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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The G-type star GJ504A is known to host a 3 to 35 MJup companion whosetemperature, mass, and projected separation all contribute to make it a testcase for the planet formation theories and for atmospheric models of giantplanets and light brown dwarfs. We collected data from the CHARAinterferometer, SOPHIE spectrograph, and VLT/SPHERE high contrast imager torevisit the properties of the system. We measure a radius of 1.35+/- 0.04Rsunfor GJ504A which yields isochronal ages of 21+/-2Myr or 4.0+/-1.8Gyr for thesystem and line-of-sight stellar rotation axis inclination of$162.4_{-4.3}^{+3.8}$ degrees or $18.6_{-3.8}^{+4.3}$ degrees. We re-detect thecompanion in the Y2, Y3, J3, H2, and K1 dual band SPHERE images. The complete1-4 $\mu$m SED shape of GJ504b is best reproduced by T8-T9.5 objects withintermediate ages ($\leq1.5$Gyr), and/or unusual dusty atmospheres and/orsuper-solar metallicities. All six atmospheric models used yield$\mathrm{T_{eff}=550 \pm 50}$K for GJ504b and point toward a low surfacegravity (3.5-4.0 dex). The accuracy on the metallicity value is limited bymodel-to-model systematics. It is not degenerate with the C/O ratio. We derive$\mathrm{log\:L/L_{\odot}=-6.15\pm0.15}$ dex for the companion compatible withmasses of $\mathrm{M=1.3^{+0.6}_{-0.3}M_{Jup}}$ and $\mathrm{M=23^{+10}_{-9}M_{Jup}}$ for the young and old age ranges, respectively. The semi-major axis(sma) is above 27.8 au and the eccentricity lower than 0.55. The posterior onGJ~504b's orbital inclination suggests a misalignment with GJ~504A rotationaxis. We combine the radial velocity and multi-epoch imaging data to excludeadditional objects (90\% prob.) more massive than 2.5 and 30 $\mathrm{M_{Jup}}$with sma in the range 0.01-80 au for the young and old system ages,respectively. The companion is in the envelope of the population of planetssynthetized with our core-accretion model.

The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data