The N2K Consortium. V. Identifying Very Metal-rich Stars with Low-Resolution Spectra: Finding Planet-Search Targets
Abstract
We present empirical calibrations that provide estimates of stellar metallicity, effective temperature, and surface gravity as a function of Lick IDS indices. These calibrations have been derived from a training set of 261 stars for which (1) high-precision measurements of [Fe/H], Teff, and logg have been made using spectral-synthesis analysis of HIRES spectra, and (2) Lick indices have also been measured. Estimation of atmospheric parameters with low-resolution spectroscopy rather than photometry has the advantage of producing a highly accurate metallicity calibration, and requires only one observation per star. Our calibrations have identified a number of bright (V<9) metal-rich stars that are now being screened for hot-Jupiter-type planets. Using the Yonsei-Yale stellar models, we show that the calibrations provide distance estimates accurate to ~20% for nearby stars. We have also investigated the possibility of constructing a ``planeticity'' calibration to predict the presence of planets based on stellar abundance ratios but find no evidence that a convincing relation of this type can be established. High metallicity remains the best single indicator that a given star is likely to harbor extrasolar planets.
- Publication:
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The Astrophysical Journal
- Pub Date:
- February 2006
- DOI:
- 10.1086/498565
- arXiv:
- arXiv:astro-ph/0510150
- Bibcode:
- 2006ApJ...637.1102R
- Keywords:
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- Methods: Statistical;
- Stars: Planetary Systems;
- Stars: Abundances;
- Astrophysics
- E-Print:
- Accepted for publication in the Astrophysical Journal