Searching for lambda Boo stars in binary systems

Abstract

Our goal is to find new candidate lambda Boo stars that belong to binary systems. A detailed abundance determination of some candidates could confirm their true lambda Boo nature, while the composition of eventual late-type companions could be used as a proxy for the initial composition of the lambda Boo stars. Results. We obtained a group of 19 newly identified binary systems which contain a candidate lambda Boo star, allowing to duplicate the number of lambda Boo stars currently known in multiple systems. This important group could be used in further studies of lambda Boo stars. For the first time, we performed a detailed abundance analysis of three of these binary systems which includes a candidate lambda Boo star and a late-type companion. We confirmed the true lambda Boo nature of the three early-type stars (HD 87304, HD 98069 and HD 153747), and obtained mostly a solar-like composition for their late-type components. Adopting as a proxy the late-type stars, we showed that the three lambda Boo stars were initially born with a solar-like composition. This is an important constraint for any scenario trying to explain the origin of lambda Boo stars. Also, the solar-like composition of the late-type stars supports the idea that lambda Boo stars are Population I objects, however, we caution that other explanations are also possible. Conclusions. We performed, for the first time, a detailed abundance analysis of binary systems including a lambda Boo star and a late-type companion. We obtained a solid indication that lambda Boo stars born from a solar-like composition and established an important constraint to test formation models of lambda Boo stars.[abridged]

11 pages, 9 figures, 9 tables, A&A accepted

References in corpus (30)

• The chemical composition of the Sun
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Basic physical parameters of a selected sample of evolved stars
• A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
• The Sixth Data Release of the Radial Velocity Experiment (RAVE) -- II: Stellar Atmospheric Parameters, Chemical Abundances and Distances
• Fingerprints of giant planets in the photospheres of Herbig stars
• Finding binaries from phase modulation of pulsating stars with Kepler: V. Orbital parameters, with eccentricity and mass-ratio distributions of 341 new binaries
• Signatures of rocky planet engulfment in HAT-P-4. Implications for chemical tagging studies
• The lambda Bootis phenomenon: interaction between a star and a diffuse interstellar cloud
• Theoretical analysis of the atmospheres of CP stars. Effects of the individual abundance patterns
• Gaia's view of the $\lambda$ Boo star puzzle
• The abundance pattern of the lambda Bootis stars
• An evaluation of the membership probability of 212 $\lambda$ Boo stars: I. A Catalogue
• Revisiting the pre-main-sequence evolution of stars II. Consequences of planet formation on stellar surface composition
• Metallicity and age effects on lithium depletion in solar analogues
• On the Period-Luminosity-Colour-Metallicity relation and the pulsational characteristics of lambda Bootis type stars
• Infrared Emission by Dust Around lambda Bootis Stars: Debris Disks or Thermally Emitting Nebulae?
• Chemical analysis of early-type stars with planets
• Lambda Boo Abundance Patterns: Accretion from Orbiting Sources
• High-precision analysis of binary stars with planets. I. Searching for condensation temperature trends in the HD 106515 system
• The Pulsation Properties of $\lambda$ Bootis Stars I. The Southern TESS Sample
• The Discovery of lambda Bootis Stars -- The Southern Survey II
• Using non-solar-scaled opacities to derive stellar parameters. Toward high-precision parameters and abundances
• HD 210111: a new lambda Bootis type SB system
• Disentangling the origin of chemical differences using GHOST
• KELT-17: a chemically peculiar Am star and a hot-Jupiter planet
• Assessing the processes behind planet engulfment and its imprints
• Investigating the possible connection between lambda Bootis stars and intermediate Population II type stars
• Testing the accretion scenario of lambda Boo stars
• Are Am stars and hot-Jupiter planets related?

Cited by in corpus (2)

• Discovery of lambda Boo stars in open clusters
• Drifters on the edge of town: $\lambda$ Boötis stars in clusters