WIYN Open Cluster Study. XIX. Main Sequence Fitting Distances to Open Clusters Using V-K Color-Magnitude Diagrams

Abstract

We have combined existing optical magnitudes for stars in seven open clusters and 54 field stars with the corresponding JHKs photometry from the Two Micron All Sky Survey (2MASS). Combining optical with near-IR photometry broadens the color baseline minimizing the influence of photometric errors and allows better discrimination between cluster stars and contaminating foreground and background populations. The open clusters in this study include NGC 2516, M35, M34, NGC 3532, M37, M67, and NGC 188. The field stars we are using possess high quality Hipparcos parallaxes and well-determined metal abundances allowing us to empirically determine the dependence of (V-K) color on metal abundance in the range -0.45<=[Fe/H]<=+0.35. Using this relation along with the parallaxes of the field stars, we are able to construct an unevolved main sequence in the [Mv,(V-K)o] diagram for a specific abundance. These diagrams are then used to fit to the cluster main sequences in the [V,V-K] color-magnitude diagram in order to estimate a distance for each open cluster. We find that the resultant distances are within the range of distances found in the literature via the main sequence fitting technique. It is hoped that this will spur an expansion of the current (limited) database of star clusters with high quality (V-K) photometry down to the unevolved main sequence.

arXiv comment17 pages, 7 figures, to appear in The Astronomical Journal - February 2004

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Cited by in corpus (18)

• Probing The Lower Mass Limit for Supernova Progenitors and the High-Mass End of the Initial-Final Mass Relation from White Dwarfs in the Open Cluster M35 (NGC 2168)
• The Yale-Potsdam Stellar Isochrones (YaPSI)
• The open cluster initial-final mass relationship and the high-mass tail of the white dwarf distribution
• Deep 2MASS Photometry of M67 and Calibration of the Main Sequence J-Ks Color Difference as an Age Indicator
• The Monitor project: Searching for occultations in young open clusters
• Deep MMT Transit Survey of the Open Cluster M37 I: Observations and Cluster Parameters
• Primordial Binary Evolution and Blue Stragglers
• From Young and Hot to Old and Cold: Comparing White Dwarf Cooling Theory to Main Sequence Stellar Evolution in Open Clusters
• A Search for sub-km KBOs with the Method of Serendipitous Stellar Occultations
• Close binary stars in the solar-age Galactic open cluster M67
• The distance to the Pleiades: Main sequence fitting in the near infrared
• The White Dwarf Population in NGC 1039 (M34) and the White Dwarf Initial-Final Mass Relation
• Deep, Wide-field CCD Photometry for the Open Cluster NGC3532
• Blue Straggler Stars in Galactic Open Clusters and the Simple Stellar Population Model
• Initial-Final Mass Relation for 3 to 4 M${}_{\odot }$ Progenitors of White Dwarfs from the Single Cluster NGC 2099
• HI Selected Galaxies in the Sloan Digital Sky Survey II: The Colors of Gas-Rich Galaxies
• Astro-photometric study of M37 with Gaia and wide-field ugi-imaging
• Absolute Magnitude Calibration for Dwarfs Based on the Colour-Magnitude Diagrams of Galactic Clusters