A new RR Lyrae Star in Segue 2
American Astronomical Society, AAS Meeting #221, id.316.02
Published in Jan 2013
We present a newly discovered fundamental mode (RRab) RR Lyrae star in the ultra-faint Milky Way dwarf galaxy companion Segue 2 (L ̃ 830 Lsun). We perform a near complete search for RR Lyrae in Segue 2 using Harris B and V band imaging taken at Kitt Peak National Observatory's 0.9 meter WIYN telescope. A very low metallicity for the RRab star ([Fe/H] 〈̃ -2.5) is hinted at by the length of the RRab star's period (Pab = 0.749 days). The RRab star as well as spectroscopically confirmed blue horizontal branch stars belonging to Segue 2 allow us to rigorously determine the distance to this object. Assuming a low metallicity ([Fe/H] = -2.5) for both the RRab and BHB stars, we find distances consistent within one standard deviation of dRRL = 37.9+2.8-2.7 kpc and dBHB = 35.2 ± 2.6 kpc. We gratefully acknowledge NSF AST-0908193 for support.
(c) 2013: American Astronomical Society