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

Aims. I look for and characterise very wide binaries and multiple systemswith projected physical separations larger than s = 0.1 pc, which is generallybelieved to be a sharp upper limit to the distribution of wide binay semimajoraxes. Methods. I investigated in detail 30 Washington Double Stars with angularseparations rho > 1000 arcsec. I discarded 23 of them as probably unboundsystems based on discordant astrometry, photometry, spectral types, and radialvelocities. The remaining seven systems were subject to a comprehensive datacompilation and derivation (multi-wavelength photometry, heliocentric distance,multiplicity, age, mass, metallicity, membership in young kinematic group).Results. Of the seven very wide systems, six have projected physicalseparations larger than the hypothetical cutoff at s = 0.1 pc; four of themhave separations s > 0.2 pc. Although there are two systems in young kinematicgroups (namely HD 136654 and BD+32 2572 in the Hyades Supercluster, and AU Micand AT Mic AB in the beta Pictoris moving group), there is not a clearprevalence of young systems (tau < 1 Ga) among these very wide binaries.Finally, I compare the binding energies of the seven systems with those ofother weakly bound systems in the field.

Reaching the boundary between stellar kinematic groups and very wide binaries. The Washington Double Stars with the widest angular separations