J/MNRAS/434/2238 Cepheids in open clusters (Anderson+, 2013) ================================================================================ Cepheids in open clusters: An 8-D all-sky census. Anderson R.I., Eyer L., Mowlavi N. =2013MNRAS.434.2238A ================================================================================ ADC_Keywords: Clusters, open ; Abundances, [Fe/H] ; Positional data ; Parallaxes, trigonometric ; Proper motions ; Radial velocities ; Stars, ages ; Stars, variable ; Stars, distances Keywords: methods: data analysis - astronomical data bases: miscellaneous - catalogs - stars: variables: Cepheids - open clusters and associations: general - distance scale Abstract: Cepheids in open clusters (cluster Cepheids: CCs) are of great importance as zero-point calibrators of the Galactic Cepheid period-luminosity relationship (PLR). We perform an 8-dimensional all-sky census that aims to identify new bona-fide CCs and provide a ranking of membership confidence for known CC candidates according to membership probabilities. The probabilities are computed for combinations of known Galactic open clusters and classical Cepheid candidates, based on spatial, kinematic, and population-specific membership constraints. Data employed in this analysis are taken largely from published literature and supplemented by a year-round observing program on both hemispheres dedicated to determining systemic radial velocities of Cepheids. In total, we find 23 bona-fide CCs, 5 of which are candidates identified for the first time, including an overtone-Cepheid member in NGC 129. We discuss a subset of CC candidates in detail, some of which have been previously mentioned in the literature. Our results indicate unlikely membership for 7 Cepheids that have been previously discussed in terms of cluster membership. We furthermore revisit the Galactic PLR using our bona fide CC sample and obtain a result consistent with the recent calibration by Turner (2010). However, our calibration remains limited mainly by cluster uncertainties and the small number of long-period calibrators. In the near future, Gaia will enable our study to be carried out in much greater detail and accuracy, thanks to data homogeneity and greater levels of completeness. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file tablea2.dat 261 3974 Membership probabilities and data for likelihood computation for all matched Combos clusters.dat 52 990 Cross-matched open clusters cepheids.dat 60 1021 Cross-matched Cepheids refs.dat 157 65 References and comments -------------------------------------------------------------------------------- See also: J/PAZh/25/689 : Young open clusters kinematical parameters (Rastorguev+, 1999) Byte-by-byte Description of file: tablea2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 17 A17 --- Cluster Cluster name 19- 44 A26 --- Cepheid Cepheid name 46- 53 F8.3 arcmin R Separation of Cepheid from cluster center 55- 57 A3 --- r_R Reference used for Cluster radii 59- 66 F8.5 --- prior [0/1] Prior P(A) probability 71- 77 F7.5 --- like [0/1] Likelihood P(B|A) probability 79- 86 F8.5 --- Pmmb [0/1] Membership probability P(A|B) 88- 95 F8.3 mas dplx ? Parallax difference Cluster - Cepheid 97-104 F8.3 mas e_dplx ? Combined error budget for dplx 107-109 A3 --- r_plx0 Reference used for Cluster parallax (1) 111-115 A5 --- r_plx1 Reference used for Cepheid parallax (1) 117-119 A3 --- r_E(B-V)0 Reference used for Cluster E(B-V) (1) 121-124 A4 --- r_E(B-V)1 Reference used for Cepheid E(B-V) (1) 126-130 A5 --- r_Vmag Reference Cluster mean V magnitude (1) 132-135 A4 --- r_Per Reference used for Cepheid Period (1) 137-144 F8.3 km/s dRV ? Radial Velocity difference Cluster - Cepheid 146-153 F8.3 km/s e_dRV ? Combined error budget on dRV 155-158 A4 --- r_RV0 Reference used for Cluster radial velocity (1) 160-163 A4 --- r_RV1 Reference used for Cepheid radial velocity (1) 165-172 F8.3 mas/yr dpmRA ? Proper motion in RA*cos(DE) difference Cluster - Cepheid 174-181 F8.3 mas/yr e_dpmRA ? Combined error budget on dpmRA 183-190 F8.3 mas/yr dpmDE ? Proper motion in DE difference Cluster - Cepheid 192-199 F8.3 mas/yr e_dpmDE ? Combined error budget on dpmDE 201-203 A3 --- r_pm0 Reference used for Cluster proper motion (1) 205-209 A5 --- r_pm1 Reference used for Cepheid proper motion (1) 211-218 F8.3 [Sun] d[Fe/H] ? [Fe/H] difference Cluster - Cepheid 220-227 F8.3 [Sun] e_d[Fe/H] ? combined error budget on d[Fe/H] 229-231 A3 --- r_[Fe/H]0 Reference used for Cluster [Fe/H] (1) 233-236 A4 --- r_[Fe/H]1 Reference used for Cepheid [Fe/H] (1) 238-245 F8.3 [yr] dAge ? log10(Age) difference Cluster - Cepheid 247-254 F8.3 [yr] e_dAge ? Combined error budget on dAge 256-258 A3 --- r_dAge0 Reference used for Cluster age (1) 260-261 A2 --- r_dAge1 Reference used for Cepheid age (1) -------------------------------------------------------------------------------- Note (1): For details about references, see file refs.dat -------------------------------------------------------------------------------- Byte-by-byte Description of file: clusters.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 17 A17 --- Cluster Cluster name 19- 20 I2 h RAh Right ascension (J2000.0) 22- 23 I2 min RAm Right ascension (J2000.0) 25- 26 I2 s RAs Right ascension (J2000.0) 28 A1 --- DE- Declination sign (J2000.0) 29- 30 I2 deg DEd Declination (J2000.0) 32- 33 I2 arcmin DEm Declination (J2000.0) 35- 36 I2 arcsec DEs Declination (J2000.0) 38- 43 F6.2 arcmin rcore Core radius 45- 51 F7.2 arcmin rlim Limiting radius 52 A1 --- Note [*] Asterisk indicates radius estimated from apparent diameter -------------------------------------------------------------------------------- Byte-by-byte Description of file: cepheids.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 26 A26 --- Cepheid Cepheid name 28- 29 I2 h RAh Right ascension (J2000.0) 31- 32 I2 min RAm Right ascension (J2000.0) 34- 35 I2 s RAs Right ascension (J2000.0) 37 A1 --- DE- Declination sign (J2000.0) 38- 39 I2 deg DEd Declination (J2000.0) 41- 42 I2 arcmin DEm Declination (J2000.0) 44- 45 I2 arcsec DEs Declination (J2000.0) 47- 54 F8.4 d Per ? Pulsation period 56- 60 F5.2 mag Vmag ? Average V-band magnitude -------------------------------------------------------------------------------- Byte-by-byte Description of file: refs.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Ref Reference code 7-157 A151 --- Com Comments -------------------------------------------------------------------------------- Acknowledgements: Richard I. Anderson, richard.anderson(at)unige.ch ================================================================================ (End) Richard I. Anderson [Geneva Obs.], Patricia Vannier [CDS] 01-Jul-2013