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 old and metal rich open cluster NGC 6253 was observed with the FLAMESmulti-object spectrograph during an extensive radial velocity campaignmonitoring 317 stars with a median of 15 epochs per object. All the targetedstars are located along the upper main sequence of the cluster between 14.8 $<$V $<$ 16.5. Fifty nine stars are confirmed cluster members both by radialvelocities and proper motions and do not show evidence of variability. Wedetected 45 variable stars among which 25 belong to NGC 6253. We were able toderive an orbital solution for 4 cluster members (and for 2 field stars)yielding minimum masses in between $\sim$90 M$\rm_J$ and $\sim$460 M$\rm_J$ andperiods between 3 and 220 days. Simulations demonstrated that this survey wassensitive to objects down to 30 M$\rm_J$ at 10 days orbital periods with adetection efficiency equal to 50%. On the basis of these results we concludedthat the observed frequency of binaries down to the hydrogen burning limit andup to 20 days orbital period is around (1.5$\pm$1.3)% in NGC 6253. The overallobserved frequency of binaries around the sample of cluster stars is(13$\pm$3)%. The median radial velocity precision achieved by the GIRAFFEspectrograph in this magnitude range was around $\sim$240m$\rm\,s^{-1}$($\sim$180 m$\rm\,s^{-1}$ for UVES). Based on a limited follow-up analysis of 7stars in our sample with the HARPS spectrograph we determined that a precisionof 35 m $\rm s^{-1}$ can be reached in this magnitude range, offering thepossibility to further extend the variability analysis into the substellardomain. Prospects are even more favourable once considering the upcomingESPRESSO spectrograph at VLT.

An extensive radial velocity survey toward NGC 6253