A δ Scuti Distance to the Large Magellanic Cloud

Abstract

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.

Locations

• The Astronomical Journal - View - PDF
• DataCite API - View