2007/02/05 by D. Harold McNamara, D. H. McNamara, Gisella Clementini +3 · 2 citations
Physics and Astronomy · #Apparent magnitude #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Cepheid variable #Cosmic distance ladder #Distance modulus #Galaxies: Formation, Evolution, Phenomena #Galaxy #Globular cluster #Large Magellanic Cloud #Luminosity #Physics #RR Lyrae variable #Stars #Stellar, planetary, and galactic studies #Variable star #astro-ph
paper · pdf · doi:10.1086/513717
published as Astron.J.133:2752-2763,2007 · Accepted for publication on AJ
arxiv created 2007/02/05 · openalex publication_date 2007/05/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present results from a well-studied δ Scuti star discovered in the Large Magellanic Cloud (LMC). The absolute magnitude of the variable was determined from the period-luminosity ( P - L ) relation for Galactic δ Scuti stars and from theoretical modeling of the observed B , V , I light curves with nonlinear pulsation models. The two methods give distance moduli for the LMC of 18.46 ± 0.19 and 18.48 ± 0.15, respectively, for a consistent value of the stellar reddening of E ( B - V ) = 0.08 ± 0.02. We have also analyzed 24 δ Scuti candidates discovered in the OGLE II survey of the LMC, and seven variables identified in the open cluster LW 55 and in the galaxy disk by Kaluzny and coworkers . We find that the LMC δ Scuti stars define a P - L relation whose slope is very similar to that defined by the Galactic δ Scuti variables, and yield a distance modulus for the LMC of 18.50 ± 0.22 mag. We compare the results obtained from the δ Scuti variables with those derived from the LMC RR Lyrae stars and Cepheids. The corresponding distance moduli are as follows: δ Scuti stars, 18.48 ± 0.02 mag (standard deviation of the weighted average of the three above solutions); RR Lyrae stars, 18.49 ± 0.06 mag; and Cepheids, 18.53 ± 0.02 mag. We have assumed an average color excess of E ( B - V ) = 0.08 ± 0.02 mag for both δ Scuti stars and Cepheids. Within the observational uncertainties, the three groups of pulsating stars yield very similar distance moduli. These moduli are all consistent with the "long" astronomical distance scale for the Large Magellanic Cloud.