Short-term spectroscopic variability of Plaskett’s star

Palate, Matthieu; Rauw, Grégor

doi:10.1051/0004-6361/201423608

Cited by 12 publications

(11 citation statements)

References 22 publications

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“…Furthermore, the bulge shape is not smooth, but consists of smaller-scale structures. These can be most easily visualized in the plot shown below the map, which shows the radius at the equator plotted as a phase-dependent variation in the line-profiles is expected due to gravity darkening effects, see Zuiderwijk et al 1977;and Palate & Rauw, 2011. Fig. 3.…”

Section: The "Standard" Casementioning

confidence: 99%

Tidal effects on the radial velocity curve of HD 77581 (Vela X-1)

Koenigsberger¹,

Moreno²,

Harrington³

2012

A&A

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Context. The mass of the neutron star in Vela X-1 has been found to be larger than the canonical 1.5 M . This result relies on the assumption that the amplitude of the optical component's measured radial velocity curve is not seriously affected by the interactions in the system. Aims. Our aim is to explore the effect on the radial velocity curve caused by surface motions excited by tidal interactions. Methods. We use a calculation from first principles that involves solving the equations of motion of a Lagrangian grid of surface elements. The velocities on the visible surface of the star are projected along the line-of-sight to the observer to obtain the Doppler shifts which are applied to the local line-profiles, which are then combined to obtain the absorption-line profile in the observer's reference frame. The centroid of the line-profiles for different orbital phases is then measured and a simulated RV curve constructed. Models are run for the "standard" (v sin i = 116 km s −1 ) and "slow" (56 km s −1 ) supergiant rotation velocities. Results. The surface velocity field is complex and includes fast, small-spatial scale structures. It leads to strong variability in the photospheric line profiles which, in turn, causes significant deviations from a Keplerian RV curve. The peak-to-peak amplitudes of model RV curves are in all cases larger than the amplitude of the orbital motion. Keplerian fits to RV curves obtained with the "standard" rotation velocity imply m ns ≥ 1.7 M . However, a similar analysis of the "slow" rotational velocity models allows for m ns ∼ 1.5 M . Thus, the stellar rotation plays an important role in determining the characteristics of the perturbed RV curve. Conclusions. Given the observational uncertainty in GP Vel's projected rotation velocity and the strong perturbations seen in the published and the model RV curves, we are unable to rule out a small (∼1.5 M ) mass for the neutron star companion.

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Section: The "Standard" Casementioning

confidence: 99%

Tidal effects on the radial velocity curve of HD 77581 (Vela X-1)

Koenigsberger¹,

Moreno²,

Harrington³

2012

A&A

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“…This spacing suggests that there are tidal interactions associated with these signals. This is not unprecented as the work of Palate & Rauw (2014), Koenigsberger et al (2006) and Palate et al (2013) also show some evidence of effects caused by tidal forces in massive binaries. This variability, though, is unlikely to arise from tidally excited oscillations, which occur at integer harmonics of the orbital frequency (Fuller et al 2012, Burkart et al 2012, Welsh et al 2011, in contrast to the oscillations we observe.…”

Section: Photometric Time-series Analysismentioning

confidence: 97%

A COORDINATED X-RAY AND OPTICAL CAMPAIGN OF THE NEAREST MASSIVE ECLIPSING BINARY,δORIONIS Aa. III. ANALYSIS OF OPTICAL PHOTOMETRIC (MOST) AND SPECTROSCOPIC (GROUND-BASED) VARIATIONS

Pablo

Richardson

Moffat

et al. 2015

ApJ

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We report on both high-precision photometry from the Microvariability and Oscillations of Stars (MOST) space telescope and ground-based spectroscopy of the triple system δ Ori A, consisting of a binary O9.5II+early-B (Aa1 and Aa2) with P = 5.7 days, and a more distant tertiary (O9 IV P 400 > years). This data was collected in concert with X-ray spectroscopy from the Chandra X-ray Observatory. Thanks to continuous coverage for three weeks, the MOST light curve reveals clear eclipses between Aa1 and Aa2 for the first time in non-phased data. From the spectroscopy, we have a well-constrained radial velocity (RV) curve of Aa1. While we are unable to recover RV variations of the secondary star, we are able to constrain several fundamental parameters of this system and determine an approximate mass of the primary using apsidal motion. We also detected second order modulations at 1 12 separate frequencies with spacings indicative of tidally influenced oscillations. These spacings have never been seen in a massive binary, making this system one of only a handful of such binaries that show evidence for tidally induced pulsations.

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“…This has a direct effect on evolution of these stars and its X‐ray luminosity. Currently, all known strongly magnetic O stars are slow rotators, with the exception of Plaskett's star, where interactions within the binary are speculated to play an additional role in spinup of the primary (Grunhut et al ; Palate & Rauw ).…”

Section: Mhd Simulationsmentioning

confidence: 99%

Magnetic fields in massive stars and magnetically confined winds

ud‐Doula

2017

Astron Nachr

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Massive stars (at least 8 times as massive as the Sun) possess strong stellar winds driven by radiation. With the advent of collaborations like MiMeS or BOB, an increasing number of these massive stars have been confirmed to have global magnetic fields. Such magnetic fields can have significant influence on the dynamics of these stellar winds, which are strongly ionized. Such interaction of the wind and magnetic field can generate copious amount of X‐rays, can spin the star down, and can also help form large‐scale disk‐like structures. In this paper, we discuss the nature of such radiatively driven winds and how they interact with magnetic fields, often leading to confined winds.

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Short-term spectroscopic variability of Plaskett’s star

Cited by 12 publications

References 22 publications

Tidal effects on the radial velocity curve of HD 77581 (Vela X-1)

Tidal effects on the radial velocity curve of HD 77581 (Vela X-1)

A COORDINATED X-RAY AND OPTICAL CAMPAIGN OF THE NEAREST MASSIVE ECLIPSING BINARY,δORIONIS Aa. III. ANALYSIS OF OPTICAL PHOTOMETRIC (MOST) AND SPECTROSCOPIC (GROUND-BASED) VARIATIONS

Magnetic fields in massive stars and magnetically confined winds

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