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

The census of stellar and substellar companions of nearby stars is largelyincomplete. It is, however, fundamentally important in the understanding of thestellar and planetary formation and evolution mechanisms. We aim tocharacterize the presence of physical companions in orbit around nearby stars.Orbiting secondary bodies influence the proper motion (PM) of their parent starthrough their gravitational reflex motion. Using the Hipparcos catalog andGaia's second data release (GDR2), we determined the long-term PM of the starscommon to these two catalogs. We then searched for a PM anomaly (PMa) betweenthe long-term PM vector and the GDR2 (or Hipparcos) measurements, indicative ofthe presence of a perturbing secondary object. We focussed our analysis on the6741 nearby stars located within 50 pc, and we also present a catalog of thePMa for >99% of the Hipparcos catalog (>117000 stars). 30% of the stars studiedpresent a PMa greater than 3 sigmas. The PMa allows us to detect orbitingcompanions, or set stringent limits on their presence. We present a fewapplications to interesting targets. We set upper limits of 0.1-0.3 M_Jup topotential planets orbiting Proxima between 1 and 10 au (P_orb=3 to 100 years).We confirm that Proxima is gravitationally bound to alpha Cen. We recover themasses of the known companions of epsilon Eri, epsilon Ind, Ross 614 and betaPic. We also detect a possible planet of a few Jovian masses orbiting tau Ceti.The combination of the GDR2 with Hipparcos results in very high accuracy PMavectors. The detection of tangential velocity anomalies at a median accuracy ofsigma(Delta v_tan)=1.0 m/s per parsec of distance opens the possibility toidentify long period orbital companions otherwise inaccessible. Gaia'scomplementarity to radial velocity and transit techniques already appears to beremarkably powerful.

Stellar and substellar companions of nearby stars from Gaia DR2 - Binarity from proper motion anomaly