HD 161701, a chemically peculiar binary with a HgMn primary and an Ap secondary

González, J. F.; Saffe, C.; Castelli, F.; Hubrig, S.; Ilyin, I.; Schöller, M.; Carroll, T. A.; Leone, F.; Giarrusso, M.

doi:10.1051/0004-6361/201322327

Cited by 17 publications

(20 citation statements)

References 64 publications

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“…A field was claimed on the basis of a single marginal observation of HD 136504 by Hubrig et al (2009) and clearly detected by Shultz et al (2012); other data were taken from the paper by Shultz et al (2015) announcing the discovery of a field in the secondary star of this system and analysing the system. The magentic field of the secondary star in the HD 161701 system was discovered by Hubrig et al (2014), and their analysis of this system was described in more detail by González et al (2014). All data concerning BD-19 5044L are from the present paper.…”

Section: Discussionmentioning

confidence: 88%

BD-19 5044L: discovery of a short-period SB2 system with a magnetic Bp primary in the open cluster IC 4725

Landstreet¹,

Kochukhov²,

Alécian³

et al. 2017

A&A

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Context. Until recently almost nothing was known about the evolution of magnetic fields found in upper main sequence Ap/Bp stars during their long main sequence lifetime. We are thus studying magnetic Ap/Bp stars in open clusters in order to obtain observational evidence of how the properties of Ap/Bp magnetic stars, such as field strength and structure, evolve with age during the main sequence. One important aspect of this study is to search for the very rare examples of hot magnetic stars in short-period binary systems among magnetic cluster members. Aims. In this paper we characterize the object BD-19 5044L, which is both a member of the open cluster IC 4725 = M 25, and a short-period SB2 system containing a magnetic primary star. Methods. We have obtained a series of intensity and circular polarisation spectra distributed through the orbital and rotation cycles of BD-19 5044L with the ESPaDOnS spectropolarimeter at CFHT. From these data we determine the orbital and stellar properties of each component. Results. We find that the orbit of BD-19 5044L AB is quite eccentric (e = 0.477), with a period of 17.63 d. The primary is a magnetic Bp star with a variable longitudinal magnetic field, a polar field strength of ∼ 1400 G and a low obliquity, while the secondary is probably a hot Am star and does not appear to be magnetic. The rotation period of the primary (5.04 d) is not synchronised with the orbit, but the rotation angular velocity is close to being synchronised with the orbital angular velocity of the secondary at periastron, perhaps as a result of tidal interactions. Because this system is a member of IC 4725, the two stars have a common age of log t = 8.02 ± 0.05 dex. Conclusions. The periastron separation is small enough (about 12 times the radius of the primary star) that BD-19 5044L may be one of the very rare known cases of a tidally interacting SB2 binary system containing a magnetic Ap/Bp star.

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Section: Discussionmentioning

confidence: 88%

BD-19 5044L: discovery of a short-period SB2 system with a magnetic Bp primary in the open cluster IC 4725

Landstreet¹,

Kochukhov²,

Alécian³

et al. 2017

A&A

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“…The most natural explanation, then, would be the assumption that the secondary component is actually an Ap star. So far, HD 161701 is the only known case of a binary system formed by an Ap and an HgMn star 47 , 48 . However, while the secondary star is situated in the temperature regime of Ap stars, no hint of Ap-star-typical peculiarities are present in our spectroscopic material.…”

Section: Discussionmentioning

confidence: 99%

HD 66051, an eclipsing binary hosting a highly peculiar, HgMn-related star

Niemczura

Hümmerich

Castelli

et al. 2017

Sci Rep

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HD 66051 is an eclipsing system with an orbital period of about 4.75 d that exhibits out-of-eclipse variability with the same period. New multicolour photometric observations confirm the longevity of the secondary variations, which we interpret as a signature of surface inhomogeneities on one of the components. Using archival and newly acquired high-resolution spectra, we have performed a detailed abundance analysis. The primary component is a slowly rotating late B-type star (T eff = 12500 ± 200 K; log g = 4.0, v sin i = 27 ± 2 km s−1) with a highly peculiar composition reminiscent of the singular HgMn-related star HD 65949, which seems to be its closest analogue. Some light elements as He, C, Mg, Al are depleted, while Si and P are enhanced. Except for Ni, all the iron-group elements, as well as most of the heavy elements, and in particular the REE elements, are overabundant. The secondary component was estimated to be a slowly rotating A-type star (T eff ~ 8000 K; log g = 4.0, v sin i ~ 18 km s−1). The unique configuration of HD 66051 opens up intriguing possibilities for future research, which might eventually and significantly contribute to the understanding of such diverse phenomena as atmospheric structure, mass transfer, magnetic fields, photometric variability and the origin of chemical anomalies observed in HgMn stars and related objects.

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“…The atomic line list and laboratory data used in this work are basically those described in Castelli & Hubrig (2004), updated with specialized references as described in Sect. 7 of González et al (2014). Abundances were determined iteratively by fitting different metallic lines using the program SYNTHE.…”

Section: Stellar Parameters and Abundance Analysismentioning

confidence: 99%

KELT-17: a chemically peculiar Am star and a hot-Jupiter planet

Saffe

Miquelarena

Alacoria

et al. 2020

A&A

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Context. There is very little information to be found in the literature regarding the detection of planets orbiting chemically peculiar stars. Aims. Our aim is to determine the detailed chemical composition of the remarkable planet host star KELT-17. This object hosts a hot-Jupiter planet with 1.31 MJup detected by transits, and it is one of the more massive and rapidly rotating planet hosts seen to date. We set out to derive a complete chemical pattern for this star, in order to compare it with those of chemically peculiar stars. Methods. We carried out a detailed abundance determination in the planet host star KELT-17 via spectral synthesis. Stellar parameters were estimated iteratively by fitting Balmer line profiles and imposing the Fe ionization balance using the SYNTHE program together with plane-parallel ATLAS12 model atmospheres. Specific opacities for an arbitrary composition and microturbulence velocity vmicro were calculated through the opacity sampling (OS) method. The abundances were determined iteratively by fitting synthetic spectra to metallic lines of 16 different chemical species using SYNTHE. The complete chemical pattern of KELT-17 was compared to the recently published average pattern of Am stars. We estimated the stellar radius using two methods: a) comparing the synthetic spectral energy distribution with the available photometric data and the Gaia parallax, and b) using a Bayesian estimation of stellar parameters using stellar isochrones. Results. We found over-abundances of Ti, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, and Ba, together with subsolar values of Ca and Sc. Notably, the chemical pattern agrees with those recently published for Am stars, making KELT-17 the first exoplanet host whose complete chemical pattern is unambiguously identified with this class. The stellar radius derived by two different methods agrees to each other and with those previously obtained in the literature.

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HD 161701, a chemically peculiar binary with a HgMn primary and an Ap secondary

Cited by 17 publications

References 64 publications

BD-19 5044L: discovery of a short-period SB2 system with a magnetic Bp primary in the open cluster IC 4725

BD-19 5044L: discovery of a short-period SB2 system with a magnetic Bp primary in the open cluster IC 4725

HD 66051, an eclipsing binary hosting a highly peculiar, HgMn-related star

KELT-17: a chemically peculiar Am star and a hot-Jupiter planet

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