Observational signatures of past mass-exchange episodes in massive binaries: The case of HD 149 404

Raucq, Françoise; Rauw, Grégor; Gosset, Éric; Nazé, Yaël; Mahy, L.; Hervé, Anthony; Martins, F.

doi:10.1051/0004-6361/201527543

Cited by 26 publications

(48 citation statements)

References 54 publications

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“…We adopted a volume filling factor at terminal velocity of 0.1 and a clumping velocity factor of 100 km s −1 ; for the clumping formalism implemented in CMFGEN, see e.g. Raucq et al (2016). The following elements are included in the calculations of our models: H, He, C, N, O, Ne, Mg, Al, Si, P, S, Ca, Fe, and Ni.…”

Section: Methods For the Hotter Starsmentioning

confidence: 99%

“…Typical errors on T eff and log g were assumed to be 1500 K and 0.15 dex, respectively, as generally adopted in CMFGEN analyses in the literature (Martins et al 2015b;Raucq et al 2016). These values are higher than those considered for DE-TAIL/SURFACE since stronger winds have an impact on the resultant spectrum, making the analysis more challenging.…”

Section: Hotter Starsmentioning

confidence: 99%

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Chemical abundances of fast-rotating massive stars

Cazorla

Morel

Nazé

et al. 2017

A&A

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Aims. Recent observations have challenged our understanding of rotational mixing in massive stars by revealing a population of fastrotating objects with apparently normal surface nitrogen abundances. However, several questions have arisen because of a number of issues, which have rendered a reinvestigation necessary; these issues include the presence of numerous upper limits for the nitrogen abundance, unknown multiplicity status, and a mix of stars with different physical properties, such as their mass and evolutionary state, which are known to control the amount of rotational mixing. Methods. We have carefully selected a large sample of bright, fast-rotating early-type stars of our Galaxy (40 objects with spectral types between B0.5 and O4). Their high-quality, high-resolution optical spectra were then analysed with the stellar atmosphere modelling codes DETAIL/SURFACE or CMFGEN, depending on the temperature of the target. Several internal and external checks were performed to validate our methods; notably, we compared our results with literature data for some well-known objects, studied the effect of gravity darkening, or confronted the results provided by the two codes for stars amenable to both analyses. Furthermore, we studied the radial velocities of the stars to assess their binarity.Results. This first part of our study presents our methods and provides the derived stellar parameters, He, CNO abundances, and the multiplicity status of every star of the sample. It is the first time that He and CNO abundances of such a large number of Galactic massive fast rotators are determined in a homogeneous way.

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Section: Methods For the Hotter Starsmentioning

confidence: 99%

Section: Hotter Starsmentioning

confidence: 99%

Chemical abundances of fast-rotating massive stars

Cazorla

Morel

Nazé

et al. 2017

A&A

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“…A recent, more detailed study further reveals an asynchronous rotation of the two stars, a significant nitrogen overabundance of the secondary star, and peculiar positions of the stars in the HR diagram (Raucq et al 2016). All of these properties clearly disagree with expectations of single star evolutionary models, yielding further support to the past mass-exchange scenario (Raucq et al 2016). …”

Section: The Samplementioning

confidence: 95%

How unique is Plaskett’s star? A search for organized magnetic fields in short period, interacting or post-interaction massive binary systems

Nazé

Neiner

Grunhut

et al. 2017

Mon. Not. R. Astron. Soc.

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Amongst O-type stars with detected magnetic fields, the fast rotator in the close binary called Plaskett's star shows a variety of unusual properties. Since strong binary interactions are believed to have occurred in this system, one may wonder about their potential role in generating magnetic fields. Stokes V spectra collected with the low-resolution FORS2 and high-resolution ESPaDOnS and Narval spectropolarimeters were therefore used to search for magnetic fields in 15 interacting or post-interaction massive binaries. No magnetic field was detected in any of them, with 0 G always being within 2σ of the derived values. For 17 out of 25 stars in the systems observed at high-resolution, the 90% upper limit on the individual dipolar fields is below the dipolar field strength of Plaskett's secondary; a similar result is found for five out of six systems observed at low resolution. If our sample is considered to form a group of stars sharing similar magnetic properties, a global statistical analysis results in a stringent upper limit of ∼ 200 G on the dipolar field strength. Moreover, the magnetic incidence rate in the full sample of interacting or post-interaction systems (our targets + Plaskett's star) is compatible with that measured from large surveys, showing that they are not significantly different from the general O-star population. These results suggest that binary interactions play no systematic role in the magnetism of such massive systems.

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“…Spectral disentangling can only reconstruct features that are well sampled by the Doppler excursions during the orbital cycle. In practice, this often leads to artifacts in the wings of broad lines, such as the H i Balmer lines, if these lines only partially deblend over the orbital cycle (e.g., Raucq et al 2016). However, in the case of HD 152 248, the RV amplitudes are sufficient to ensure a reliable reconstruction of the wings of the Balmer absorption lines.…”

Section: Limitations Of the Methodsmentioning

confidence: 99%

Apsidal motion in the massive binary HD 152248

Rosu¹,

Rauw²,

Gosset³

et al. 2020

caosp

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Context. The eccentric massive binary HD 152 248 (also known as V1007 Sco), which hosts two O7.5 III-II(f) stars, is the most emblematic eclipsing O-star binary in the very young and rich open cluster NGC 6231. Its properties render the system an interesting target for studying tidally induced apsidal motion. Aims. Measuring the rate of apsidal motion in such a binary system gives insight into the internal structure and evolutionary state of the stars composing it. Methods. A large set of optical spectra was used to reconstruct the spectra of the individual binary components and establish their radial velocities using a disentangling code. Radial velocities measured over seven decades were used to establish the rate of apsidal motion. We furthermore analysed the reconstructed spectra with the CMFGEN model atmosphere code to determine stellar and wind properties of the system. Optical photometry was analysed with the Nightfall binary star code. A complete photometric and radial velocity model was constructed in PHOEBE 2 to determine robust uncertainties. Results. We find a rate of apsidal motion of (1.843 +0.064 −0.083 ) • yr −1 . The photometric data indicate an orbital inclination of (67.6 +0.2 −0.1 ) • and Roche-lobe filling factors of both stars of about 0.86. Absolute masses of 29.5 +0.5 −0.4 M and mean stellar radii of 15.07 +0.08 −0.12 R are derived for both stars. We infer an observational value for the internal structure constant of both stars of 0.0010 ± 0.0001. Conclusions. Our in-depth analysis of the massive binary HD 152 248 and the redetermination of its fundamental parameters can serve as a basis for the construction of stellar evolution models to determine theoretical rates of apsidal motion to be compared with the observational one. In addition, the system hosts two twin stars, which offers a unique opportunity to obtain direct insight into the internal structure of the stars.A&A proofs: manuscript no. 37285corr the spectral disentangling are combined with data from the literature in Sect. 4 to establish a preliminary value for the observational rate of apsidal motion. The possibility of a triple system is discussed in Appendix D. Photometric data of HD 152 248 are analysed in Sect. 5 by means of the Nightfall binary star code. In Sect. 6 we construct a complete model in PHOEBE 2 that takes photometric and radial velocity (RV) measurements into account. We determine robust uncertainties on the parameters based on this model. The observational internal structure constant k 2 of the stars is determined in Sect. 7. Finally, we discuss the implications of our study and give our conclusions in Sect. 8. Observational data SpectroscopyTo investigate the optical spectrum of HD 152 248, we extracted 48 high-resolution échelle spectra. Of these, 27 were obtained with the Fiber-fed Extended Range Optical Spectrograph (FEROS) mounted on the European Southern Observatory (ESO) 1.5 m or 2.2 m telescopes in La Silla, Chile (Kaufer et al. 1999). The remaining 21 spectra were obtained with the ES-PaDOns spectrogr...

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Observational signatures of past mass-exchange episodes in massive binaries: The case of HD 149 404

Cited by 26 publications

References 54 publications

Chemical abundances of fast-rotating massive stars

Chemical abundances of fast-rotating massive stars

How unique is Plaskett’s star? A search for organized magnetic fields in short period, interacting or post-interaction massive binary systems

Apsidal motion in the massive binary HD 152248

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