Spectroscopic iron-to-hydrogen ratios , radial velocities , atmospheric parameters , and new photometric analyses are presented for 41 RR Lyrae stars ( and one probable high-amplitude \delta Sct star ) located in the field-of-view of the Kepler space telescope .
Thirty-seven of the RR Lyrae stars are fundamental-mode pulsators ( i.e . , RRab stars ) of which 16 exhibit the Blazhko effect .
Four of the stars are multiperiodic RRc pulsators oscillating primarily in the first-overtone mode .
Spectroscopic [ Fe/H ] values for the 34 stars for which we were able to derive estimates range from -2.54 \pm 0.13 ( NR Lyr ) to -0.05 \pm 0.13 dex ( V784 Cyg ) , and for the 19 Kepler -field non-Blazhko stars studied by Nemec et al . ( 2011 ) the abundances agree will with their photometric [ Fe/H ] values .
Four non-Blazhko RR Lyrae stars that they identified as metal-rich ( KIC 6100702 , V2470 Cyg , V782 Cyg and V784 Cyg ) are confirmed as such , and four additional stars ( V839 Cyg , KIC 5520878 , KIC 8832417 , KIC 3868420 ) are also shown here to be metal-rich .
Five of the non-Blazhko RRab stars are found to be more metal-rich than [ Fe/H ] \sim - 0.9 dex while all of the 16 Blazhko stars are more metal-poor than this value .
New P - \phi _ { 31 } ^ { s } - [ Fe/H ] relationships are derived based on \sim 970 days of quasi-continuous high-precison Q0-Q11 long- and short-cadence Kepler photometry .
With the exception of some Blazhko stars , the spectroscopic and photometric [ Fe/H ] values are in good agreement .
Several stars with unique photometric characteristics are identified , including a Blazhko variable with the smallest known amplitude and frequency modulations ( V838 Cyg ) .