Mass loss rate determination of southern OB stars

Benaglia, P.; Cappa, C. E.; Koribalski, B. S.

doi:10.1051/0004-6361:20010617

Cited by 26 publications

(36 citation statements)

References 50 publications

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“…However, the available kinematic and photometric data do not indicate cluster or association membership for CPD−47 2963. The origin of the magnetic field in this star probably differs from those of other magnetic O-type stars, because non-thermal radio emission, which is frequently observed in binary systems with colliding winds, was detected by Benaglia et al (2001). On the other hand, the membership of CPD−47 2963 in a binary or multiple system has not yet been investigated.…”

Section: Observations and Resultsmentioning

confidence: 85%

Exploring the origin of magnetic fields in massive stars: a survey of O-type stars in clusters and in the field

Hubrig

Schöller

Kharchenko

et al. 2011

A&A

100

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Context. Although the effects of magnetic fields in massive stars have been found to be substantial by recent models and observations, the magnetic fields of only a small number of massive O-type stars have so far been investigated. Additional observations are of the utmost importance to constraining the conditions that are conducive to magnetic fields and to determine the first trends about their occurrence rate and field strength distribution. Aims. To investigate statistically whether magnetic fields in massive stars are ubiquitous or appear only in stars with a specific spectral classification, certain ages, or in a special environment, we acquired 41 new spectropolarimetric observations for 36 stars. Among the observed sample, roughly half of the stars are probable members of clusters at different ages, whereas the remaining stars are field stars not known to belong to any cluster or association. Methods. Spectropolarimetric observations were obtained during three different nights using the low-resolution spectropolarimetric mode of FORS 2 (FOcal Reducer low dispersion Spectrograph) mounted on the 8-m Antu telescope of the VLT. To assess the membership in open clusters and associations, we used astrometric catalogues with the highest quality kinematic and photometric data currently available. Results. A field at a significance level of 3σ was detected in ten O-type stars. The strongest longitudinal magnetic fields were measured in two Of?p stars: B z = −381 ± 122 G for CPD−28 2561 and B z = −297 ± 62 G for HD 148937, the latter of which had previously been detected by ourselves as magnetic. The observations of HD 148937 obtained on three different nights indicate that the magnetic field is slightly variable. Our new measurements support our previous conclusion that large-scale organized magnetic fields with polar field strengths in excess of 1 kG are not widespread among O-type stars. Among the stars with a detected magnetic field, only one star, HD 156154, belongs to an open cluster at high membership probability. According to previous kinematic studies, four magnetic O-type stars in the sample are well-known candidate runaway stars.

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Section: Observations and Resultsmentioning

confidence: 85%

Exploring the origin of magnetic fields in massive stars: a survey of O-type stars in clusters and in the field

Hubrig

Schöller

Kharchenko

et al. 2011

A&A

100

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“…According to Walborn et al (2010), CPD−47 2963 belongs to the Ofc category, which consists of normal spectra with C iii λλ 4647-4650-4652 emission lines of comparable intensity to those of the Of defining lines N iii λλ 4634-4640-4642. The origin of the magnetic field in this star probably differs from those of other magnetic O-type stars, because non-thermal radio emission, which is frequently observed in binary systems with colliding winds, was detected by Benaglia et al (2001). On the other hand, the membership of CPD−47 2963 to a binary or multiple system has not yet been investigated.…”

Section: Cpd−47 2963mentioning

confidence: 85%

Exploring the origin of magnetic fields in massive stars

Hubrig

Schöller

Ilyin

et al. 2013

A&A

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Context. Theories on the origin of magnetic fields in massive stars remain poorly developed, because the properties of their magnetic field as function of stellar parameters could not yet be investigated. Additional observations are of utmost importance to constrain the conditions that are conducive to magnetic fields and to determine first trends about their occurrence rate and field strength distribution. Aims. To investigate whether magnetic fields in massive stars are ubiquitous or appear only in stars with a specific spectral classification, certain ages, or in a special environment, we acquired 67 new spectropolarimetric observations for 30 massive stars. Among the observed sample, roughly one third of the stars are probable members of clusters at different ages, whereas the remaining stars are field stars not known to belong to any cluster or association. Methods. Spectropolarimetric observations were obtained during four different nights using the low-resolution spectropolarimetric mode of FOcal Reducer low dispersion Spectrograph (FORS 2) mounted on the 8-m Antu telescope of the VLT. Furthermore, we present a number of follow-up observations carried out with the high-resolution spectropolarimeters SOFIN mounted at the Nordic Optical Telescope (NOT) and HARPS mounted at the ESO 3.6 m between 2008 and 2011. To assess the membership in open clusters and associations, we used astrometric catalogues with the highest quality kinematic and photometric data currently available. Results. The presence of a magnetic field is confirmed in nine stars previously observed with FORS

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“…The star was observed in three opportunities with ATCA at 3 and 6 cm, with flux density variations (see Benaglia et al 2001, and Table 3). …”

Section: Hd 124314mentioning

confidence: 99%

Radio Detection of Colliding Wind Binaries

Benaglia

Koribalski

Colombo

2006

Publ. – Astron. Soc. Aust

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Four massive, early-type stars, three of which are confirmed binaries, have been observed with the Australia Telescope Compact Array at 1.4, 2.4, 4.8, and 8.6 GHz. The earliest star cataloged so far, HD 93129A, was also observed at 17.8 and 24.5 GHz. Here we present an analysis of the spectra as well as the structure of the stellar systems. All four spectra show clear evidence of non-thermal emission, indicative of a binary system with a colliding wind region. We discuss the magnetic field of the emitting region of HD 93129A and make predictions on the radiation at high energies. Archive X-ray observations towards the target sources are also investigated and interpreted in the light of the non-thermal emission detected.

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Mass loss rate determination of southern OB stars

Cited by 26 publications

References 50 publications

Exploring the origin of magnetic fields in massive stars: a survey of O-type stars in clusters and in the field

Exploring the origin of magnetic fields in massive stars: a survey of O-type stars in clusters and in the field

Exploring the origin of magnetic fields in massive stars

Radio Detection of Colliding Wind Binaries

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