Free Access
Volume 550, February 2013
Article Number A70
Number of page(s) 25
Section Galactic structure, stellar clusters and populations
Published online 29 January 2013

Online material

Table 1

Sources of V-, K-band and RV data for the Galactic Cepheids.

Table 2

Sources of V-, K-band and RV data for the MC Cepheids.

Table 3

New radial velocity data.

Table 4

Published [Fe/H] values for the Galactic Cepheids.

Table 5

Published [Fe/H] values for the MC Cepheids.

Table 6

Stars with parallaxes and/or interferometrically determined angular diameters.

Table 10

Distances, radii, and absolute magnitudes from the BW analysis.

Appendix A: Cluster distances

It is not our intention to give a review on the distances to Galactic clusters containing Cepheids. Recent compilations of distances can be found in Turner (2010) and Tammann et al. (2003). The latter is based on Feast (1999), which is an update of Feast & Walker (1987), with detailed remarks in Walker (1987b).

However, when comparing cluster distances quoted in the literature to the BW distances obtained here and checking the literature in more detail, it was obvious that not all distances were given on the same distance scale. In addition, some results obtained since Turner (2010) can be included in the analysis.

Traditionally, the distances to clusters are based on Zero Age Main Sequence (ZAMS) fitting using BV data and a reference ZAMS, which is very often that of Turner (1976, 1979a). It is tied to a DM to the Pleiades of 5.56.

Recently, Turner, Majaess and co-workers used ZAMS fitting with 2MASS JHK data to derive distances to Cepheids containing clusters. The procedure is outlined in Majaess et al. (2011), and the distances to nine benchmark open clusters thathave HST and revised Hipparcos-based distances (van Leeuwen 2009) determined. There is the well-known disagreement for the Pleiades, but the infrared ZAMS fitting distances to the other clusters, and the comparison to the Hyades and Pleiades that have HST-based parallaxes is excellent. The 2MASS-based ZAMS fitting is therefore tied to a DM of 5.65 for the Pleiades, which is thus different from that implied when using the Turner ZAMS in the optical.

In Table A.1, the adopted cluster-based DM are listed for the Cepheids in the sample. Infrared ZAMS fitting is preferred over earlier work in the optical. Where appropriate, the older work is scaled to the adopted Pleiades distance. A few Cepheids in clusters that are in our sample, but where the association is uncertain or the DM in the literature are very discrepant, have not been considered: KQ Sco, GY Sge, T Mon, SV Vul (see Hoyle et al. 2003)

Table A.1

Distances to cluster containing Cepheids.

© ESO, 2013

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