Memorial for Louis H. Fuchs (1915–1991)

Olsen, Edward

doi:10.1111/j.1945-5100.1992.tb01066.x

Cited by 71 publications

(114 citation statements)

References 10 publications

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“…One of the comparison stars, HD195633, is a well known metal-deficient star (e.g. Cayrel de Strobel et al 1997) with uvby photometry obtained by Schuster & Nissen (1988) and Olsen (1993Olsen ( , 1994b. The new results presented in Table 2 agree closely with the previous data.…”

Section: Uvby Light Curvessupporting

confidence: 82%

“…Details on the spectrometer and the (semi)automatic mode of the telescope are given by Olsen (1993Olsen ( , 1994b.…”

Section: Observations and Photometric Reductionmentioning

confidence: 99%

“…To identify late-F to G5 main-sequence stars, we have used a critical compilation of uvbyβ photometry for about 30 000 stars (Olsen 1988(Olsen , 1993(Olsen , 1994a(Olsen , 1994b together with unpublished β photometry (cf. Olsen 1994b).…”

Section: Selection Of Candidatesmentioning

confidence: 99%

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Absolute dimensions of solar-type eclipsing binaries.

Clausen¹,

Helt²,

Olsen³

2001

A&A

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Abstract. We present complete uvby light curves of 9 recently discovered eclipsing binaries having late F, G, and K type components within or near the main-sequence band. They are the first results from a long term program carried out since 1994 at the Strömgren Automatic Telescope at ESO, La Silla. The aim is to provide the accurate absolute dimensions for solar-type stars needed for critical tests of the corresponding theoretical models. A serious dilemma appears to be present in the comparison of predictions from current stellar models with fundamental properties of known 0.7−1.1 M eclipsing binaries (Popper 1997b, Clausen et al. 1999b). Spectroscopic observations of the 9 eclipsing binaries are either available or are being obtained, and detailed analyses of the individual systems will be published in a series of subsequent papers. The light curves were obtained as part of a systematic search for new eclipsing systems among a large sample of (mostly) spectroscopic binaries. Catalogues of the extensive uvby and β photometry from this search will be published separately.Key words. stars: fundamental parameters -stars: binaries: close -stars: binaries: eclipsing -stars: evolutionstars: late type -techniques: photometric IntroductionDetached, double-lined eclipsing binaries are the main source of accurate (1-2%) data on stellar masses and radii. Few well studied systems with solar-type components are available, and accurate masses and radii for late F-K main-sequence stars are thus scarce. Andersen (1991) includes just three stars in the 0.7−1.1 M mass range (the secondary of FL Lyr and both components of HS Aur). Selection effects (small stars of low luminosity) are responsible for rather few eclipsing binaries with late-type main-sequence components being known, and for the domination of short-period systems in the sample. In order to identify more systems, Popper (1996) undertook an impressive spectroscopic survey of known late F-K eclipsing binaries. High-quality spectroscopic orbits of 10 additional main-sequence systems have been established from this project: RT And and CG Cyg (Popper . Light curves exist for some of these binaries, and absolute dimensions for 9 more stars below 1.1 M have been published.Several of the binaries mentioned above belong to the group of short-period (P < 1 day) RS CVn systems. They have rapidly rotating components (synchronized to the orbital period) with often fairly large relative radii r = R/a. Enhanced surface activity (spots) is present, leading to quite distorted light curves and consequently less welldetermined photometric elements. Attempts to fit current stellar models to the available data show systematic differences between models and binaries, which are not yet understood (Popper 1997b;Clausen et al. 1999b).Whereas Popper (1996) searched spectroscopically for main-sequence systems among known eclipsing binaries, we have chosen to conduct a large-scale photometric search for new eclipsing cases among late-type stars known (or suspected) to be binaries. In particula...

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Section: Uvby Light Curvessupporting

confidence: 82%

“…Details on the spectrometer and the (semi)automatic mode of the telescope are given by Olsen (1993Olsen ( , 1994b.…”

Section: Observations and Photometric Reductionmentioning

confidence: 99%

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Absolute dimensions of solar-type eclipsing binaries.

Clausen¹,

Helt²,

Olsen³

2001

A&A

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“…HD 175272, or HIP 92794, is known as an F5 dwarf. Its V magnitude has been derived from Strömgren photometry by Olsen (1994). From medium-resolution stellar spectra, Prugniel & Soubiran (2001) have estimated the effective temperature to +0.06 ± 0.14 1 be about 6500 K and log g = 4.09; these estimates are presented as poor.…”

Section: Introductionmentioning

confidence: 99%

Differential asteroseismic study of seismic twins observed by CoRoT

Ozel

Mosser

Dupret

et al. 2013

A&A

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Context. The CoRoT short asteroseismic runs give us the opportunity to observe a large variety of late-type stars through their solarlike oscillations. We report the observation and modeling of the F5V star HD 175272. Aims. Our aim is to define a method for extracting as much information as possible from a noisy oscillation spectrum. Methods. We followed a differential approach that consists of using a well-known star as a reference to characterize another star. We used classical tools such as the envelope autocorrelation function to derive the global seismic parameters of the star. We compared HD 175272 with HD 181420 through a linear approach, because they appear to be asteroseismic twins. Results. The comparison with the reference star enables us to substantially enhance the scientific output for HD 175272. First, we determined its global characteristics through a detailed seismic analysis of HD 181420. Second, with our differential approach, we measured the difference of mass, radius and age between HD 175272 and HD 181420. Conclusions. We have developed a general method able to derive asteroseismic constraints on a star even in case of low-quality data. This method can be applied to stars with interesting properties but low signal-to-noise ratio oscillation spectrum, such as stars hosting an exoplanet or members of a binary system.

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“…The zero point for each calibration equation applied to Tombaugh 1 was anchored by observations of eight field star standards obtained on 2010 December 7. Standard values were obtained from the catalogs of Olsen (1983Olsen ( , 1993Olsen ( , 1994 for uvby, from Hauck & Mermilliod (1998) for Hβ values, and from Twarog & Anthony-Twarog (1995) for hk index values for the field star standards. Table 2 summarizes the calibration equations' slopes and color terms.…”

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confidence: 99%

PROPERTIES OF THE OPEN CLUSTER TOMBAUGH 1 FROM HIGH-RESOLUTION SPECTROSCOPY AND uvbyCaHβ PHOTOMETRY*

Silva

Carraro²,

Anthony-Twarog

et al. 2015

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Open clusters can be the key to deepening our knowledge on various issues involving the structure and evolution of the Galactic disk and details of stellar evolution because a cluster's properties are applicable to all its members. However, the number of open clusters with detailed analysis from high-resolution spectroscopy or precision photometry imposes severe limitations on studies of these objects. To expand the number of open clusters with well-defined chemical abundances and fundamental parameters, we investigate the poorly studied, anticenter open cluster Tombaugh 1. Using precision uvbyCaHβ photometry and high-resolution spectroscopy, we derive the cluster's reddening, obtain photometric metallicity estimates, and, for the first time, present a detailed abundance analysis of 10 potential cluster stars (nine clump stars and one Cepheid). Using the radial position from the cluster center and multiple color indices, we have isolated a sample of unevolved, probable single-star members of Tombaugh 1. From 51 stars, the cluster reddening is found to be -.008, where the errors refer to the internal standard errors of the mean. The weighted photometric metallicity from m 1 and hk is [Fe/H]=−0.10±0.02, while a match to the Victoria-Regina Strömgren isochrones leads to an age of 0.95±0.10 Gyr and an apparent modulus of -m M ( )=13.10±0.10. Radial velocities identify six giants as probable cluster members, and the elemental abundances of Fe, Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Y, Ba, Ce, and Nd have been derived for both the cluster and the field stars. Tombaugh 1 appears to be a typical inner thin disk, intermediate-age open cluster of slightly subsolar metallicity, located just beyond the solar circle, with solar elemental abundance ratios except for the heavy s-process elements, which are a factor of two above solar. Its metallicity is consistent with a steep metallicity gradient in the galactocentric region between 9.5 and 12 kpc. Our study also shows that Cepheid XZ CMa is not a member of Tombaugh 1 and reveals that this Cepheid presents signs of barium enrichment, making it a probable binary star.

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Memorial for Louis H. Fuchs (1915–1991)

Cited by 71 publications

References 10 publications

Absolute dimensions of solar-type eclipsing binaries.

Absolute dimensions of solar-type eclipsing binaries.

Differential asteroseismic study of seismic twins observed by CoRoT

PROPERTIES OF THE OPEN CLUSTER TOMBAUGH 1 FROM HIGH-RESOLUTION SPECTROSCOPY AND uvbyCaHβ PHOTOMETRY*

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