A revision of the solar neighbourhood metallicity distribution

Authors
Citation
M. Haywood, A revision of the solar neighbourhood metallicity distribution, M NOT R AST, 325(4), 2001, pp. 1365-1382
Citations number
75
Categorie Soggetti
Space Sciences
Journal title
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
ISSN journal
00358711 → ACNP
Volume
325
Issue
4
Year of publication
2001
Pages
1365 - 1382
Database
ISI
SICI code
0035-8711(20010821)325:4<1365:AROTSN>2.0.ZU;2-F
Abstract
We present a revised metallicity distribution of dwarfs in the solar neighb ourhood. This distribution is centred on solar metallicity. We show that pr evious metallicity distributions, selected on the basis of spectral type, a re biased against stars with solar metallicity or higher. A selection of G- dwarf stars is inherently biased against metal-rich stars and is not repres entative of the solar neighbourhood metallicity distribution. Using a sampl e selected on colour, we obtain a distribution where approximately half the stars in the solar neighbourhood have metallicities higher than [Fe/H] = 0 . The percentage of mid-metal-poor stars ([Fe/H] < -0.5) is approximately 4 per cent, in agreement with present estimates of the thick disc. In order to have a metallicity distribution comparable to chemical evolutio n model predictions, we convert the star fraction to mass fraction, and sho w that another bias against metal-rich stars affects dwarf metallicity dist ributions, due to the colour (or spectral type) limits of the samples. Reco nsidering the corrections resulting from the increasing thickness of the st ellar disc with age, we show that the simple closed-box model with no insta ntaneous recycling approximation gives a reasonable fit to the observed dis tribution. Comparisons with the age-metallicity relation and abundance rati os suggest that the simple closed-box model may be a viable model of the ch emical evolution of the Galaxy at solar radius.