Wind Variability of B Supergiants. I. The Rapid Rotator HD 64760 (B0.5 Ib)

Massa, Derck; Prinja, R. K.; Fullerton, A. W.

doi:10.1086/176353

Cited by 88 publications

(104 citation statements)

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“…When velocity shifts are detected (e.g., broad ripples traveling bluewards, as in NGC 6826), typical accelerations are in the range 0.01-0.05 km s −2 , with features traveling a few tenths of the corresponding terminal velocities in time intervals of a few hours. The time scales of the variable features of CSPNe to travel along the troughs of the P Cygni profiles seem shorter than those of OB stars, which are typically in the range of a few days (e.g., Howarth et al 1995;Massa et al 1995;Fullerton et al 1997). If we assume these velocity shifts are associated to the stellar rotation, as is the case for OB stars, and consequently we conclude that the rotation periods of CSPNe are of the order or greater than a few hours, then for typical radii (0.2-0.5 R ) and an assumed solid body rotation, the rotational velocities of our sample would be in the range 50-150 km s −1 .…”

Section: Characteristics Of Time-variable Featuresmentioning

confidence: 99%

Analysis of far-UV data of central stars of planetary nebulae: Occurrence and variability of stellar winds

Guerrero

Marco

2013

A&A

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The occurrence of stellar wind in the central star of a planetary nebula (CSPN) can be revealed by the presence of P Cygni profiles of high-excitation lines overimposed on its stellar continuum. We examined the entire Far-Ultraviolet Spectroscopic Explorer (FUSE) archive and merged all useful spectroscopic observations of CSPNe to produce the highest quality spectra that can be used to assess the frequency of stellar winds. Furthermore, the individual spectra of each CSPN were compared to search for variability in the P Cygni profile. P Cygni profiles of high-excitation lines have been found in 44 CSPNe, with a clear correlation between the ionization potential of the lines and the effective temperature of the star. We introduce a prescription to derive the terminal wind velocity (v ∞ ) from saturated and unsaturated P Cygni profiles and provide new values of v ∞ for these stars. Another 23 CSPNe do not show P Cygni profiles, or else their data in the FUSE archive are not conclusive enough to determine the occurrence of P Cygni profiles. Variability in the P Cygni profile of high-excitation, far-UV lines is found for the first time in six CSPNe, namely Hen 2-131, NGC 40, NGC 1535, NGC 2392, Sp 3, and SwSt 1. This increases up to 13 the number of CSPNe with variable P Cygni profiles in the UV, including those previously reported using IUE or FUSE observations. Variability is seen primarily in the unsaturated P v and Si iv lines, but also in saturated C iii and O vi lines. The CSPNe with variable P Cygni profiles have similar stellar properties (relatively low log (g) and T eff ) that suggest they are less evolved CSPNe. Some of the CSPNe with variable P Cygni profiles show O vi lines, while their effective temperature is insufficient to produce this ion. We suggest that this ion is produced by Auger ionization from X-rays associated to shocks in their stellar winds, as is the case in massive OB stars of high ionization potential ions that cannot be abundantly produced by photoionizations.

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Section: Characteristics Of Time-variable Featuresmentioning

confidence: 99%

Analysis of far-UV data of central stars of planetary nebulae: Occurrence and variability of stellar winds

Guerrero

Marco

2013

A&A

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“…Numerous time resolved observations of O stars like the FEROS campaigns on HD 152408 (O8 If) (Prinja et al 2001) and particularly the IUE MEGA campaign on HD 64760 (B0.5 Ib) Massa et al 1995) and on ζ Puppis (O4 I(n)f) (Howarth et al 1995) as well as the extended optical HEROS campaigns over typically 100 consecutive nights on late B-and A&A 566, A125 (2014) change the lower boundary condition of the stellar wind, which in turn can cause localised structural changes in the wind. These structural changes modulate the observed stellar wind profiles as they are dragged through the line of sight to a distant observer by underlying rotation of the star.…”

Section: Introductionmentioning

confidence: 99%

The variable stellar wind of Rigel probed at high spatial and spectral resolution

Chesneau¹,

Kaufer²,

Stahl³

et al. 2014

A&A

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Context. Luminous BA-type supergiants are the brightest stars in the visible that can be observed in distant galaxies and are potentially accurate distance indicators. The impact of the variability of the stellar winds on the distance determination remains poorly understood. Aims. Our aim is to probe the inhomogeneous structures in the stellar wind using spectro-interferometric monitoring.Methods. We present a spatially resolved, high-spectral resolution (R = 12 000) K-band temporal monitoring of the bright supergiant β Orionis (Rigel, B8 Iab) using AMBER at the Very Large Telescope Interferometer (VLTI). period is much quieter with virtually no detectable variations in the dispersed visibilities but a strong S-shaped signal is observed in differential phase coinciding with a strong ejection event discernible in the optical spectra. The differential phase signal that is sometimes detected is reminiscent of the signal computed from hydrodynamical models of corotating interaction regions. For some epochs the temporal evolution of the signal suggests the rotation of the circumstellar structures.

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“…A widely held candidate mechanism for these structures are Co-rotating Interaction Regions (Mullan 1984(Mullan ,1986, well studied in the solar wind. Another candidate are Rotational Modulations (RMs), as reported, e.g., by Massa et al (1995). The density contrasts for these larger structures are rather low (factors of at most a few), but they may contain large overall masses, e.g., 10 21−22 g for similar assumptions as above.…”

Section: Structures In Winds From Massive Starsmentioning

confidence: 66%

Stellar Winds in Massive X-ray Binaries

Kretschmar¹,

Martínez-Núñez

Bozzo

et al. 2016

Proc. IAU

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Abstract. Strong winds from massive stars are a topic of interest to a wide range of astrophysical fields. In High-Mass X-ray Binaries the presence of an accreting compact object on the one side allows to infer wind parameters from studies of the varying properties of the emitted X-rays; but on the other side the accretor's gravity and ionizing radiation can strongly influence the wind flow. Based on a collaborative effort of astronomers both from the stellar wind and the X-ray community, this presentation attempts to review our current state of knowledge and indicate avenues for future progress.

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Wind Variability of B Supergiants. I. The Rapid Rotator HD 64760 (B0.5 Ib)

Cited by 88 publications

References 0 publications

Analysis of far-UV data of central stars of planetary nebulae: Occurrence and variability of stellar winds

Analysis of far-UV data of central stars of planetary nebulae: Occurrence and variability of stellar winds

The variable stellar wind of Rigel probed at high spatial and spectral resolution

Stellar Winds in Massive X-ray Binaries

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