Toward a renewed Galactic Cepheid distance scale from Gaia and optical interferometry

Pierre Kervella, Antoine Mérand, Alexandre Gallenne, Boris Trahin, Nicolas Nardetto, Richard I. Anderson, Joanne Breitfelder, Laszlo Szabados, Howard E. Bond, Simon Borgniet, Wolfgang Gieren, Grzegorz Pietrzyński

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Through an innovative combination of multiple observing techniques and modeling, we are assembling a comprehensive understanding of the pulsation and close environment of Cepheids. We developed the SPIPS modeling tool that combines all observables (radial velocimetry, photometry, angular diameters from interferometry) to derive the relevant physical parameters of the star (effective temperature, infrared excess, reddening, ⋯) and the ratio of the distance and the projection factor d/p. We present the application of SPIPS to the long-period Cepheid RS Pup, for which we derive p = 1.25±0.06. The addition of this massive Cepheid consolidates the existing sample of p-factor measurements towards long-period pulsators. This allows us to conclude that p is constant or mildly variable around p = 1.29±0.04 (±3%) as a function of the pulsation period. The forthcoming Gaia DR2 will provide a considerable improvement in quantity and accuracy of the trigonometric parallaxes of Cepheids. From this sample, the SPIPS modeling tool will enable a robust calibration of the Cepheid distance scale.

Original languageEnglish (US)
Title of host publicationWide-Field Variability Surveys
Subtitle of host publicationA 21st Century Perspective - 22nd Los Alamos Stellar Pulsation - Conference Series Meeting
EditorsWolfgang Gieren, Marcio Catelan, Wolfgang Gieren, Marcio Catelan
PublisherEDP Sciences
ISBN (Electronic)9782759890248
StatePublished - Sep 8 2017
Event22nd Los Alamos Stellar Pulsation Conference Series Meeting 2016 - San Pedro de Atacama, Chile
Duration: Nov 28 2016Dec 2 2016

Publication series

NameEPJ Web of Conferences
ISSN (Print)2101-6275
ISSN (Electronic)2100-014X


Other22nd Los Alamos Stellar Pulsation Conference Series Meeting 2016
CitySan Pedro de Atacama

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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