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

Investigation of period-color (PC) and amplitude-color (AC) relations at themaximum and minimum light can be used to probe the interaction of the hydrogenionization front (HIF) with photosphere and the radiation hydrodynamics of theouter envelopes of Cepheids and RR Lyraes. For example, theoreticalcalculations indicated that such interactions would occur at minimum light forRR Lyrae and result in a flatter PC relation. In the past, the PC and ACrelations have been investigated by using either the $(V-R)_{MACHO}$ or $(V-I)$colors. In this work, we extend previous work to other bands by analyzing theRR Lyraes in the Sloan Digital Sky Survey Stripe 82 Region. Multi-epoch data isavailable for RR Lyraes located within the footprint of the Stripe 82 Region infive ($ugriz$) bands. We present the PC and AC relations at maximum and minimumlight in four colors: $(u-g)_0$, $(g-r)_0$, $(r-i)_0$ and $(i-z)_0$, after theyare corrected for extinction. We found that the PC and AC relations for thissample of RR Lyraes show a complex nature in the form of flat, linear orquadratic relations. Furthermore, the PC relations at minimum light forfundamental mode RR Lyrae stars are separated according to the Oosterhoff type,especially in the $(g-r)_0$ and $(r-i)_0$ colors. If only considering theresults from linear regressions, our results are quantitatively consistent withthe theory of HIF-photosphere interaction for both fundamental and firstovertone RR Lyraes.

Period-Color and Amplitude-Color Relations at Maximum and Minimum Light for RR Lyrae Stars in the SDSS Stripe 82 Region