Search Publications
The chemical compositions of Galactic disc F and G dwarfs
Lambert, David L.; Allende Prieto, Carlos; Reddy, Bacham E. +1 more
Photospheric abundances are presented for 27 elements from carbon to europium in 181 F and G dwarfs from a differential local thermodynamic equilibrium (LTE) analysis of high-resolution and high signal-to-noise ratio spectra. Stellar effective temperatures (Teff) were adopted from an infrared flux method calibration of Strömgren photome…
Is there really a Lutz-Kelker bias? Reconsidering calibration with trigonometric parallaxes
Smith, Haywood
In the recent literature there are indications of some confusion regarding the Lutz-Kelker bias: whether or not it exists, and if so, what it is and when it should be corrected. Here we carefully reexamine Lutz & Kelker's original work to understand what they actually did, and then look at their later papers and some other works on the subject…
Distances to Cepheid open clusters via optical and K-band imaging
Tanvir, N. R.; Shanks, Tom; Hoyle, Fiona
We investigate the reddening and main-sequence-fitted distances to 11 young, Galactic open clusters that contain Cepheids. Each cluster contains or is associated with at least one Cepheid variable star. Reddening to the clusters is estimated using the U-B:B-V colours of the OB stars and the distance modulus to the cluster is estimated via B-V:V an…
An empirical test of the theoretical population corrections to the red clump absolute magnitude
Salaris, Maurizio; Percival, Susan M.
The mean absolute magnitude of the local red clump (RC), MRCλ, is a very well-determined quantity owing to the availability of accurate Hipparcos parallaxes for several hundred RC stars, potentially allowing it to be used as an accurate extragalactic distance indicator. Theoretical models predict that the RC mean magnitude is…
Three-component Stäckel potentials satisfying recent estimates of Milky Way parameters
Famaey, B.; Dejonghe, H.
We present a set of three-component Stäckel potentials defined by five parameters and designed to model the Milky Way. We review the fundamental constraints that any model of the Milky Way must satisfy, including the most recent ones derived from Hipparcos data, and we study how the parameters of the presented potentials can vary in order to match…
Galactic archaeology: initial mass function and depletion in the `thin disc'
Schröder, K. -P.; Pagel, B. E. J.
We determine the initial mass function (IMF) of the `thin disc' in the range of, approximately, 1.1 to 4 Msolar by means of a direct comparison between synthetic stellar samples [for different matching choices of IMF, star formation rate (SFR) and depletion] and a complete (volume-limited) sample of single stars near the Galactic plane …
On the nature of Collinder 121: insights from the low-mass pre-main sequence
Naylor, Tim; Jeffries, R. D.; Burningham, Ben +1 more
We present a VI photometric catalogue towards the open cluster Cr 121. XMM-Newton and ROSAT data are used to discover a low-mass pre-main sequence (PMS) along this sightline. de Zeeuw et al. have identified Cr 121 as a moving group, using Hipparcos data, at a distance of 592 pc; we reject the scenario that these low-mass PMS stars are associated w…
Some statistical aspects of estimating the local red clump absolute magnitude
Koen, Chris; Lombard, Fred
Various statistical issues regarding estimation of the mean absolute magnitude of the red clump stars, using Hipparcos parallaxes, are discussed. The problem is put in the broader context of estimation of the functional dependence of the absolute magnitude on colour of local giant stars, as derived from Hipparcos observations. The methods used inc…