The Observatory Magazine: Linking Three Centuries

Stickland, D. J.

doi:10.1007/978-94-010-0049-9_14

Cited by 26 publications

(50 citation statements)

References 1 publication

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“…Though the equivalent widths of the absorption lines of the close binary display some variations, we could not find any significant phase‐locked variations that might be related to the so‐called ‘Struve–Sahade’ effect (e.g. Stickland 1997). The only possible exception is the He i λ 4471 line that appears stronger in the primary spectrum around orbital phases when the star is approaching, while the EW of the secondary's line does not vary.…”

Section: The Spectrum Of Tr 16‐104contrasting

confidence: 65%

Optical spectroscopy of XMEGA targets in the Carina Nebula - III. The multiple system Tr 16-104 ( CPD -59 2603)

Rauw¹,

Sana²,

Antokhin³

et al. 2001

Monthly Notices of the Royal Astronomical Society

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We discuss the orbital elements of the multiple system Tr 16‐104 which is usually believed to be a member of the open cluster Trumpler 16 in the Carina complex. We show that Tr 16‐104 could be a hierarchical triple system consisting of a short‐period (2.15 d) eclipsing O7 V+O9.5 V binary bound to a B0.2 IV star. Our preliminary orbital solution of the third body indicates that the B star most probably describes an eccentric orbit with a period of ∼285 or ∼1341 d around the close binary. Folding photometric data from the literature with our new ephemerides, we find that the light curve of the close binary exhibits rather narrow eclipses indicating that the two O stars must be well inside their Roche lobes. Our analysis of the photometric data yields a lower limit on the inclination of the orbit of the close binary of i≥77°. The stellar radii and luminosities of the O7 V and O9.5 V stars are significantly smaller than expected for stars of this spectral type. Our results suggest that Tr 16‐104 lies at a distance of the order of 2.5 kpc and support a fainter absolute magnitude for zero‐age main‐sequence O stars than usually adopted. We find that the dynamical configuration of Tr 16‐104 corresponds to a hierarchical system that should remain stable provided that it suffers no strong perturbation. Finally, we also report long‐term temporal variations of high‐velocity interstellar Ca ii absorptions in the line of sight towards Tr 16‐104.

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Section: The Spectrum Of Tr 16‐104contrasting

confidence: 65%

Optical spectroscopy of XMEGA targets in the Carina Nebula - III. The multiple system Tr 16-104 ( CPD -59 2603)

Rauw¹,

Sana²,

Antokhin³

et al. 2001

Monthly Notices of the Royal Astronomical Society

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“…Gies et al (1997) suggested instead that the phenomenon might be due to heating by the back-scattering of photons by the stellar-wind interaction zone. Stickland (1997) proposed that the Struve-Sahade effect could be linked to a combination of several mechanisms. Gayley (2002) and Gayley et al (2007) argued that this effect could be linked to flows at the surface of the stars.…”

Section: Struve-sahade Effectmentioning

confidence: 99%

Spectral modelling of circular massive binary systems

Palate

Rauw

2012

A&A

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Context. Some secondary effects are known to introduce variations in spectra of massive binaries. These phenomena, such as the Struve-Sahade effect and the difficulties in determining properly the spectral type have been reported and documented in the literature. Aims. We simulate the spectra of circular massive binaries at different phases of the orbital cycle and account for the gravitational influence of the companion star on the shape and physical properties of the stellar surface. Methods. We use the Roche potential to compute the stellar surface, von Zeipel theorem, and reflection effects to compute the surface temperature. We then interpolate in a grid of non-local thermodynamic equilibrium (NLTE) plan-parallel atmosphere model spectra to obtain the local spectrum at each surface point. We finally sum all the contributions, accounting for the reflection, Doppler shift, and limb-darkening to obtain the total spectrum. The computation is done for different orbital phases and for different sets of physical and orbital parameters. Results. Our models reproduce the Struve-Sahade effect for several lines. Another effect on the surface temperature distribution is visible but the distribution predicted by our current model is not yet consistent with observations. Conclusions. In some cases, the Struve-Sahade effect as well as more complex line intensity variations could be linked to blends of intrinsically asymmetric line profiles that are not appropriately treated by the deblending routine. Systematic variations in the lines of (nearly) contact systems are also predicted by the model.

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“…The rms noise expected from the ATCA, 0.050 mJy, is 8σ lower than the reported VLA flux limit of 0.4 mJy. The masses of both the primary and secondary stars are in the range 20-30 M , the primary being the more evolved star (Hutchings 1977;Stickland 1989). Wiggs & Gies (1993) interpreted the Hα P Cygni profile by means of a model where emission comes from inside the wind of the primary and from a plane midway between the stars where the winds collide.…”

Section: The Target Starsmentioning

confidence: 99%

Mass loss rate determination of southern OB stars

Benaglia

Cappa

Koribalski

2001

A&A

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Abstract.A sample of OB stars (eleven Of, one O and one B supergiant) has been surveyed with the Australia Telescope Compact Array at 4.8 and 8.64 GHz with a resolution of ∼2 -4 . Five stars were detected; three of them have negative spectral indices, consistent with non-thermal emission, and two have positive indices. The thermal radiation from HD 150135 and HD 163181 can be explained as coming from an optically thick ionized stellar wind. The non-thermal radiation from CD-47• 4551, HD 124314 and HD 150136 possibly comes from strong shocks in the wind itself and/or in the wind colliding region if the stars have a massive early-type companion. The percentage of non-thermal emitters among detected O stars has increased up to ∼50%. The Of star HD 124314 clearly shows flux density variations. Mass loss rates (or upper limits) were derived for all the observed stars and the results compared with non-radio measurements and theoretical predictions.

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The Observatory Magazine: Linking Three Centuries

Cited by 26 publications

References 1 publication

Optical spectroscopy of XMEGA targets in the Carina Nebula - III. The multiple system Tr 16-104 ( CPD -59 2603)

Optical spectroscopy of XMEGA targets in the Carina Nebula - III. The multiple system Tr 16-104 ( CPD -59 2603)

Spectral modelling of circular massive binary systems

Mass loss rate determination of southern OB stars

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