The long-period massive binary HD 54662 revisited

Mossoux, E.; Mahy, L.; Rauw, Grégor

doi:10.1051/0004-6361/201732095

Cited by 10 publications

(11 citation statements)

References 80 publications

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“…Boyajian et al (2007) classified this SB2 system as O6.5 V + O7-9.5 V. In GOSSS II we give a composite spectral type of O7 Vz var?. Le Bouquin et al (2017) have resolved this spectroscopic binary into their visual orbit and have been able to compute an orbit with a period of 2103.3 d, a value that agrees well with the previous value quoted in GOSSS II based on OWN data (2119 d) and with the more recent determination by Mossoux et al (2018) of 2103.4 d. According to Tetzlaff et al (2011) it is a runaway star based on its radial velocity (we did not detect it in Maíz Apellániz et al 2018b because its proper motion does not deviate significantly from the average values for O stars in that direction of the Galaxy). It has no entry in the WDS catalog and appears single in our AstraLux images.…”

Section: Orion-monocerossupporting

confidence: 83%

MONOS: Multiplicity Of Northern O-type Spectroscopic systems

Apellániz

Paez

Negueruela

et al. 2019

A&A

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Context. Multiplicity in massive stars is key to understanding the chemical and dynamical evolution of galaxies. Among massive stars, those of O type play a crucial role due to their high masses and short lifetimes. Aims. MONOS (Multiplicity Of Northern O-type Spectroscopic systems) is a project designed to collect information and study O-type spectroscopic binaries with δ > −20 • . In this first paper we describe the sample and provide spectral classifications and additional information for objects with previous spectroscopic and/or eclipsing binary orbits. In future papers we will test the validity of previous solutions and calculate new spectroscopic orbits. Methods. The spectra in this paper have two sources: the Galactic O-Star Spectroscopic Survey (GOSSS), a project that obtains blueviolet R ∼ 2500 spectroscopy of thousands of massive stars, and LiLiMaRlin, a library of libraries of high-resolution spectroscopy of massive stars obtained from four different surveys (CAFÉ-BEANS, OWN, IACOB, and NoMaDS) and additional data from our own observing programs and public archives. We have also used lucky images obtained with AstraLux. Results. We present homogeneous spectral classifications for 92 O-type spectroscopic multiple systems and ten optical companions, many of them original. We discuss the visual multiplicity of each system with the support of AstraLux images and additional sources. For eleven O-type objects and for six B-type objects we present their first GOSSS spectral classifications. For two known eclipsing binaries we detect double absorption lines (SB2) or a single moving line (SB1) for the first time, to which we add a third system reported by us recently. For two previous SB1 systems we detect their SB2 nature for the first time and give their first separate spectral classifications, something we have also done for a third object just recently identified as a SB2. We also detect nine new astrometric companions and provide updated information on several others. We emphasize the results for two stars: for σ Ori AaAbB we provide spectral classifications for the three components with a single observation for the first time thanks to a lucky spectroscopy observation obtained close to the Aa,Ab periastron and for θ 1 Ori CaCb we add it to the class of Galactic Of?p stars, raising the number of its members to six. Our sample of O-type spectroscopic binaries contains more triple-or higher-order systems than double systems.

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Section: Orion-monocerossupporting

confidence: 83%

MONOS: Multiplicity Of Northern O-type Spectroscopic systems

Apellániz

Paez

Negueruela

et al. 2019

A&A

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“…First, we explore the consistency of the period previously found by us and those quoted in the literature. To search for periodicities, we used all the measured RVs (Table 2 and appendix) for the narrowlined component, and RVs available from the literature (Plaskett 1924;Garmany et al 1980;Stickland & Lloyd 2001;Mossoux et al 2018). We have used the MARMUZ code (Marraco & Muzzio 1980) and the Lomb-Scargle method (Scargle 1982), as implemented by NASA Exoplanet Archive Periodogram Service, 5 obtaining most probable values of 2092 and 2098 d, respectively, in very good agreement with previous findings.…”

Section: The New Spectroscopic Orbitsupporting

confidence: 56%

A new spectroscopic analysis of the massive O + O type binary HD 54662 AB

Barbá

Sabín-Sanjulián

Arias

et al. 2020

Monthly Notices of the Royal Astronomical Society

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HD 54662 AB is one of the three O + OB binaries known so far with orbital period longer than 1000 d, offering the opportunity to test scenarios of massive star formation and models of single stellar evolution. Here, we present a detailed study of this system based on new high-resolution spectra and data. A disentangling method is used to recover the individual spectra of the primary and secondary components, which are classified as O6.5 V(n)z and O7.5 Vz, respectively. Combining radial velocity measurements and astrometric data, a new absolute orbit with a period of 2113 ± 9 d and an eccentricity of 0.062 ± 0.008 is determined, confirming previous findings. However, absolute masses of 23.8 ± 1.1 M⊙ for the primary and 20.3 ± 1.1 M⊙ for the secondary are obtained, differing from previous determinations but in reasonable agreement with the spectral types of the stars. Primary and secondary components show remarkably different projected rotational velocities (160 and ≲40 $\rm km\, s^{-1}$ , respectively), which is probably related to the formation process of the binary. Contrary to previously interpretations, the star with broader spectral features is the most massive object in the system. Stellar and wind parameters of both stars are derived through quantitative spectroscopic analysis of the disentangled spectra using fastwind models, and they are consistent with the current calibrations for O-type stars. Evolutionary masses and ages are also computed with the bonnsai tool. Ages below 2.5 Ma are obtained, in agreement with the youth expected from their Vz nature.

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“…Then EMCEE has been more widely used in a series of astrophysical studies 7 . In particular, it has been used in some recent works on stellar spectroscopy and interferometry (see, e.g., Domiciano de Souza et al 2014;Sanchez-Bermudez et al 2017;Mossoux et al 2018;Bouchaud et al 2020).…”

Section: The Code Emcee: a Mcmc Implementationmentioning

confidence: 99%

Probing the weak wind phenomenon in Galactic O-type giants

Almeida

Marcolino

Bouret

et al. 2019

A&A

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Aims. Analyses of Galactic late O dwarfs (O8-O9.5V stars) raised the "weak wind problem": spectroscopic mass-loss rates (Ṁ) are up to two orders of magnitude lower than the theoretical values. We investigated the stellar and wind properties of Galactic late O giants (O8-O9.5III stars). These stars have luminosities log(L /L ) ∼ 5.2, which is the critical value (onset of weak winds) proposed in the literature. Methods. We performed a spectroscopic analysis of nine O8-O9.5III stars in the ultraviolet (UV) and optical regions using the model atmosphere code CMFGEN. Results. Stellar luminosities were adopted using calibrations from the literature. Overall, our model spectral energy distributions agree well with the observed ones considering parallaxes from the latest GAIA data release (DR2). The effective temperature derived from the UV region agrees well with the ones from the optical. As expected, the analysis of the Hertzsprung-Russell (HR) diagram shows that our sample is more evolved than late O dwarfs. From the UV region, we foundṀ ∼ 10 −8 − 10 −9 M yr -1 overall. This is lower by ∼ 0.9 − 2.3 dex than predicted values based on the (global) conservation of energy in the wind. The mass-loss rates predicted from first principles, based on the moving reversing layer theory, agree better with our findings, but it fails to match the spectroscopiċ M for the most luminous OB stars. The region of log(L /L ) ∼ 5.2 is critical for both sets of predictions in comparison with the spectroscopic mass-loss rates. CMFGEN models with the predictedṀ (the former one) fail to reproduce the UV wind lines for all the stars of our sample. We reproduce the observed Hα profiles of four objects with ourṀ derived from the UV. Hence, lowṀ values (weak winds) are favored to fit the observations (UV + optical), but discrepancies between the UV and Hα diagnostics remain for some objects. Conclusions. Our results indicate weak winds beyond the O8-9.5V class, since the region of log(L /L ) ∼ 5.2 is indeed critical to the weak wind phenomenon. Since O8-O9.5III stars are more evolved than O8-9.5V, evolutionary effects do not seem to play a role in the onset of the weak wind phenomenon. These findings support that theṀ (for low luminosity O stars) in use in the majority of modern stellar evolution codes must be severely overestimated up to the end of the H-burning phase. Further investigations must evaluate the consequences of weak winds in terms of physical parameters for massive stars (e.g., angular momentum and CNO surface abundances).

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The long-period massive binary HD 54662 revisited

Cited by 10 publications

References 80 publications

MONOS: Multiplicity Of Northern O-type Spectroscopic systems

MONOS: Multiplicity Of Northern O-type Spectroscopic systems

A new spectroscopic analysis of the massive O + O type binary HD 54662 AB

Probing the weak wind phenomenon in Galactic O-type giants

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