The HOSTS Survey: Suspected variable dust emission and constraints on companions around θ Boo

Abstract

During the HOSTS survey by the LBTI, an excess emission from the main sequence star θ Boo (F7V spectral type, 14.5pc distance) was observed. This excess indicates the presence of exozodiacal dust near the habitable zone (HZ) of the star. Previous observations from Spitzer and Herschel showed no sign of outer cold dust within their respective detection limits. Additional nulling and high-contrast AO observations were taken to spatially constrain the dust distribution, search for variability, and directly image potential companions in the system. This study presents the results of these observations and provides an interpretation of the inner system's architecture. The star was observed using the LBTI's N'-band nulling mode during three epochs in 2017, 2018, and 2023. The dust distribution is modeled and constrained for each epoch using the standard LBTI nulling pipeline, assuming a vertically thin disk with a face-on inclination. In addition, high-contrast AO observations are performed in the L'-band and H-band to constrain the presence of substellar companions around the star. Several solutions are found for the dust distribution, and for each epoch. However, the LBTI nulling observations are not able to discriminate between them. Using the upper limits from previous observations, we constrain the representative size of the dust grains around 3-5$\mu$m. A tentative increase in dust brightness is also measured at the Earth-equivalent insolation distance between 2017 and 2023. Several options are considered to explain the origin of the observed dust and its variability, but no clear sources could be identified from the current observations. Partly because our high-contrast AO observations could only constrain the presence of companions down to $11M_{\text{Jup}}$ at 1.3" separation.

arXiv commentPublished in A&A. 22 pages, 14 figures, 7 tables

References in corpus (78)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• Habitable Zones Around Main-Sequence Stars: New Estimates
• Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945
• Angular Differential Imaging: a Powerful High-Contrast Imaging Technique
• Detection and Characterization of Exoplanets and Disks using Projections on Karhunen-Loeve Eigenimages
• The Geneva-Copenhagen Survey of the Solar neighbourhood III. Improved distances, ages, and kinematics
• The James Webb Space Telescope Mission
• The Science Performance of JWST as Characterized in Commissioning
• Fundamental limitations of high contrast imaging set by small sample statistics
• Spectral and Photometric Diagnostics of Giant Planet Formation Scenarios
• PynPoint: An Image Processing Package for Finding Exoplanets
• A dual-frequency sub-arcsecond study of proto-planetary disks at mm wavelengths: First evidence for radial variations of the dust properties
• Debris Disks: Structure, Composition, and Variability
• Debris disks around Sun-like stars
• Water Delivery and Giant Impacts in the 'Grand Tack' Scenario
• The Mid-Infrared Instrument for the James Webb Space Telescope, VI: The Medium Resolution Spectrometer
• Frequency of Debris Disks around Solar-Type Stars: First Results from a Spitzer/MIPS Survey
• Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs
• Stellar Diameters and Temperatures III. Main Sequence A, F, G, & K Stars: Additional high-precision measurements and empirical relations
• JWST MIRI flight performance: The Medium-Resolution Spectrometer
• VIP: Vortex Image Processing package for high-contrast direct imaging
• The Insignificance of P-R Drag in Detectable Extrasolar Planetesimal Belts
• New Debris Disks Around Nearby Main Sequence Stars: Impact on The Direct Detection of Planets
• Maximizing the ExoEarth Candidate Yield from a Future Direct Imaging Mission
• Chromospheric activity as age indicator
• The Collisional Evolution of Debris Disks
• Debris disk size distributions: steady state collisional evolution with P-R drag and other loss processes
• Abundances in the Local Region II: F, G and K Dwarfs and Subgiants
• Atmospheres from very low-mass stars to extrasolar planets
• A catalog of bright calibrator stars for 200-meter baseline near-infrared stellar interferometry
• 99 Herculis: Host to a Circumbinary Polar-ring Debris Disk
• The HOSTS survey for exozodiacal dust: Observational results from the complete survey
• Pseudomagnitudes and Differential Surface Brightness: Application to the apparent diameter of stars
• Rapid disappearance of a warm, dusty circumstellar disk
• Direct detection of exoplanets in the 3 -- 10 micron range with E-ELT/METIS
• Dynamical evolution of an eccentric planet and a less massive debris disc
• Magellan Adaptive Optics first-light observations of the exoplanet beta Pic b. II. 3-5 micron direct imaging with MagAO+Clio, and the empirical bolometric luminosity of a self-luminous giant planet
• Incidence of debris discs around FGK stars in the solar neighbourhood
• Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey
• The Exozodiacal Dust Problem for Direct Observations of ExoEarths
• On the alignment of debris disks and their host stars' rotation axis -implications for spin-orbit misalignment in exoplanetary systems
• The LEECH Exoplanet Imaging Survey: Limits on Planet Occurrence Rates Under Conservative Assumptions
• Variability of the Infrared Excess of Extreme Debris Disks
• Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks
• Nulling interferometry: impact of exozodiacal clouds on the performance of future life-finding space missions
• The Detectability of Exo-Earths and Super-Earths Via Resonant Signatures in Exozodiacal Clouds
• Nulling Data Reduction and On-Sky Performance of the Large Binocular Telescope Interferometer
• The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system
• Improving Interferometric Null Depth Measurements using Statistical Distributions: Theory and First Results with the Palomar Fiber Nuller
• First-light LBT nulling interferometric observations: warm exozodiacal dust resolved within a few AU of eta Corvi
• Cometary impactors on the TRAPPIST-1 planets can destroy all planetary atmospheres and rebuild secondary atmospheres on planets f, g, h
• SPITZER/IRAC-MIPS Survey of NGC2451A and B: Debris Disks at 50-80 million years
• Imaging low-mass planets within the habitable zone of α Centauri
• Inner mean-motion resonances with eccentric planets: A possible origin for exozodiacal dust clouds
• BAFFLES: Bayesian Ages for Field Lower-Mass Stars
• A statistically significant lack of debris discs in medium separation binary systems
• Thermal Infrared Imaging of MWC 758 with the Large Binocular Telescope: Planetary Driven Spiral Arms?
• Extreme Debris Disk Variability -- Exploring the Diverse Outcomes of Large Asteroid Impacts During the Era of Terrestrial Planet Formation
• Warm exo-Zodi from cool exo-Kuiper belts: the significance of P-R drag and the inference of intervening planets
• Exo-zodi modelling for the Large Binocular Telescope Interferometer
• Can eccentric debris disks be long-lived? A first numerical investigation and application to ${\zeta }^2$ Reticuli
• Exoplanets with ELT-METIS I: Estimating the direct imaging exoplanet yield around stars within 6.5 parsecs
• Large Interferometer For Exoplanets (LIFE): VI. Detecting rocky exoplanets in the habitable zones of Sun-like stars
• Dust size and spatial distributions in debris discs: predictions for exozodiacal dust dragged in from an exo-Kuiper belt
• Extrasolar comets : the origin of dust in exozodiacal disks?
• Target Selection for the LBTI Exozodi Key Science Program
• Large Binocular Telescope Interferometer Adaptive Optics: On-sky performance and lessons learned
• Models of the Eta Corvi debris disk from the Keck Interferometer, Spitzer and Herschel
• Extreme Variability of the V488 Persei Debris Disk
• Using warm dust to constrain unseen planets
• The HOSTS survey: evidence for an extended dust disk and constraints on the presence of giant planets in the Habitable Zone of $\beta$ Leo
• Studying the Evolution of Warm Dust Encircling BD +20 307 Using SOFIA
• A PR drag origin for the Fomalhaut disk's pervasive inner dust: constraints on collisional strengths, icy composition, and embedded planets
• Chromospheric Variability in Early F-type Stars
• Mid-infrared time-domain study of recent dust production events in the extreme debris disc of TYC 4209-1322-1
• A recent history of science cases for interferometry