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.
<Mon. Not. R. Astron. Soc. 434, 2238 (2013)>
=2013MNRAS.434.2238A 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:
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FileName Lrecl Records Explanations
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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
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See also:
J/PAZh/25/689 : Young open clusters kinematical parameters (Rastorguev+, 1999)
Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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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)
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Note (1): For details about references, see file refs.dat
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Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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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
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Byte-by-byte Description of file: cepheids.dat
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Bytes Format Units Label Explanations
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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
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ref Reference code
7-157 A151 --- Com Comments
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Acknowledgements:
Richard I. Anderson, richard.anderson(at)unige.ch
(End) Richard I. Anderson [Geneva Obs.], Patricia Vannier [CDS] 01-Jul-2013