Erratum: “A Grid of Non‐LTE Line‐blanketed Model Atmospheres of O‐Type Stars” (ApJS, 146, 417 [2003]):

Lanz, T.; Hubený, I.

doi:10.1086/377130

Cited by 404 publications

(626 citation statements)

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“…The corresponding FWHMs are 3.1 and 3.3Å, and the EWs 0.47 and 0.95Å, respectively. Such values agree with spectral type O8 I (according to OSTAR synthetic spectra by Lanz & Hubeny 2003 and O-star parameters by Martins et al 2005). Leitherer et al (1987) To show the eclipsing component line profiles, lines of the third star were subtracted.…”

supporting

confidence: 70%

Peculiarities in the Spectrum of the Early-type System MY Ser

2011

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Abstract. MY Ser is an eclipsing early-type contact system. Both components are of spectral type O6 III. Using ESO archive spectra, we show that the radial velocity of the third body, which contributes about half of the total luminosity, changed from 2006 to 2009. The line profiles of the eclipsing system have peculiar shapes and strengths; namely around conjunctions, they are affected by circumbinary matter. The eclipsing binary MY Ser (HD 167791) belongs to the rare class of early-type contact systems. It has a period of 3.32 days, its magnitude in maximum is V = 7.3, and both minima have depths of 0.3 mag. The integral spectrum was classified as O8 Ib(f)p by Walborn (1972). Leitherer et al. (1987) found that the spectrum is dominated by lines of a third component, probably of spectral type O8 Ib, and that the lines of the eclipsing components belong to stars of earlier type. Mayer et al. (2010) solved the UBV light curves and derived an overcontact solution with a large filling factor.The ESO archive contains 150 FEROS spectra of MY Ser, taken in the years 2008 and 2009 (plus one spectrum from 2006). These spectra are available in a pipeline processed form. We chose He I 5876 and He II 5411Å lines for this study, selected about half of the available spectra and averaged groups of them to represent 22 different phase points. We fitted Gaussian profiles to obtain the positions, widths, and depths of all line components.

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supporting

confidence: 70%

Peculiarities in the Spectrum of the Early-type System MY Ser

2011

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“…To start our analysis, we used a new grid of TLUSTY model atmospheres based on the OSTAR2002 grid (Lanz & Hubeny 2003 were also checked for consistency. Typical errors for T eff range from 1 to 2 kK.…”

Section: Methodsmentioning

confidence: 99%

Analysis of Galactic late-type O dwarfs: more constraints on the weak wind problem

Marcolino

Bouret

Martins

et al. 2009

A&A

117

169

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Aims. We investigate the stellar and wind properties of a sample of late-type O dwarfs. Previous analyses of such stars have found very low mass-loss rates; rates much lower than predicted by theory (the weak wind problem). Methods. Far-UV to optical spectra of five Galactic O stars were analyzed: HD 216898 (O9IV/O8.5V), HD 326329 (O9V), HD 66788 (O8V/O9V), ζ Oph (O9.5Vnn), and HD 216532 (O8.5V((n))). We used a grid of TLUSTY models to obtain effective temperatures, gravities, rotational velocities, and to identify wind lines. Wind parameters for each object were obtained using expanding atmosphere models calculated with the CMFGEN code.Results. The spectra of our sample have primarily a photospheric origin. A weak wind signature is seen in C iv λλ1548, 1551, from which mass-loss rates consistent with previous CMFGEN results for O8-O9V stars were derived (∼10 −10 −10 −9 M yr −1 ). A discrepancy of roughly two orders of magnitude is found between these mass-loss rates and the values predicted by theory (Ṁ Vink ), confirming a breakdown or a steepening of the modified wind momentum-luminosity relation at log L /L < ∼ 5.2. We have estimated the carbon abundance for the stars of our sample and concluded that its value cannot be reduced to sufficiently small values to solve the weak wind problem. Upper limits onṀ were established for all objects using lines of different ions: P v λλ1118, 1128, C iii λ1176, N v λλ1239, 1243, Si iv λλ1394, 1403, and N iv λ1718. All the values obtained are in disagreement with theoretical predictions, bringing support to the reality of weak winds. Together with C iv λλ1548, 1551, the use of N v λλ1239, 1243 results in the lowest mass-loss rates: the upper limits indicate thatṀ must be less than about −1.0 dexṀ Vink . Upper mass-loss rate limits obtained for other transitions are also low: they indicate thatṀ must be less than about (−0.5 ± 0.2) dexṀ Vink . We studied the behavior of the Hα line with different mass-loss rates. For two stars, only models with very lowṀ's provide the best fit to the UV and optical spectra. We also explored ways to fit the observed spectra with the theoretical mass-loss rates. By using large amounts of X-rays, we could reduce the predicted wind emission to the observed levels. However, unrealistic X-ray luminosities had to be used (log L X /L Bol > ∼ −3.5). The validity of the models used in our analyses is discussed.

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“…A significant part of the ionic models was taken from the TLUSTY code (Lanz & Hubeny 2003. For phosphorus we employed data described by Pauldrach et al (2001).…”

Section: Model Assumptionsmentioning

confidence: 99%

X-ray emission from hydrodynamical simulations in non-LTE wind models

Krtička

Feldmeier

Oskinova

et al. 2009

A&A

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Hot stars are sources of X-ray emission originating in their winds. Although hydrodynamical simulations that are able to predict this X-ray emission are available, the inclusion of X-rays in stationary wind models is usually based on simplifying approximations. To improve this, we use results from time-dependent hydrodynamical simulations of the line-driven wind instability (seeded by the base perturbation) to derive the analytical approximation of X-ray emission in the stellar wind. We use this approximation in our non-LTE wind models and find that an improved inclusion of X-rays leads to a better agreement between model ionization fractions and those derived from observations. Furthermore, the slope of the L X − L relation is in better agreement with observations, however the X-ray luminosity is underestimated by a factor of three. We propose a possible solution for this discrepancy.

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Erratum: “A Grid of Non‐LTE Line‐blanketed Model Atmospheres of O‐Type Stars” (ApJS, 146, 417 [2003]):

Cited by 404 publications

References 0 publications

Peculiarities in the Spectrum of the Early-type System MY Ser

Peculiarities in the Spectrum of the Early-type System MY Ser

Analysis of Galactic late-type O dwarfs: more constraints on the weak wind problem

X-ray emission from hydrodynamical simulations in non-LTE wind models

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