Mon. Not. R. Astron. Soc., 446, 1268-1282 (2015/January-2)
A search for open cluster Cepheids in the Galactic plane.
CHEN X., DE GRIJS R. and DENG L.
Abstract (from CDS):
We analyse all potential combinations of Galactic Cepheids and open clusters (OCs) in the most up-to-date catalogues available. Isochrone fitting and proper-motion calculation are applied to all potential OC-Cepheid combinations. Five selection criteria are used to select possible OC Cepheids: (i) the Cepheid of interest must be located within 60arcmin of the OC's centre; (ii) the Cepheid's proper motion is located within the 1σ distribution of that of its host OC; (iii) the Cepheid is located in the instability strip of its postulated host OC; (iv) the Cepheid and OC distance moduli should differ by less than 1mag; and (v) the Cepheid and OC ages (and, where available, their metallicities) should be comparable: Δlog(t/yr) < 0.3. 19 possible OC Cepheids are found based on our near-infrared (NIR) analysis; eight additional OC-Cepheid associations may be genuine pairs for which we lack NIR data. Six of the Cepheids analysed at NIR wavelengths are new, high-probability OC Cepheids, since they lie on the NIR period (P)-luminosity relation (PLR). These objects include TY Sct and CN Sct in Dolidze 34, XX Sgr in Dolidze 52, CK Sct in NGC 6683, VY Car in ASCC 61 and U Car in Feinstein 1. Two additional new OC Cepheids lack NIR data: V0520 Cyg in NGC 6991 and CS Mon in Juchert 18. The NIR PLR for our confirmed sample of OC Cepheids is MJ = (-3.12±0.29)log(Pd-1) - (2.17±0.29)mag, which is in good agreement with the best NIR PLR available for all Galactic Cepheids.