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/

Zendy Plus

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

Zendy Tools

Zendy Open

Direct-imaging exoplanet surveys have discovered a class of 5-20 \Mjup\spacesubstellar companions at separations >100 AU from their host stars, whichpresent a challenge to planet and star formation models. Detailed analysis ofthe orbital architecture of these systems can provide constraints on possibleformation mechanisms, including the possibility they were dynamically ejectedonto a wide orbit. We present astrometry for the wide planetary-mass companionGSC~6214-210\,b (240 AU; $\approx$14 \Mjup) obtained using NIRC2 with adaptiveoptics at the Keck telescope over ten years. Our measurements achievedastrometric uncertainties of $\approx$1 mas per epoch. We determined a relativemotion of $1.12 \pm 0.15$~mas~yr$^{-1}$ (0.61 $\pm$ 0.09 km s$^{-1}$), thefirst detection of orbital motion for this companion. We compute the minimumperiastron for the companion due to our measured velocity vector, and deriveconstraints on orbital parameters through our modified implementation of theOrbits for the Impatient rejection sampling algorithm. We find that closeperiastron orbits, which could indicate the companion was dynamicallyscattered, are present in our posterior but have low likelihoods. For allorbits in our posterior, we assess the detectability of close-in companionsthat could have scattered GSC~6214-210\,b from a closer orbit, and find thatmost potential scatterers would have been detected in previous imaging. Weconclude that formation at small orbital separation and subsequent dynamicalscattering through interaction with another potential close-in object is anunlikely formation pathway for this companion. We also update stellar andsubstellar properties for the system due to the new parallax from \textit{Gaia}DR2.

Orbital Motion of the Wide Planetary-Mass Companion GSC 6214-210 b: No Evidence for Dynamical Scattering