The Distances to Open Clusters from Main-Sequence Fitting. III. Improved Accuracy with Empirically Calibrated Isochrones

By D. An, D. Terndrup, M. Pinsonneault, D. Paulson, R. Hanson, J. Stauffer. 2006

134 citations recorded by the source corpus.

We continue our series of papers on open cluster distances with a critical assessment of the accuracy of main-sequence fitting using isochrones that employ empirical corrections to the color-temperature relations. We use four nearby open clusters with multicolor photometry and accurate metallicities and present a new metallicity for Praesepe ([Fe/H] = +0.11 ± 0.03) from high-resolution spectra. The internal precision of distance estimates is about a factor of 5 better than the case without the color calibrations. After taking into account all major systematic errors, we obtain distances accurate to about 2%-3% when there exists a good metallicity estimate. Metallicities accurate to better than 0.1 dex may be obtained from BVICKs photometry alone. We also derive a helium abundance for the Pleiades of Y = 0.279 ± 0.015, which is equal within the errors to the Sun's initial helium abundance and that of the Hyades. Our best estimates of distances are (m - M)0 = 6.33 ± 0.04, 8.03 ± 0.04, and 9.61 ± 0.03 to Praesepe, NGC 2516, and M67, respectively. Our Pleiades distance at the spectroscopic metallicity, (m - M)0 = 5.66 ± 0.01(internal) ± 0.05(systematic), is in excellent agreement with several geometric distance measurements. We have made calibrated isochrones for -0.3 ≤ [Fe/H] ≤ +0.2 available online.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/23d8385d38765d47f92188b486258e9061ccc187

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Citations in the corpus

THE CASE FOR THE DUAL HALO OF THE MILKY WAY (2011, background): “As was the case for the I08 approach, the effects of binarity are more difficult to quantify, and are not included in this error estimate (see An et al. 2007).”
A PHOTOMETRIC VARIABILITY SURVEY OF FIELD K AND M DWARF STARS WITH HATNet (2009, methodology): “For M35, M37, and the Hyades we use the mass estimates derived from the V, IC–mass relations from the appropriate YREC (An et al. 2007) isochrones for each cluster.”
Parallaxes and proper motions for 20 open clusters as based on the new Hipparcos catalogue (2009, background): “The distance modulus as derived from the new Hipparcos reduction is, at 6.30 ± 0.07 effectively identical to one determined by An et al. (2007) (6.33± 0.04) and fully consistent with the value derived by Percival et al. (2003) (6.24 ± 0.04, using (V − I)C data).”
New constraints on the chemical evolution of the solar neighbourhood and galactic disc(s) - improved astrophysical parameters for the Geneva-Copenhagen Survey (2011, result): “The difference with respect to the Hyades again excellently agrees with that obtained from the spectroscopic comparison of Boesgaard & Friel (1990), after correcting the Pleiades for known non-members (An et al. 2007).”
The Ages of Stars (2007, background): “For some particular well-studied cases, Pinsonneault et al. (2004) and An et al. (2007) have been able to construct empirical isochrones for ZAMS and post-ZAMS OCs, and Mayne et al. (2007) have done so for PMS stars.”
A REVISED EFFECTIVE TEMPERATURE SCALE FOR THE KEPLER INPUT CATALOG (2011, methodology): “The SDSS-based A09 system is constructed to be on the same absolute scale as the An et al. (2007a) system, so a similar level of agreement is expected between the IRFM and the temperatures that we derive from the SDSS filters.”
MOA-2009-BLG-387Lb: a massive planet orbiting an M dwarf (2011, methodology): “Finally, for the relation between M and MH, we consult the library of empirically-calibrated isochrones of An et al. (2007).”