THE MULTIPLICITY OF MASSIVE STARS: A HIGH ANGULAR RESOLUTION SURVEY WITH THE<i>HST</i>FINE GUIDANCE SENSOR

Aldoretta, Emily J.; Caballero-Nieves, S. M.; Gies, Douglas R.; Nelan, Edmund; Wallace, Debra J.; Hartkopf, William I.; Henry, Todd J.; Jao, Wei-Chun; Apellániz, J. Maíz; Mason, Brian D.; Moffat, A. F. J.; Norris, R. P.; Richardson, Noel D.; Williams, Stephen J.

doi:10.1088/0004-6256/149/1/26

Cited by 91 publications

(109 citation statements)

References 71 publications

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“…For instance, the primary of HD 93146 A is the earliest star in our sample and has a long period of 1131.4 d. Both this star and HD 123056, another star that probably has a period of 1314 d, might be suitable targets for interferometry. HD 123056 was already observed by Aldoretta et al (2015), but not separated; higher resolution than 10 mas is probably needed. Also in the case of HD 93146 A, high resolution is necessary; at a distance of ≈ 3.0 kpc its semi-major axis might be of the order of 2.5 mas.…”

Section: Discussionmentioning

confidence: 99%

Physical properties of seven binary and higher-order multiple OB systems

Mayer

Harmanec

Chini

et al. 2017

A&A

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Analyses of multi-epoch, high-resolution (R ∼ 50000) optical spectra of seven early-type systems provided various important new insights with respect to their multiplicity. For HD 93146 A, which was hitherto assumed to be SB1, lines of a secondary component could be discerned. HD 123056 turns out to be a multiple system consisting of a high-mass component A (≈ O8.5) displaying a broad He ii 5411 Å feature with variable radial velocity, and of an inner pair B (≈ B0) with double He i lines. The binary HD 164816 was revisited and some of its system parameters were improved. In particular, we determined its systemic velocity to be −7 km s −1 , which coincides with the radial velocity of the cluster NGC 6530. This fact, together with its distance, suggests the cluster membership of HD 164816. The OB system HD 318015 (V1082 Sco) belongs to the rare class of eclipsing binaries with a supergiant primary (B0.5/0.7). Our combined orbital and light-curve analysis suggests that the secondary resembles an O9.5 III star. Our results for a limited sample corroborate the findings that many O stars are actually massive multiple systems.

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Section: Discussionmentioning

confidence: 99%

Physical properties of seven binary and higher-order multiple OB systems

Mayer

Harmanec

Chini

et al. 2017

A&A

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“…Since the 9 Sgr system is only partially resolved with the FGS, there is an ambiguity between the separation ρ and the optical brightness ratio F 1 /F 2 , and a four-fold ambiguity on the position angle θ. Aldoretta et al (2015) reported ρ min = (18.5 ± 1.9) mas assuming a brightness ratio of unity. Assuming F 1 /F 2 = 1.5 (Paper II, Sana et al 2014), Eq.…”

Section: New Orbital Solutionmentioning

confidence: 99%

“…They found ρ = (4.95 ± 1.05) mas, θ = (242.22 ± 19.95) • and ∆m H = 0.45 ± 0.05 (or F 1 /F 2 = 1.51 ± 0.07, in excellent agreement with our determination of the optical brightness ratio F 1 /F 2 in the range 1.0−1.5 in Paper II). Aldoretta et al (2015) reported an observation taken on 2008.1920 (φ = 0.397) with the Fine Guidance Sensor (FGS) onboard the HST. Since the 9 Sgr system is only partially resolved with the FGS, there is an ambiguity between the separation ρ and the optical brightness ratio F 1 /F 2 , and a four-fold ambiguity on the position angle θ.…”

Section: New Orbital Solutionmentioning

confidence: 99%

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Testing the theory of colliding winds: the periastron passage of 9 Sagittarii

Rauw

Blomme

Nazé

et al. 2016

A&A

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Context. The long-period, highly eccentric O-star binary 9 Sgr, known for its non-thermal radio emission and its relatively bright X-ray emission, went through its periastron in 2013. Aims. Such an event can be used to observationally test the predictions of the theory of colliding stellar winds over a broad range of wavelengths. Methods. We conducted a multi-wavelength monitoring campaign of 9 Sgr around the 2013 periastron. In this paper, we focus on X-ray observations and optical spectroscopy. Results. The optical spectra allow us to revisit the orbital solution of 9 Sgr and to refine its orbital period to 9.1 years. The X-ray flux is maximum at periastron over all energy bands, but with clear differences as a function of energy. The largest variations are observed at energies above 2 keV, whilst the spectrum in the soft band (0.5−1.0 keV) remains mostly unchanged, indicating that it arises far from the collision region, in the inner winds of the individual components. The level of the hard emission at periastron clearly deviates from the 1/r relation expected for an adiabatic wind-interaction zone, whilst this relation seems to hold at the other phases that are covered by our observations. The spectra taken at phase 0.946 reveal a clear Fe xxv line at 6.7 keV, but no such line is detected at periastron (φ = 0.000), although a simple model predicts a strong line that should be easily visible in the data. Conclusions. The peculiarities of the X-ray spectrum of 9 Sgr could reflect the effect of radiative inhibition as well as a phasedependent efficiency of particle acceleration on the shock properties.

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“…Furthermore, Tokovinin et al (2010) obtained Speckle interferometry images of HD 64315 (see Figure 12 in the mentioned study) suggesting that the system may consist of three visual components in a linear configuration (Tokovinin et al 2010). The fit of the x-axis scan with two components is marginal, but experiments with three component made little or no improvement (Aldoretta et al 2015). Therefore the two visual components resolved represent two systems of comparable (but not equal) brightness that are either in a very wide orbit or are not bound.…”

Section: Interferometry and Parallaxmentioning

confidence: 89%

The massive multiple system HD 64315

Lorenzo

Negueruela

Vilardell

et al. 2017

A&A

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Context. The O6 Vn star HD 64315 is believed to belong to the star-forming region known as NGC 2467, but previous distance estimates do not support this association. Moreover, it has been identified as a spectroscopic binary, but existing data support contradictory values for its orbital period. Aims. We explore the multiple nature of this star with the aim of determining its distance, and understanding its connection to NGC 2467. Methods. A total of 52 high-resolution spectra have been gathered over a decade. We use their analysis, in combination with the photometric data from All Sky Automated Survey and Hipparcos catalogues, to conclude that HD 64315 is composed of at least two spectroscopic binaries, one of which is an eclipsing binary. We have developed our own program to fit four components to the combined line shapes. Once the four radial velocities were derived, we obtained a model to fit the radial-velocity curves using the Spectroscopic Binary Orbit Program (SBOP). We then implemented the radial velocities of the eclipsing binary and the light curves in the Wilson-Devinney code iteratively to derive stellar parameters for its components. We were also able to analyse the non-eclipsing binary, and to derive minimum masses for its components which dominate the system flux. Results. HD 64315 contains two binary systems, one of which is an eclipsing binary. The two binaries are separated by ∼ 0.09 arcsec (or ∼ 500 AU) if the most likely distance to the system, ∼ 5 kpc, is considered. The presence of fainter companions is not excluded by current observations. The non-eclipsing binary (HD 64315 AaAb) has a period of 2.70962901 ± 0.00000021 d. Its components are hotter than those of the eclipsing binary, and dominate the appearance of the system. The eclipsing binary (HD 64315 BaBb) has a shorter period of 1.0189569 ± 0.0000008 d. We derive masses of 14.6 ± 2.3 M ⊙ for both components of the BaBb system. They are almost identical; both stars are overfilling their respective Roche lobes, and share a common envelope in an overcontact configuration. The non-eclipsing binary is a detached system composed of two stars with spectral types around O6 V with minimum masses of 10.8 M ⊙ and 10.2 M ⊙ , and likely masses ≈ 30 M ⊙ . Conclusions. HD 64315 provides a cautionary tale about high-mass star isolation and multiplicity. Its total mass is likely above 90 M ⊙ , but it seems to have formed without an accompanying cluster. It contains one the most massive overcontact binaries known, a likely merger progenitor in a very wide multiple system.

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THE MULTIPLICITY OF MASSIVE STARS: A HIGH ANGULAR RESOLUTION SURVEY WITH THEHSTFINE GUIDANCE SENSOR

Abstract: We present the results of an all-sky survey made with the Fine Guidance Sensor on Hubble Space Telescope to search for angularly resolved binary systems among the massive stars. The sample of 224 stars is comprised mainly of Galactic

Cited by 91 publications

References 71 publications

Physical properties of seven binary and higher-order multiple OB systems

Physical properties of seven binary and higher-order multiple OB systems

Testing the theory of colliding winds: the periastron passage of 9 Sagittarii

The massive multiple system HD 64315

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