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 report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based ondata from NASA's Transiting Exoplanet Survey Satellite (TESS). The transitsignal was detected by TESS and confirmed to be of planetary origin based onradial velocity observations. An analysis of the TESS photometry, theMinerva-Australis, FEROS, and HARPS radial velocities, and the asteroseismicdata of the stellar oscillations reveals that TOI-257b has a mass of$M_P=0.138\pm0.023$\,$\rm{M_J}$ ($43.9\pm7.3$\,$M_{\rm \oplus}$), a radius of$R_P=0.639\pm0.013$\,$\rm{R_J}$ ($7.16\pm0.15$\,$R_{\rm \oplus}$), bulk densityof $0.65^{+0.12}_{-0.11}$ (cgs), and period$18.38818^{+0.00085}_{-0.00084}$\,$\rm{days}$. TOI-257b orbits a bright($\mathrm{V}=7.612$\,mag) somewhat evolved late F-type star with$M_*=1.390\pm0.046$\,$\rm{M_{\odot}}$, $R_*=1.888\pm0.033$\,$\rm{R_{\odot}}$,$T_{\rm eff}=6075\pm90$\,$\rm{K}$, and $v\sin{i}=11.3\pm0.5$\,km\,s$^{-1}$.Additionally, we find hints for a second non-transiting sub-Saturn mass planeton a $\sim71$\,day orbit using the radial velocity data. This system joins theranks of a small number of exoplanet host stars ($\sim100$) that have beencharacterized with asteroseismology. Warm sub-Saturns are rare in the knownsample of exoplanets, and thus the discovery of TOI-257b is important in thecontext of future work studying the formation and migration history of similarplanetary systems.

TOI-257b (HD 19916b): A Warm sub-Saturn Orbiting an Evolved F-type Star