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 study the $\delta$ Scuti -- red giant binary KIC9773821, the firstdouble-pulsator binary of its kind. It was observed by \textit{Kepler} duringits four-year mission. Our aims are to ascertain whether the system is bound,rather than a chance alignment, and to identify the evolutionary state of thered giant via asteroseismology. An extension of these aims is to determine adynamical mass and an age prior for a $\delta$ Sct star, which may permit modeidentification via further asteroseismic modelling. We determine spectroscopicparameters and radial velocities (RVs) for the red giant component usingHERMES@Mercator spectroscopy. Light arrival-time delays from the $\delta$ Sctpulsations are used with the red-giant RVs to determine that the system isbound and to infer its orbital parameters, including the binary mass ratio. Weuse asteroseismology to model the individual frequencies of the red giant togive a mass of $2.10^{+0.20}_{-0.10}$ M$_{\odot}$ and an age of$1.08^{+0.06}_{-0.24}$ Gyr. We find that it is a helium-burning secondary clumpstar, confirm that it follows the standard $\nu_{\rm max}$ scaling relation,and confirm its observed period spacings match their theoretical counterpartsin the modelling code MESA. Our results also constrain the mass and age of the$\delta$ Sct star. We leverage these constraints to construct $\delta$ Sctmodels in a reduced parameter space and identify four of its five pulsationmodes.

A binary with a $\delta$~Scuti star and an oscillating red giant: orbit and asteroseismology of KIC9773821