\sim}0.8{-}0.9$) but an inclination($i{\sim}30{-}40\,$degrees) that is inferred to be significantly lower than the$i{\sim}61\,$degrees millimetre inclination. The origin of such a discrepancyis unclear, but could be caused by a misalignment in the micron and millimetresized dust. We place an upper limit on the CO gas mass of$M_{\rm{CO}}{<}(4.2{-}13){\times}10^{-7}\,M_{\oplus}$, and show this to beconsistent with levels expected from planetesimal collisions, or from CO-icesublimation as $\kappa$CrB begins its giant branch ascent.

High resolution ALMA and HST imaging of $\kappa$CrB: a broad debris disc around a post-main sequence star with low-mass companions