Details

Autor(en) / Beteiligte

• Breitfelder, J
• Merand, A
• Kervella, P
• Gallenne, A
• Szabados, L
• Anderson, R I
• Le Bouquin, J-B

Titel

Observational calibration of the projection factor of Cepheids: II. Application to nine Cepheids with HST/FGS parallax measurements

Ist Teil von

• Astronomy and astrophysics (Berlin), 2016-03, Vol.587, p.A117

Erscheinungsjahr

2016

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Context. The distance to pulsating stars is classically estimated using the parallax-of-pulsation (PoP) method, which combines spectroscopic radial velocity (RV) measurements and angular diameter (AD) estimates to derive the distance of the star. A particularly important application of this method is the determination of Cepheid distances in view of the calibration of their distance scale. We aim to measure empirically the value of the p-factors of a homogeneous sample of nine bright Galactic Cepheids for which trigonometric parallaxes were measured with the Hubble Space Telescope (HST) Fine Guidance Sensor. We use the SPIPS algorithm, a robust implementation of the PoP method that combines photometry, interferometry, and radial velocity measurements in a global modeling of the pulsation of the star. We obtained new interferometric angular diameter measurements using the PIONIER instrument at the Very Large Telescope Interferometer (VLTI), completed by data from the literature. The values of the p-factors that we obtain are consistently close to p = 1.324 [+ or -] 0.024.