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Title

K dwarfs and the chemical evolution of the solar cylinder

Author(s)

Kotoneva, Eira;  Flynn, Chris;  Chiappini, Cristina;  Matteucci, Francesca

Abstract

K-dwarfs have life-times older than the present age of the Galactic disc, and are thus ideal stars to investigate the disc's chemical evolution. We have developed several photometric metallicity indicators for K dwarfs, based an a sample of accurate spectroscopic metallicities for 34 disc and halo G and K dwarfs. The photometric metallicities lead us to develop a metallicity index for K dwarfs based only on their position in the colour absolute-magnitude diagram. Metallicities have been determined for 431 single K dwarfs drawn from the Hipparcos catalog, selecting the stars by absolute magnitude and removing multiple systems. The sample is essentially a complete reckoning of the metal content in nearby K dwarfs. We use stellar isochrones to mark the stars by mass, and select a subset of 220 of the stars which is complete in a narrow mass interval. We fit the data with a model of the chemical evolution of the Solar cylinder. We find that only a modest cosmic scatter is required to fit our age metallicity relation. The model assumes two main infall episodes for the formation of the halo-thick disc and thin disc respectively. The new data confirms that the solar neighbourhood formed on a long timescale of order 7 Gyr.

Publication type

Journal article

Research centre

Swinburne University of Technology. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 336, no. 3 (Nov 2002), pp. 879-891

Publication year

2002

FOR Code(s)

0201 Astronomical and Space Sciences

Publisher

Blackwell

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1046/j.1365-8711.2002.05825.x

Copyright

Copyright © 2002 Royal Astronomical Society. The accepted manuscript is reproduced in accordance with the copyright policy of the publisher. The definitive publication is available at www.interscience.wiley.com.

Full text

Peer reviewed