Radial velocities of 368 helium stars.

Frost, Edwin B.; Barrett, Storrs B.; Struve, Otto

doi:10.1086/142986

Cited by 69 publications

(54 citation statements)

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“…HD 28446 was first suggested to be a spectroscopic binary by Frost et al (1926). In this context, Plaskett & Pearce (1931) claimed that HD 28446 is an SB2 with a large velocity amplitude A56, page 23 of 57 A&A 603, A56 (2017) (K ∼ 140 km s −1 ).…”

Section: C10 Hd 28446amentioning

confidence: 99%

Chemical abundances of fast-rotating massive stars

Cazorla

Morel

Nazé

et al. 2017

A&A

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Aims. Recent observations have challenged our understanding of rotational mixing in massive stars by revealing a population of fastrotating objects with apparently normal surface nitrogen abundances. However, several questions have arisen because of a number of issues, which have rendered a reinvestigation necessary; these issues include the presence of numerous upper limits for the nitrogen abundance, unknown multiplicity status, and a mix of stars with different physical properties, such as their mass and evolutionary state, which are known to control the amount of rotational mixing. Methods. We have carefully selected a large sample of bright, fast-rotating early-type stars of our Galaxy (40 objects with spectral types between B0.5 and O4). Their high-quality, high-resolution optical spectra were then analysed with the stellar atmosphere modelling codes DETAIL/SURFACE or CMFGEN, depending on the temperature of the target. Several internal and external checks were performed to validate our methods; notably, we compared our results with literature data for some well-known objects, studied the effect of gravity darkening, or confronted the results provided by the two codes for stars amenable to both analyses. Furthermore, we studied the radial velocities of the stars to assess their binarity.Results. This first part of our study presents our methods and provides the derived stellar parameters, He, CNO abundances, and the multiplicity status of every star of the sample. It is the first time that He and CNO abundances of such a large number of Galactic massive fast rotators are determined in a homogeneous way.

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Section: C10 Hd 28446amentioning

confidence: 99%

Chemical abundances of fast-rotating massive stars

Cazorla

Morel

Nazé

et al. 2017

A&A

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“…Genderen et al (1989), on the other hand, claim that the magnitude of this star is constant with an accuracy up to a few mmag. Radial velocities (RVs) of the star were measured for the first time by Frost et al (1926) who discovered its variability. Struve & Titus (1944) obtained a dense series of RV observations, but did not search for variability.…”

Section: Introductionmentioning

confidence: 99%

Θ¹ Orionis C - A triple system?

Lehmann

Vitrichenko

Бычков

et al. 2010

A&A

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Context. As the brightest star in the Trapezium cluster, Θ 1 Ori C is the youngest and nearest to us among O-stars. It is considered to be a multiple system where the main component is an oblique magnetic rotator. Aims. Here, we aim at explaining the structure of the Θ 1 Ori C system. We check for a new hypothesis about the presence of a third component and try to derive the corresponding orbital solutions and the absolute masses of the components. Methods. We measured new radial velocities (RVs) of Θ 1 Ori C and and combined them with data from literature. For the analysis, we used multiple frequency search and iterative calculations of orbits based on the method of differential corrections, applying successive prewhitening to the data in both methods. Results are compared with those obtained from speckle observations. Results. We detected the impact of the known distant companion in the RVs of the primary and can now calculate a spectroscopic orbital solution that is consistent with the observed astrometric positions. We find evidence that Θ 1 Ori C is at least a triple system consisting of the primary, the known astrometric companion in a wide eccentric orbit with a period of 11 yr, and a second companion in a close eccentric orbit with a period of 61. d 5. We assign the additionally found period of 15. d 4 d to the rotation of the primary, which is in a 1:4 resonance with the close orbit. Derived masses are 31 M for the primary, 12 M for the distant, and 1 M for the close companion.

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“…[Docobo & Ling 1998]).ÈThis binary has been extensively studied using a number of di †erent techniques. Radial velocity measurements have been reported by Henroteau (1921), Frost, Barrett, & Struve (1926), Campbell & Moore (1928), Petrie (1958), Wilson (1963), Evans (1978), and Abt & Levy (1978), and the IUE-ULDA access guide (Wamsteker 1989) lists two LWR and two SWR measurements made in 1978 November. The photometric data all agree remarkably : the observations published between 1963 and 1971 (Crawford 1963 ;Haggkvist & Oja 1966 ;Johnson et al 1966 ;Crawford, Barnes, & Golson 1971) A full revolution has been completed since the binary was discovered by Burham (1881.86) with the 12 inch (30 cm) telescope at Mount Hamilton.…”

Section: Methodsmentioning

confidence: 91%