Unlisted RR Lyrae type ab - KIC 1570352

UKIRT image showing direction (green) of RR Lyrae from target star by Kian Jek

Planet Hunters forum Talk members Dolorous EDD and Zoo3hans flagged a background RR Lyrae type ab star that was contaminating the the Kepler light curve for star KIC 1570349 below:

zoo3hans:

The LC shows massive variation through the different quarters, so I assume it's contamination. It could be a background RR_Lyrae type star.

Kian Jek:
 

kianjin

Yes indeed Hans, it's very likely contamination from a BG RRLab. Here's the phased curve which matches the profile of an RRLab in period but the amplitude is too low - it should be at least 80% or more at the peak:

APOs show the flux centroid shifting during the variation.

These can be traced to the nearby star KIC 1570352, a magnitude 18.4 star. There isn't much in the way of stellar characteristics known, but the g-r value of 0.175 suggests a Type AF star, with a Teff around 7000K, which makes it just right for an RRLab.

 Chris Lintott:

zookeeper (moderator)

 

I've been in touch with Robert Szabo, our resident guru for such things, and he confirms this is a new discovery of a RRLyr of type ab - fabulous stuff and congratulations to all involved.

You can follow the discussion on this star at Planet Hunters forum Talk here.