AAS 204th Meeting, June 2004
Session 7 A Walk Through the HR Diagram
Poster, Monday, May 31, 2004, 9:20am-6:30pm, Ballroom

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[7.16] The Hyades: Photometric Stellar Temperatures and an Updated Mean Metallicity

B. J. Taylor, M. D. Joner (Brigham Young University)

Published high-dispersion metallicities for the Hyades have not been derived on a uniform temperature scale. If the metallicities are to be interpreted correctly, they must therefore be corrected to a scale based on stellar angular diameters. Such an analysis has been performed by Taylor (1998, PASP, 110, 708) and is updated in this paper.

The results of the original and updated analyses do not sustain a widespread impression that the mean Hyades value of [Fe/H] is about +0.13 dex. A result of this sort given by Perryman et al. (1998, A&A, 331, 81) is already known to be an artifact of incomplete data sampling and data correction (see Appendix B of Taylor 2000, A&A, 362, 553). It is found here that a similar result by Paulson et al. (2003, AJ, 125, 3185) is based on a spectroscopic temperature scale that is offset from the solar temperature by about 90 K.

A preliminary revision of the Paulson et al. data yields an upper limit of +0.107 ±0.006 dex for the mean Hyades value of [Fe/H]. Other data yield consistent mean metallicities of +0.097 ±0.009 dex for dwarfs and +0.108 ±0.022 dex for giants. The weighted average of the second and third data is +0.099 ±0.008 dex. Pending further work, this mean value is recommended for use in Hyades analyses.

As an aid to further spectroscopic studies, a catalog of photometric temperatures is given for 134 Hyades F2--K7 dwarfs. These temperatures are based on Strömgren, Cousins, Kron, H-alpha, and B-V photometry, and are on a scale based on stellar angular diameters.

This research has been supported by the BYU College of Physical and Mathematical Sciences.

The author(s) of this abstract have provided an email address for comments about the abstract: taylorb@byu.edu

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