2010A&A...518A..11P


Query : 2010A&A...518A..11P

2010A&A...518A..11P - Astronomy and Astrophysics, volume 518, A11-11 (2010/7-2)

New Baade-Wesselink distances and radii for four metal-rich galactic cepheids.

PEDICELLI S., LEMASLE B., GROENEWEGEN M., ROMANIELLO M., BONO G., LANEY C.D., FRANCOIS P., BUONANNO R., CAPUTO F., LUB J., PEL J.W., PRIMAS F. and PRITCHARD J.

Abstract (from CDS):

We provide accurate estimates of distances, radii, and iron abundances of 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. 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 calibrations of both the IR surface brightness relation and the projection factor. We also provide accurate measurements of the iron abundance of the target Cepheids. Current distance estimates agree to within one σ with similar distances based on either empirical or theoretical NIR Period-Luminosity (P-L) relations. However, the uncertainties in the Baade-Wesselink distances are on average a factor of 3-4 smaller than errors affecting other distance determinations. Mean Baade-Wesselink radii also agree at the one σ level with Cepheid radii based either on empirical or theoretical Period-Radius relations. Iron abundances are, within one σ, similar to those determined by Andrievsky and collaborators, thus confirming that the target Cepheids are super metal-rich. We also found that the luminosity amplitudes of classical Cepheids, at odds with RR Lyrae stars, do not exhibit a clear correlation with their metal content. This circumstantial evidence appears to be caused by the Hertzsprung progression and the dependence of the topology of the instability strip on metallicity, evolutionary effects, and binaries.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: distances - stars: variables: Cepheids - Galaxy: disk - stars: oscillations

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 654 2
2 V* V340 Ara cC* 16 45 19.1125726896 -51 20 33.393735924   11.39 10.03     ~ 75 0
3 V* AV Sgr cC* 18 04 48.7861680960 -22 43 56.639297172   13.39 11.49   10.595 ~ 62 0
4 V* VY Sgr cC* 18 12 04.5659242512 -20 42 14.462412336   12.70 11.36     F6 70 0
5 V* UZ Sct cC* 18 31 22.3668789696 -12 55 43.335648156   13.23 10.91   9.195 G0 83 0
6 * del Cep cC* 22 29 10.2626640314 +58 24 54.697613650 4.71 4.35 3.75   3.219 F5Iab:+B7-8 710 0
7 NAME Local Group GrG ~ ~           ~ 7893 0

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2023.01.31-02:18:00

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