The Cepheid Period-Luminosity Relation from Independent Distances of 100 Galactic Variables

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

doi:10.1086/173377

Cited by 64 publications

(73 citation statements)

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“…Moreover, he found that a strong period dependence of the p-factor (p ∼ −0.15 · log P, Gieren et al (2005)), could also be ruled out. However, a moderate period dependence (p ∼ −0.03 · log P) as suggested either by Gieren et al (1993Gieren et al ( , 1997Gieren et al ( , 1998; Barnes et al (2003); Storm et al (2004), or more recently by Nardetto et al (2009) (p ∼ −0.08 · log P) is still consistent with currently available data (G07).…”

Section: Introductionsupporting

confidence: 83%

New Baade-Wesselink distances and radii for four metal-rich Galactic Cepheids

Pedicelli

Lemasle

Groenewegen

et al. 2010

A&A

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Aims. We provided accurate estimates of distances, radii and iron abundances for four metal-rich Cepheids, namely V340 Ara, UZ Sct, AV Sgr and VY Sgr. The main aim of this investigation is to constrain their pulsation properties and their location across the Galactic inner disk. Methods. We adopted new accurate NIR (J,H,K) light curves and new radial velocity measurements for the target Cepheids to determinate their distances and radii using the Baade-Wesselink technique. In particular, we adopted the most recent calibration of the IR surface brightness relation and of the projection factor. Moreover, we also provided accurate measurements of the iron abundance of the target Cepheids. Results. Current distance estimates agree within one σ with similar distances based either on empirical or on theoretical NIR PeriodLuminosity relations. However, the uncertainties of the Baade-Wesselink distances are on average a factor of 3-4 smaller when compared with errors affecting other distance determinations. Mean Baade-Wesselink radii also agree at one σ level with Cepheid radii based either on empirical or on theoretical Period-Radius relations. Iron abundances are, within one σ, similar to the iron contents provided by Andrievsky and collaborators, thus confirming the super metal-rich nature of the target Cepheids. We also found that the luminosity amplitudes of classical Cepheids, at odds with RR Lyrae stars, do not show a clear correlation with the metal-content. This circumstantial evidence appears to be the consequence of the Hertzsprung progression together with the dependence of the topology of the instability strip on metallicity, evolutionary effects and binaries.

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Section: Introductionsupporting

confidence: 83%

New Baade-Wesselink distances and radii for four metal-rich Galactic Cepheids

Pedicelli

Lemasle

Groenewegen

et al. 2010

A&A

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“…Given the limited accuracy of Hipparcos (∼1 mas), we do not have an explanation for this apparent detection of parallax, in disagreement with our determination. Gieren et al (1993), namely p = 1.39−0.03 log P, which amounts to 1.341 in the case of RS Pup (log P = 1.6174). Fouqué et al (2007) derived a distance of 1830 pc based on the same data, but using a lower projection factor based on a mean relation derived by Nardetto et al (2007), p = 1.366−0.075 log P (cross-correlation method), which leads to 1.245 in the case of RS Pup.…”

Section: Trigonometric Parallaxmentioning

confidence: 93%

The long-period Galactic Cepheid RS Puppis

Kervella¹,

Mérand

Szabados

et al. 2008

A&A

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Context. The bright southern Cepheid RS Pup is surrounded by a circumstellar nebula reflecting the light from the central star. The propagation of the light variations from the Cepheid inside the dusty nebula creates spectacular light echoes that can be observed up to large distances from the star itself. This phenomenon is currently unique in this class of stars. Aims. For this relatively distant star, the trigonometric parallax available from Hipparcos has a low accuracy. A careful observation of the light echoes has the potential to provide a very accurate, geometric distance to RS Pup. Methods. We obtained a series of CCD images of RS Pup with the NTT/EMMI instrument covering the variation period of the star (P = 41.4 d), allowing us to track the progression of the light wavefronts over the nebular features surrounding the star. We measured precisely the phase lag of the photometric variation in several regions of the circumstellar nebula. Results. From our phase lag measurements, we derive a geometric distance of 1992 ± 28 pc to RS Pup. This distance is affected by a total uncertainty of 1.4%, and corresponds to a parallax of π = 0.502 ± 0.007 mas and a distance modulus of µ = 11.50 ± 0.03. Conclusions. The geometric distance we derive is by far the most accurate to a Cepheid, and among the most accurate to any star. RS Pup appears both as somewhat neglected and particularly promising to investigate the mass-loss history of Cepheids. Thanks to its highly accurate distance, it is also bound to become an important luminosity fiducial for the long period part of the period-luminosity diagram.

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“…This allows us to compare our results with the period-luminosity (PL) calibration of Gieren, Barnes & Moffett (1993), who obtained distances to 100 Galactic Cepheids by the same method. Our ultimate goal is to calibrate the zero point of the PL relation to within a few x 0.01 mag, compared to current accuracies of ±0.1 (cf.…”

Section: Introductionmentioning

confidence: 95%

“…Our initial findings are summarised below. We have another four stars in our main programme and several other possible candidates, which should allow us to make a realistic comparison of the two zero-point systems, tied in to the extensive study of field Cepheids by Gieren, Barnes & Moffett (1993 …”

Section: Checking the Zams Calibrationmentioning

confidence: 99%

Independent Distance Determinations to Milky Way Cepheids in Open Clusters: A progress report on four stars

Giere

Matthews

Mermilliod

et al. 1995

International Astronomical Union Colloquium

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Abstract.We have undertaken a programme to calibrate the Cepheid PL relation zero-point by obtaining distances of Cepheids in open clusters and associations via the visual surface brightness technique. Results are now available for four stars (SZ Tau, CF Cas, CV Mon and DL Cas) and others are currently under analysis. Preliminary results suggest the 'ZAMS-fitting' distances to the host clusters are systematically smaller than those we derive from Cepheid surface brightnesses.

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The Cepheid Period-Luminosity Relation from Independent Distances of 100 Galactic Variables

Cited by 64 publications

References 0 publications

New Baade-Wesselink distances and radii for four metal-rich Galactic Cepheids

New Baade-Wesselink distances and radii for four metal-rich Galactic Cepheids

The long-period Galactic Cepheid RS Puppis

Independent Distance Determinations to Milky Way Cepheids in Open Clusters: A progress report on four stars

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