Observational studies of Cepheids. II - BVRI photometry of 112 Cepheids

Moffett, T. J.; Barnes, Thomas G.

doi:10.1086/190960

Cited by 118 publications

(95 citation statements)

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“…5. This comparison star has been used before in a study of Cepheids (Moffet & Barnes 1984), and we found no variations. No check stars were observed.…”

Section: Observations and Reductionssupporting

confidence: 55%

On the variability of the visual binary WR 86

Paardekooper

Veen

Genderen

et al. 2002

A&A

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“…5. This comparison star has been used before in a study of Cepheids (Moffet & Barnes 1984), and we found no variations. No check stars were observed.…”

Section: Observations and Reductionssupporting

confidence: 55%

On the variability of the visual binary WR 86

Paardekooper

Veen

Genderen

et al. 2002

A&A

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“…The associated uncertainty is estimated to ±0.03 mag per measurement (Winters et al 2011). We supplemented the new SMARTS photometric measurements with archival visible light photometry from Moffett & Barnes (1984), Berdnikov (2008), andPel (1976). In order to improve the coverage of the recent epochs, we also added a set of accurate photoelectric measurements retrieved from the P. Kervella et al: Projection factor of the long-period Cepheid RS Pup Table 1.…”

Section: Photometrymentioning

confidence: 99%

Observational calibration of the projection factor of Cepheids

Kervella

Trahin

Bond

et al. 2017

A&A

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The projection factor (p-factor) is an essential component of the classical Baade-Wesselink (BW) technique, which is commonly used to determine the distances to pulsating stars. It is a multiplicative parameter used to convert radial velocities into pulsational velocities. As the BW distances are linearly proportional to the p-factor, its accurate calibration for Cepheids is of critical importance for the reliability of their distance scale. We focus on the observational determination of the p-factor of the long-period Cepheid RS Pup (P = 41.5 days). This star is particularly important as this is one of the brightest Cepheids in the Galaxy and an analog of the Cepheids used to determine extragalactic distances. An accurate distance of 1910 ± 80 pc (±4.2%) has recently been determined for RS Pup using the light echoes propagating in its circumstellar nebula. We combine this distance with new VLTI/PIONIER interferometric angular diameters, photometry, and radial velocities to derive the p-factor of RS Pup using the code Spectro-Photo-Interferometry of Pulsating Stars (SPIPS). We obtain p = 1.250 ± 0.064 (±5.1%), defined for cross-correlation radial velocities. Together with measurements from the literature, the p-factor of RS Pup confirms the good agreement of a constant p = 1.293 ± 0.039 (±3.0%) model with the observations. We conclude that the p-factor of Cepheids is constant or mildly variable over a broad range of periods (3.7 to 41.5 days).

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“…We took the photometry from Moffett & Barnes (1984), Barnes et al (1997), Kiss (1998), Berdnikov (2008) and Engle et al (2014). We also added photometric observations from Tycho and H from van Leeuwen et al (1997) andESA (1997).…”

Section: δ Cepmentioning

confidence: 99%

Cepheid distances from the SpectroPhoto-Interferometry of Pulsating Stars (SPIPS)

Mérand

Kervella

Breitfelder

et al. 2015

A&A

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Context. The parallax of pulsation, and its implementations such as the Baade-Wesselink method and the infrared surface brightness technique, is an elegant method to determine distances of pulsating stars in a quasi-geometrical way. However, these classical implementations in general only use a subset of the available observational data. Aims. Freedman & Madore (2010, ApJ, 719, 335) suggested a more physical approach in the implementation of the parallax of pulsation in order to treat all available data. We present a global and model-based parallax-of-pulsation method that enables including any type of observational data in a consistent model fit, the SpectroPhoto-Interferometric modeling of Pulsating Stars (SPIPS). Methods. We implemented a simple model consisting of a pulsating sphere with a varying effective temperature and a combination of atmospheric model grids to globally fit radial velocities, spectroscopic data, and interferometric angular diameters. We also parametrized (and adjusted) the reddening and the contribution of the circumstellar envelopes in the near-infrared photometric and interferometric measurements. Results. We show the successful application of the method to two stars: δ Cep and η Aql. The agreement of all data fitted by a single model confirms the validity of the method. Derived parameters are compatible with publish values, but with a higher level of confidence. Conclusions. The SPIPS algorithm combines all the available observables (radial velocimetry, interferometry, and photometry) to estimate the physical parameters of the star (ratio distance/p-factor, T eff , presence of infrared excess, color excess, etc). The statistical precision is improved (compared to other methods) thanks to the large number of data taken into account, the accuracy is improved by using consistent physical modeling and the reliability of the derived parameters is strengthened thanks to the redundancy in the data.

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Observational studies of Cepheids. II - BVRI photometry of 112 Cepheids

Cited by 118 publications

References 0 publications

On the variability of the visual binary WR 86

On the variability of the visual binary WR 86

Observational calibration of the projection factor of Cepheids

Cepheid distances from the SpectroPhoto-Interferometry of Pulsating Stars (SPIPS)

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