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

We developed a new approach to provide accurate estimates of metal content,reddening and true distance modulus of RR Lyrae stars (RRLs). The method isbased on homogeneous optical ($BVI$) and near-infrared ($JHK$) mean magnitudesand on predicted period--luminosity--metallicity relations ($IJHK$) andabsolute mean magnitude--metallicity relations ($BV$). We obtained solutionsfor three different RRL samples in $\omega$ Cen: first overtone (RRc,~90),fundamental (RRab,~80) and global (RRc+RRab) in which the period of firstovertones were fundamentalized. The metallicity distribution shows a welldefined peak at [Fe/H]$\sim$--1.98 and a standard deviation of $\sigma$=0.54dex. The spread is, as expected, metal-poor ([Fe/H]$\le$--2.3) objects. Thecurrent metallicity distribution is $\sim$0.3 dex more metal-poor than similarestimates for RRLs available in the literature. The difference vanishes if thetrue distance modulus we estimated is offset by --0.06/--0.07~mag in truedistance modulus. We also found a cluster true distance modulus of$\mu$=13.720$\pm$0.002$\pm$0.030~mag, where the former error is the error onthe mean and the latter is the standard deviation. Moreover, we found a clusterreddening of E($B-V$)=0.132$\pm$0.002$\pm$0.028~mag and spatial variations ofthe order of a few arcmin across the body of the cluster. Both the truedistance modulus and the reddening are slightly larger than similar estimatesavailable in the literature, but the difference is within 1$\sigma$. Themetallicity dependence of distance diagnostics agree with theory andobservations, but firm constraints require accurate and homogeneousspectroscopic measurements.

astrophysical journal/the astrophysical journal

On a new method to estimate distance, reddening and metallicity of RR  Lyrae stars using optical/near-infrared ($B$,$V$,$I$,$J$,$H$,$K$) mean  magnitudes: $\omega$ Centauri as a first test case