2000/02/16 by M. A. T. Groenewegen, Groenewegen, M. A. T., R. D. Oudmaijer +2
Earth and Planetary Sciences · Physics and Astronomy · #Astronomical and nuclear sciences #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Geophysics and Gravity Measurements #History and Developments in Astronomy #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0002325
Accepted by Astronomy and Astrophysics
arxiv created 2000/02/16 · openalex publication_date 2000/02/16 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
We analyse a sample of 236 Cepheids from the Hipparcos catalog, using the\nmethod of ``reduced parallaxes'' in V, I, K and the reddening-free\n``Wesenheit-index''. We compare our sample to those considered by Feast &\nCatchpole (1997) and Lanoix et al. (1999).\n We stress the importance of two systematic effects which influence the\ndistance to the LMC: the slopes of the Galactic PL-relations and metallicity\ncorrections. In order to assess the influence of these various effects, we\npresent 27 distance moduli (DM) to the LMC, based on three different colours\n(V,I,K), three different slopes, and three different metallicity corrections.\n The DM to the LMC based on the parallax data can be summarised as follows.\nBased on the PL-relation in V and I, and the Wesenheit-index, the DM is 18.60\n\± 0.11 (\± 0.08 slope)(+0.08-0.15 metallicity), which is our current\nbest estimate.\n Based on the PL-relation in K the DM is 18.52 \± 0.18 (\± 0.03 slope) (\±\n0.06 metallicity)(+0.10-0 sampling bias).\n The random error is mostly due to the given accuracy of the Hipparcos\nparallaxes and the number of Cepheids in the respective samples. The terms\nbetween parentheses indicate the possible systematic uncertainties due to the\nslope of the Galactic PL-relations, the metallicity corrections, and in the\nK-band, due to the limited number of stars. Recent work by Sandage et al.\n(1999) indicates that the effect of metallicity towards shorter distances may\nbe smaller in V and I than indicated here.\n