相关论文: Metallicity estimates of Galactic Cepheids based o…
We describe the methodology required for estimation of photometric estimates of metallicity based on the SDSS gri passbands, which can be used to probe the properties of main-sequence stars beyond ~ 10 kpc, complementing studies of nearby…
Based on a carefully constructed sample of dwarf stars, a new optical-near infrared photometric calibration to estimate the metallicity of late-type K and early-to-mid-type M dwarfs is presented. The calibration sample has two parts; the…
The mean metallicity of the Milky Way thin disc in the solar neighbourhood is still a matter of debate, and has recently been subject to upward revision (Haywood, 2001). Our star sample was drawn from a set of solar neighbourhood dwarfs…
The MEarth Project is a photometric survey systematically searching the smallest stars nearest to the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late…
In a series of three papers, we investigate the current status of published metallicities for open clusters that were derived from a variety of photometric and spectroscopic methods. The current article focuses on spectroscopic methods. The…
We present a re-analysis of the Geneva-Copenhagen survey, which benefits from the infrared flux method to improve the accuracy of the derived stellar effective temperatures and uses the latter to build a consistent and improved metallicity…
Analysis of cluster and field star uvby data demonstrates the existence of a previously undetected discrepancy in a widely used photometric metallicity calibration for G dwarfs. The discrepancy is systematic and strongly color-dependent,…
We develop a method to estimate photometric metallicities by simultaneously fitting the dereddened colors u-g, g-r, r-i and i-z from the SDSS with those predicted by the metallicity-dependent stellar loci. The method is tested with a…
Classical Cepheids (DCEPs) play a fundamental role in the calibration of the extra-galactic distance ladder which eventually leads to the determination of the Hubble constant($H_0$) thanks to the period-luminosity ($PL$) and…
In this study, a new semi-empirical calibration is proposed between ultraviolet emission lines (\ion{C}{iii}]$\lambda1909$, \ion{C}{iv}$\lambda1549$, \ion{He}{ii}]$\lambda1640$) of type~2 AGNs and their metallicity ($Z$). This calibration…
The C-MetaLL project has provided homogeneous spectroscopic abundances of 290 Classical Cepheids (DCEPs) for which we have the intensity-averaged magnitudes in multiple optical and near-infrared (NIR) bands, periods, pulsation modes, and…
Classical Cepheids (DCEPs) are the first fundamental step in the calibration of the cosmological distance ladder. Furthermore, they represent powerful tracers in the context of Galactic studies. We have collected high-resolution…
The upcoming generation of optical spectrographs on four meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide high-quality spectra for…
Metallicity is one of four free parameters typically considered when fitting isochrones to the cluster sequence. Unfortunately, this parameter is often ignored or assumed to be solar in most papers. Hence an unknown bias is introduced in…
The metallicity dependence of the primary indices of the uvby photometric system for cooler dwarfs (Teff ~ 6500 K to 5000K) is investigated. The data base for the analysis is composed of the overlap between a composite catalog of selected,…
Milky Way Cepheid variables with accurate {\it Hubble Space Telescope} photometry have been established as standards for primary calibration of the cosmic distance ladder to achieve a percent-level determination of the Hubble constant…
We apply the stellar locus method to synthetic $(BP-RP)_{XPSP}$ and $(BP-G)_{XPSP}$ colors derived from corrected Gaia BP/RP (XP) spectra to obtain precise estimates of metallicity for about 100 million stars in the Milky Way (34 million…
We used the data of 701 stars covering the colour index interval 0.32<B-V<=1.16, with metallicities -1.76<=[Fe/H]<=+0.40 dex, which were taken from PASTEL catalogue and estimated metallicity dependent guillotine factors which provide a more…
As the field of exoplanetary astronomy has matured, demand has grown for precise stellar abundances to probe subtle correlations between stellar compositions and planetary demographics. However, drawing population-level conclusions from the…
We analyse a sample of 236 Cepheids from the Hipparcos catalog, using the method of ``reduced parallaxes'' in V, I, K and the reddening-free ``Wesenheit-index''. We compare our sample to those considered by Feast & Catchpole (1997) and…