A new study of the spectroscopic binary 7 Vul with a Be star primary

Harmanec, P.; Lipták, J.; Koubský, P.; Božić, H.; Labadie-Bartz, Jonathan; Šlechta, M.; Yang, S.; Harmanec, A.

doi:10.1051/0004-6361/202037964

Cited by 15 publications

(17 citation statements)

References 38 publications

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“…Therefore, the star rotates near its break‐up velocity, and the minimum possible inclination of the stellar rotation axis is i = 56° (respectively as low as i = 34° considering the 1 σ uncertainty of v crit ). The obtained value of v sin( i ) is in good agreement with those obtained by others earlier, for example, 420 ± 8 km s −1 by Harmanec (), ∼415 km s −1 by Walker (), or 400 ± 20 km s −1 by Reid et al (), while it deviates at the 2 σ level from the v sin( i ) values reported by Cazorla et al () (378 ± 15 km s −1 ), van Belle () (∼385 km s −1 ), and Howarth et al () (372 ± 30 km s −1 ). Zorec et al () and Simón‐Díaz & Herrero () obtained even smaller values of 344 ± 34 and ∼319 km s −1 , respectively.…”

Section: Resultssupporting

confidence: 91%

The radial and rotational velocity of ζ Ophiuchi

Zehe¹,

Mugrauer²,

Neuhäuser³

et al. 2018

Astron Nachr

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We present the results of our spectroscopic monitoring campaign of Oph, carried out at the University observatory Jena with the spectrograph FLECHAS between July 2015 and September 2016. The main aim of the project was to determine the radial velocity of the star precisely, as a wide range of radial velocity measurements of Oph are given in the literature. Besides the proper motion and parallax, the radial velocity is an important input parameter for the calculation of the space motion of the star. Oph is considered to be a runaway star and potential former companion of the progenitor star of the pulsar PSR J1932+1059, both of which may have been located in a binary system and were then released during a supernova explosion about 1 Myr ago in the Upper Scorpius OB association. For the conclusion that the pulsar and Oph could have been at the same place, a radial velocity of −9.0 km s −1 for Oph was used in the literature. By analyzing the hydrogen and helium lines in 48 FLECHAS spectra, we determined the radial velocity of Oph to be 12.2 ± 3.3 km s −1 and the projected rotational velocity to be 432 ± 16 km s −1 with no indication of variability.

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Section: Resultssupporting

confidence: 91%

The radial and rotational velocity of ζ Ophiuchi

Zehe¹,

Mugrauer²,

Neuhäuser³

et al. 2018

Astron Nachr

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show abstract

“…Similar conclusions were obtained by Vieira et al (2017). A correlation between Hα emission and visual magnitude strength has been proposed by Harmanec (1983) and more recently supported by Sigut & Patel (2013), who interpreted the correlation in terms of disks that grow in size and/or density with time. The Be star outbursts are presently being modeled within the theory of viscous decretion disks controlled by variable mass loss Ṁ and parameterized through the viscosity parameter α (Haubois et al 2012;Rímulo et al 2015).…”

Section: Introductionsupporting

confidence: 82%

Multi-epoch L-band Spectroscopy of the Be Star μ Centauri Prior to Outburst

Aguayo

Mennickent

Granada

et al. 2018

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With the aim of contributing to the understanding of the disk formation process in Be stars, we pursued a one-year spectroscopic observing campaign of the Be star μ Centauri in the L-band, using VLT/ISAAC. We present the nine near-IR spectra we obtained in an epoch of relative photometric quiescence prior to an outburst of ΔV=0.4 magnitude. Visual estimates during the epoch of our L-band spectroscopy are also presented for the first time, together with the unpublished complete visual light curve between the years 1998 and 2014. We observe significant and monotonic changes in emission line strength of Bracket-α and Pfund-γ lines relative to Humphreys lines, and also in the continuum slope. We interpret these observed changes in terms of important changes to the column density of the line emitting regions, moving from an optically thin to an optically thick stage just prior to a major outburst. For each observing date, we provide estimates for the column density and relative extension of the line emitting region. If the changes observed toward the end of our observing campaign were related to mass-loss changes from the central star, they would correspond to an increase in a factor of two in the mass of the disk in the innermost region. If related to the visual outburst observed one month later, the variability observed in our spectra would be the first detection of the early disk formation process in the L-band.

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“…Such binaries (with yet unseen companions) may also be found among the mid/late type B stars (e.g. 7 Vul, B5Ve, Harmanec et al 2020). These and similar systems with known orbital periods are included in the target list, where Polstar observations can be scheduled to cover the orbital phases.…”

Section: The Known Be+sdo Populationmentioning

confidence: 99%

Ultraviolet Spectropolarimetry with Polstar: on the origin of rapidly rotating B stars

Jones¹,

Labadie-Bartz²,

Nazé³

et al. 2021

Preprint

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The proposed MIDEX mission, Polstar, will provide high resolution UV spectroscopy and spectropolarimetry and offers a unique opportunity to study massive stars in this wavelength range with unprecedented detail. We demonstrate that these observations will provide critical new knowledge of several types of massive stars (specifically the B-emission stars and the Bn stars). We will determine accurate stellar parameters including their rotation rates and variation of surface temperature associated with stellar oblateness. Our work will allow us to detect binary companions and determine binary orbital properties. Binary population synthesis predictions will allow us to determine the fraction of these stars that are spun up due to binary interaction compared to single star evolution. These rapidly rotating stars have the potential to probe mass loss and the mixing of chemical elements which affects their evolution and ultimately the evolution of their surroundings.

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A new study of the spectroscopic binary 7 Vul with a Be star primary

Cited by 15 publications

References 38 publications

The radial and rotational velocity of ζ Ophiuchi

The radial and rotational velocity of ζ Ophiuchi

Multi-epoch L-band Spectroscopy of the Be Star μ Centauri Prior to Outburst

Ultraviolet Spectropolarimetry with Polstar: on the origin of rapidly rotating B stars

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