A near-infrared interferometric survey of debris disc stars. II. CHARA/FLUOR observations of six early-type dwarfs
arXiv:0806.4936 · doi:10.1051/0004-6361:200810008
Abstract
High-precision interferometric observations of six early-type main sequence stars known to harbour cold debris discs have been obtained in the near-infrared K band with the FLUOR instrument at the CHARA Array. The measured squared visibilities are compared to the expected visibility of the stellar photospheres based on theoretical photospheric models taking into account rotational distortion, searching for potential visibility reduction at short baselines due to circumstellar emission. Our observations bring to light the presence of resolved circumstellar emission around one of the six target stars (zeta Aql) at the 5 sigma level. The morphology of the emission source cannot be directly constrained because of the sparse spatial frequency sampling of our interferometric data. Using complementary adaptive optics observations and radial velocity measurements, we find that the presence of a low-mass companion is a likely origin for the excess emission. The potential companion has a K-band contrast of four magnitudes, a most probable mass of about 0.6 Msun, and is expected to orbit between about 5.5 AU and 8 AU from its host star assuming a purely circular orbit. Nevertheless, by adjusting a physical debris disc model to the observed Spectral Energy Distribution of the zeta Aql system, we also show that the presence of hot dust within 10 AU from zeta Aql, producing a total thermal emission equal to 1.69 +- 0.31% of the photospheric flux in the K band, is another viable explanation for the observed near-infrared excess. Our re-interpretation of archival near- to far-infrared photometric measurements shows however that cold dust is not present around zeta Aql at the sensitivity limit of the IRS and MIPS instruments onboard Spitzer, and urges us to remove zeta Aql from the category of bona fide debris disc stars.
arXiv comment14 pages, accepted for publication in A&A
References in corpus (30)
- The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
- First Results from the CHARA Array. II. A Description of the Instrument
- Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I
- A planetary system as the origin of structure in Fomalhaut's dust belt
- Debris Disk Evolution Around A Stars
- Transience of hot dust around sun-like stars
- Imaging the Surface of Altair
- Spitzer IRS Spectroscopy of IRAS-Discovered Debris Disks
- Frequency of Debris Disks around Solar-Type Stars: First Results from a Spitzer/MIPS Survey
- The Vega Debris Disk -- A Surprise from Spitzer
- First Results from the CHARA Array. I. An Interferometric and Spectroscopic Study of the Fast Rotator alpha Leonis (Regulus)
- Vega is a rapidly rotating star
- Terrestrial Planet Formation I. The Transition from Oligarchic Growth to Chaotic Growth
- First Results from the CHARA Array VII: Long-Baseline Interferometric Measurements of Vega Consistent with a Pole-On, Rapidly Rotating Star
- The diameters of Alpha Centauri A and B - A comparison of the asteroseismic and VINCI/VLTI views
- Prospects for Detection of Catastrophic Collisions in Debris Disks
- Circumstellar material in the Vega inner system revealed by CHARA/FLUOR
- Detecting the Dusty Debris of Terrestrial Planet Formation
- A catalog of bright calibrator stars for 200-meter baseline near-infrared stellar interferometry
- Rotational velocities of A-type stars I. Measurement of vsini in the southern hemisphere
- Data reduction methods for single-mode optical interferometry - Application to the VLTI two-telescopes beam combiner VINCI
- Sub-millimeter images of a dusty Kuiper belt around eta Corvi
- A near-infrared interferometric survey of debris disk stars. I. Probing the hot dust content around epsilon Eridani and tau Ceti with CHARA/FLUOR
- On the Near-Infrared Size of Vega
- Resolving the Effects of Rotation in Altair with Long-Baseline Interferometry
- First Results from the CHARA Array. III. Oblateness, Rotational Velocity and Gravity Darkening of Alderamin
- On the observability of resonant structures in planetesimal disks due to planetary migration
- Crystalline Silicate Feature of the Vega-like star HD145263
- Wide field interferometric imaging with single-mode fibers
- Testing Stellar Models With An Improved Physical Orbit for 12 Bootis
Cited by in corpus (39)
- PIONIER: a 4-telescope visitor instrument at VLTI
- Stellar Diameters and Temperatures I. Main Sequence A, F, & G Stars
- Debris Disks: Seeing Dust, Thinking of Planetesimals and Planets
- Asteroid Belts in Debris Disk Twins: VEGA and FOMALHAUT
- A near-infrared interferometric survey of debris disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR
- Stellar Diameters and Temperatures VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs
- Exo--Zodiacal Dust Levels for Nearby Main Sequence Stars
- Scattering of small bodies by planets: a potential origin for exozodiacal dust ?
- A near-infrared interferometric survey of debris-disc stars. IV. An unbiased sample of 92 southern stars observed in H-band with VLTI/PIONIER
- Sublimation Temperature of Circumstellar Dust Particles and Its Importance for Dust Ring Formation
- Hot exozodiacal dust resolved around Vega with IOTA/IONIC
- A Comprehensive Census of Nearby Infrared Excess Stars
- An interferometric study of the Fomalhaut inner debris disk. III. Detailed models of the exozodiacal disk and its origin
- A possible architecture of the planetary system HR 8799
- Searching for faint companions with VLTI/PIONIER. I. Method and first results
- The short-lived production of exozodiacal dust in the aftermath of a dynamical instability in planetary systems
- Resolving the hot dust around HD69830 and eta Corvi with MIDI and VISIR
- Dust in the inner regions of debris disks around A stars
- An interferometric study of the Fomalhaut inner debris disk. I. Near-infrared detection of hot dust with VLTI/VINCI
- Polarization measurements of hot dust stars and the local interstellar medium
- Near-infrared emission from sublimating dust in collisionally active debris disks
- Magnetic grain trapping and the hot excesses around early-type stars
- Hot circumstellar material resolved around beta Pic with VLTI/PIONIER
- The Solar Neighborhood XXIX: The Habitable Real Estate of our Nearest Stellar Neighbors
- The Pseudo-zodi Problem for Edge-on Planetary Systems
- Formation and evolution of planetary systems: the impact of high angular resolution optical techniques
- A dim candidate companion to εCephei
- Multi-Epoch Observations of HD69830: High Resolution Spectroscopy and Limits to Variability
- A near-infrared interferometric survey of debris-disk stars. VII. The hot/warm dust connection
- Hot exozodiacal dust: an exocometary origin?
- Models of the Eta Corvi debris disk from the Keck Interferometer, Spitzer and Herschel
- Infrared Absolute Calibration I: Comparison of Sirius with Fainter Calibration Stars
- 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
- Polarization of stars with debris disks: comparing observations with models
- A catalog of collected debris disks: properties, classifications and correlations between disks and stars/planets
- A study of the rapid rotator Aql: differential surface rotation?
- How much large dust could be present in hot exozodiacal dust systems?
- VLTI/MATISSE observations of the hot dust around Pictoris: Observing faint objects with MATISSE