Interferometric Detection and Orbit Modeling of the Subcomponent in the Hot-dust System $\kappa$ Tuc A: A Low-mass Star on an Eccentric Orbit in a Hierarchical-quintuple System

Abstract

The system $\kappa$ Tuc A is part of a hierarchical-quintuple system and is a prime target for studies of hot-exozodiacal dust, because a time-variable near-infrared excess has been detected. We observed the system with the Multi Aperture mid-Infrared Spectroscopic Experiment (MATISSE) and GRAVITY at the Very Large Telescope Interferometer, and detected the stellar companion to the primary $\kappa$ Tuc Aa that was previously inferred by astrometry, $\kappa$ Tuc Ab. Its $L$-band flux ratio to the primary is 1.32% and its signature in the MATISSE closure phases is mostly smaller than +/- 2°, which makes $\kappa$ Tuc Ab the highest-contrast companion ever detected with MATISSE closure phases. We verified with GRAVITY that relative astrometry with milliarcsecond precision can be retrieved from MATISSE closure phases. Using multiple epochs of observations, we obtain a full orbital solution for $\kappa$ Tuc Ab. Its orbit has an eccentricity of 0.94 and a semi-major axis of 4.8au. The orbit of $\kappa$ Tuc Ab and the orbit of the wider separation companion $\kappa$ Tuc B are mutually inclined. Based on the measured flux ratio of $\kappa$ Tuc Ab to Aa and their dynamical mass, we estimate the spectral type of $\kappa$ Tuc Ab to be M3.5V to M4.5V. While the then unknown star $\kappa$ Tuc Ab might have caused the putative detection of hot-exozodiacal dust around $\kappa$ Tuc Aa in 2012 and 2014, this cannot be for the detection in 2019, giving rise to an intriguing system architecture. This motivates studies investigating the interplay of the low-mass star on an eccentric orbit, the hot-exozodiacal dust, and a possible planetesimal reservoir.

20 pages, 5 figures

References in corpus (92)

• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Gaia mission
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Gaia Data Release 3: Summary of the content and survey properties
• Validation of the new Hipparcos reduction
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• The SIMBAD astronomical database
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• The VizieR database of Astronomical Catalogues
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• Parallel Tempering: Theory, Applications, and New Perspectives
• Gaia Early Data Release 3: The astrometric solution
• First Light for GRAVITY: Phase Referencing Optical Interferometry for the Very Large Telescope Interferometer
• SPHERE: the exoplanet imager for the Very Large Telescope
• PIONIER: a 4-telescope visitor instrument at VLTI
• Debris Disks: Structure, Composition, and Variability
• Dynamic temperature selection for parallel-tempering in Markov chain Monte Carlo simulations
• Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure
• The Hipparcos-Gaia Catalog of Accelerations
• The Solar Neighborhood XXXVII: The Mass-Luminosity Relation for Main Sequence M Dwarfs
• Dust Dynamics, Surface Brightness Profiles, and Thermal Spectra of Debris Disks: The Case of AU Mic
• New Debris Disks Around Young, Low Mass Stars Discovered With The Spitzer Space Telescope
• Asteroid Belts in Debris Disk Twins: VEGA and FOMALHAUT
• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• orbitize!: A Comprehensive Orbit-fitting Software Package for the High-contrast Imaging Community
• The Collisional Evolution of Debris Disks
• Circumstellar material in the Vega inner system revealed by CHARA/FLUOR
• Where Are The M Dwarf Disks Older Than 10 Million Years?
• Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY
• Analysis of the Herschel DEBRIS Sun-like star sample
• A near-infrared interferometric survey of debris disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR
• Gaia DR3 astrometric orbit determination with Markov Chain Monte Carlo and Genetic Algorithms. Systems with stellar, substellar, and planetary mass companions
• Pseudomagnitudes and Differential Surface Brightness: Application to the apparent diameter of stars
• A near-infrared interferometric survey of debris-disc stars. IV. An unbiased sample of 92 southern stars observed in H-band with VLTI/PIONIER
• Dynamical evolution of an eccentric planet and a less massive debris disc
• Binaries Among Debris Disk Stars
• Hot exozodiacal dust resolved around Vega with IOTA/IONIC
• The GRAVITY fringe tracker
• An interferometric study of the Fomalhaut inner debris disk. III. Detailed models of the exozodiacal disk and its origin
• A near-infrared interferometric survey of debris-disc stars. V. PIONIER search for variability
• Searching for faint companions with VLTI/PIONIER. I. Method and first results
• An independent determination of Fomalhaut b's orbit and the dynamical effects on the outer dust belt
• A catalogue of stellar diameters and fluxes for mid-infrared interferometry
• The cold origin of the warm dust around epsilon Eridani
• Collisional modelling of the AU Microscopii debris disc
• Dust in the inner regions of debris disks around A stars
• Observations, Modeling and Theory of Debris Disks
• Stellar Multiplicity and Debris Disks: An Unbiased Sample
• Inner mean-motion resonances with eccentric planets: A possible origin for exozodiacal dust clouds
• The AU Mic Debris Disk: far-infrared and submillimeter resolved imaging
• A statistically significant lack of debris discs in medium separation binary systems
• Magnetic grain trapping and the hot excesses around early-type stars
• OIFITS 2: the 2nd version of the Data Exchange Standard for Optical (Visible/IR) Interferometry
• The Enhanced Resolution Imager and Spectrograph for the VLT
• Mass estimates for visual binaries with incomplete orbits
• Can eccentric debris disks be long-lived? A first numerical investigation and application to ${\zeta }^2$ Reticuli
• Improving Orbit Estimates for Incomplete Orbits with a New Approach to Priors -- with Applications from Black Holes to Planets
• NAOMI: the adaptive optics system of the Auxiliary Telescopes of the VLTI
• Constraints on the structure of hot exozodiacal dust belts
• Searching for faint companions with VLTI/PIONIER. II. 92 main sequence stars from the Exozodi survey
• Physical Orbit for Lambda Virginis and a Test of Stellar Evolution Models
• Fomalhaut b could be massive and sculpting the narrow, eccentric debris disc, if in mean-motion resonance with it
• Gas trapping of hot dust around main-sequence stars
• A near-infrared interferometric survey of debris-disk stars. VII. The hot/warm dust connection
• The Araucaria project: High-precision orbital parallaxes and masses of binary stars. I. VLTI/GRAVITY observations of ten double-lined spectroscopic binaries
• On the sensitivity of closure phases to faint companions in optical long baseline interferometry
• Hot exozodiacal dust: an exocometary origin?
• Towards reliable uncertainties in IR interferometry: The bootstrap for correlated statistical & systematic errors
• Extrasolar Kuiper Belts
• On the cavity of a debris disc carved by a giant planet
• Collisional modelling of the debris disc around HIP 17439
• Insights on the dynamical history of the Fomalhaut system - Investigating the Fom c hypothesis
• Hot Grain Dynamics by Electric Charging and Magnetic Trapping in Debris Disks
• Deep near-infrared interferometric search for low-mass companions around beta Pictoris
• GRAVITY: metrology
• Hot exozodis: cometary supply without trapping is unlikely to be the mechanism
• Bandwidth smearing in infrared long-baseline interferometry. Application to stellar companion search in fringe-scanning mode
• First L band detection of hot exozodiacal dust with VLTI/MATISSE
• GRAVITY for MATISSE -- Improving the MATISSE performance with the GRAVITY fringe tracker
• Twisted debris: how differential secular perturbations shape debris disks
• Nearby quintuple systems Kappa Tucanae and Xi Scorpii
• How much large dust could be present in hot exozodiacal dust systems?
• Review and prospects of hot exozodiacal dust research for future exo-Earth direct imaging missions
• High-contrast spectroscopy with the new VLT/ERIS instrument: Molecular maps and radial velocity of the gas giant AF Lep b
• Orbital Modeling of HII 1348B: An Eccentric Young Substellar Companion in the Pleiades
• Hot exozodiacal dust around Fomalhaut: The MATISSE perspective
• Bias-free model fitting of correlated data in interferometry
• Time-dependent Monte Carlo continuum radiative transfer
• Which is the most eccentric binary known? Insights from the 2023/4 pericenter passages of Zeta Boötis and Eta Ophiuchi