2000/01/31 by Piotr Popowski · 2 citations
Physics and Astronomy · #Absolute magnitude #Apparent magnitude #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Cepheid variable #Cosmic distance ladder #Distance modulus #Galaxy #Globular cluster #Large Magellanic Cloud #Metallicity #Physics #RR Lyrae variable #Red clump #Redshift #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2001.04046.x
published in Monthly Notices of the Royal Astronomical Society 321(3), 502-506 (Oxford University Press) · version accepted to MNRAS, added discussion about the dependence of the results on theoretical assumptions and observational input, stressed that the derived range of the LMC distance modulus between 18.24 and 18.44 is insensitive to the controversial dereddened I-magnitude of the LMC clump giants
arxiv created 2000/09/26 · openalex publication_date 2001/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
I explore the consequences of making the RR Lyrae and clump giant distance scales consistent in the solar neighbourhood, Galactic bulge and Large Magellanic Cloud (LMC). I employ two major assumptions: (i) that the absolute magnitude—metallicity, MV(RR) — [Fe/H], relation for RR Lyrae stars is universal, and (ii) that absolute I magnitudes of clump giants, MI(RC), in Baade's Window are known (e.g. can be inferred from the local Hipparcos-based calibration or theoretical modelling). A comparison between the solar neighbourhood and Baade's Window sets MV(RR) at [Fe/H]=−1.6 in the range (0.59±0.05,0.70±0.05), somewhat brighter than the statistical parallax solution. More luminous RR Lyrae stars imply younger globular clusters, which would be in better agreement with the conclusions from the currently favoured stellar evolution and cosmological models. A comparison between Baade's Window and the LMC sets MLMCI(RC) in the range (−0.33±0.09, −0.53±0.09). The distance modulus to the LMC is μLMC∈(18.24±0.08,18.44±0.07). UnlikeMLMCI(RC), this range in μLMC does not depend on the adopted value of the dereddened LMC clump magnitude, ILMC0(RC). I argue that the currently available information is insufficient to select the correct distance scale with high confidence.