Nonlinear Limb Darkening for Early-Type Stars

Klinglesmith, Daniel A.; Sobieski, Stanley

doi:10.1086/110960

Cited by 121 publications

(96 citation statements)

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“…These results were used to estimate the limb darkening (LD) coefficients, that were held fixed during the major fit, but perturbed during the RS stage. We used the logarithmic limb darkening law (Klinglesmith & Sobieski 1970), with the coefficients interpolated from the tables published on the PHOEBE website 9 . We found that results do not change significantly if we put LD coefficients predicted for temperatures and gravities different by 150 K and 0.5 dex.…”

Section: Light Curve Solutions and Absolute Parametersmentioning

confidence: 99%

HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field – II. Double- and triple-lined objects

Hełminiak

Ukita

Kambe

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present the results of our spectroscopic observations of eight detached eclipsing binaries (DEBs), selected from the Kepler Eclipsing Binary Catalog. Radial velocities (RVs) were calculated from high resolution spectra obtained with the HIDES spectrograph, attached to the 1.88-m telescope of the Okayama Astrophysical Observatory, and were used to characterize the targets in combination with the Kepler light curves. For each binary we obtained a full set of orbital and physical parameters, reaching precision below 3% in masses and radii for 5 pairs. By comparing our results with theoretical models, we assess the distance, age and evolutionary status of the researched objects. We also study eclipse timing variations of selected objects, and identify a new system with a γDor pulsator. Two systems are triples, and show lines coming from three components. In one case the motion of the outer star and the perturbation in the RVs of the inner binary are clearly visible and periodical, which allows us to directly calculate the mass of the third star, and inclination of the outer orbit. In the second case we only see a clear motion of the tertiary, and investigate two scenarios: that it is a linear trend coming from the orbital motion around the inner binary, and that it is caused by a planetary mass companion. When possible, we also compare our results with the literature, and conclude that only by combining photometry with RVs it is possible to obtain correct physical parameters of both components of a DEB.

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Section: Light Curve Solutions and Absolute Parametersmentioning

confidence: 99%

HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field – II. Double- and triple-lined objects

Hełminiak

Ukita

Kambe

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…If adjusted, the coefficients for the components of VZ Hya and WZ Oph turn out closest to the values by van Hamme; for AD Boo the coefficients either become unrealistic or convergence is not achieved at all. In addition, a few WD analyses with the non-linear law by Klinglesmith & Sobieski (1970) and coefficients by van Hamme (1993) were included. No improvements in the light curve fits were seen.…”

Section: Photometric Analysesmentioning

confidence: 99%

Absolute dimensions of eclipsing binaries. XXVI.

Clausen¹,

Torres

Bruntt

et al. 2008

A&A

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Context. Accurate mass, radius, and abundance determinations from binaries provide important information on stellar evolution, fundamental to central fields in modern astrophysics and cosmology. Aims. We aim to determine absolute dimensions and abundances for the three F-type main-sequence detached eclipsing binaries AD Boo, VZ Hya, and WZ Oph and to perform a detailed comparison with results from recent stellar evolutionary models. Methods. uvby light curves and uvbyβ standard photometry were obtained with the Strömgren Automatic Telescope at ESO, La Silla, radial velocity observations at CfA facilities, and supplementary high-resolution spectra with ESO's FEROS spectrograph. State-ofthe-art methods were applied for the analyses: the EBOP and Wilson-Devinney binary models, two-dimensional cross-correlation and disentangling, and the VWA abundance analysis tool. Results. Masses and radii that are precise to 0.5-0.7% and 0.4-0.9%, respectively, have been established for the components, which span the ranges of 1.1 to 1.4 M and 1.1 to 1.6 R . The [Fe/H] abundances are from -0.27 to +0.10, with uncertainties between 0.07 and 0.15 dex. We find indications of a slight α-element overabundance of [α/Fe] ∼ +0.1 for WZ Oph. The secondary component of AD Boo and both components of WZ Oph appear to be slightly active. Yale-Yonsai and Victoria-Regina evolutionary models fit the components of AD Boo and VZ Hya almost equally well, assuming coeval formation, at ages of about 1.75/1.50 Gyr (AD Boo) and 1.25/1.00 Gyr (VZ Hya). BaSTI models, however, predict somewhat different ages for the primary and secondary components. For WZ Oph, the models from all three grids are significantly hotter than observed. A low He content, decreased envelope convection coupled with surface activity, and/or higher interstellar absorption would remove the discrepancy, but its cause has not been definitively identified. Conclusions. We have demonstrated the power of testing and comparing recent stellar evolutionary models using eclipsing binaries, provided their abundances are known. The strongest limitations and challenges are set by T eff and interstellar absorption determinations, and by their effects on and correlation with abundance results.

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“…The bolometric albedo and the gravity-brightening coefficients were both set at the canonical value of 1.0 for stars with radiative envelopes. For the limb darkening we used a logarithmic law as defined in Klinglesmith & Sobieski (1970), with first-and second-order coefficients interpolated at each iteration for the exact T eff and log g of each component from a set of tables computed in advance using a grid of ATLAS9 model atmospheres. A mass ratio of q ¼ M S =M P ¼ 0:407 was adopted from the spectroscopic solution (x 3.2), and the temperature of the primary component was set to T P eff ¼ 26; 450 K, as discussed in x 3.3.…”

Section: The Light Curvementioning

confidence: 99%

Fundamental Properties and Distances of Large Magellanic Cloud Eclipsing Binaries. IV. HV 5936

Fitzpatrick

Ribas

Guinan

et al. 2003

ApJ

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We have determined the fundamental properties and distance of a fourth eclipsing binary (EB) system in the Large Magellanic Cloud, HV 5936 ($B0.5 V + $B2 III). As in our previous studies, we combine '' classical '' EB light-curve and radial velocity curve analyses with modeling of the UV/optical spectral energy distribution of HV 5936 to produce a detailed characterization of the system. In this paper, we also include an analysis of the high-resolution optical absorption line spectra of the binary components. We find HV 5936 to be an Algol-class system, in which the masses of the primary and secondary stars have evolved via mass transfer to their current values of 11.6 and 4.7 M , respectively. The properties of the primary star are indistinguishable from those of a '' normal '' star of the same current mass. The secondary is found to be overluminous for its current mass and exhibits a factor of 2 enhancement in its surface He abundance. These results are compatible with case A mass exchange occurring during the core hydrogen-burning phase of the current secondary. The distance derived to the system, 43:2 AE 1:8 kpc, implies a distance of $44.3 kpc to the optical center of the LMC. This is several kiloparsecs closer than found in our analyses of other systems, and we suggest that HV 5936 lies '' above '' the LMC disk. This is supported by the very low interstellar H i column density and low E(BÀV ) found for the system-both of which are consistent with expected Milky Way foreground material-and may be associated with HV 5936's location near the LMC supergiant shell LMC 4.

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Nonlinear Limb Darkening for Early-Type Stars

Cited by 121 publications

References 1 publication

HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field – II. Double- and triple-lined objects

HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field – II. Double- and triple-lined objects

Absolute dimensions of eclipsing binaries. XXVI.

Fundamental Properties and Distances of Large Magellanic Cloud Eclipsing Binaries. IV. HV 5936

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