Toward Direct Detection of Hot Jupiters with Precision Closure Phase: Calibration Studies and First Results from the CHARA Array

Abstract

Direct detection of thermal emission from nearby hot Jupiters has greatly advanced our knowledge of extrasolar planets in recent years. Since hot Jupiter systems can be regarded as analogs of high contrast binaries, ground-based infrared long baseline interferometers have the potential to resolve them and detect their thermal emission with precision closure phase - a method that is immune to the systematic errors induced by the Earth's atmosphere. In this work, we present closure phase studies toward direct detection of nearby hot Jupiters using the CHARA interferometer array outfitted with the MIRC instrument. We carry out closure phase simulations and conduct a large number of observations for the best candidate υ And. Our experiments suggest the method is feasible with highly stable and precise closure phases. However, we also find much larger systematic errors than expected in the observations, most likely caused by dispersion across different wavelengths. We find that using higher spectral resolution modes (e.g., R=150) can significantly reduce the systematics. By combining all calibrators in an observing run together, we are able to roughly recalibrate the lower spectral resolution data, allowing us to obtain upper limits of the star-planet contrast ratios of υ And b across the H band. The data also allow us to get a refined stellar radius of 1.625\pm0.011 R\odot. Our best upper limit corresponds to a contrast ratio of 2.1\times10^3:1 with 90% confidence level at 1.52μm, suggesting that we are starting to have the capability of constraining atmospheric models of hot Jupiters with interferometry. With recent and upcoming improvements of CHARA/MIRC, the prospect of detecting emission from hot Jupiters with closure phases is promising.

30 pages, including 9 figures and 4 tables. Published in PASP in August 2011

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Cited by in corpus (16)

• PIONIER: a 4-telescope visitor instrument at VLTI
• Interferometric Observations of Rapidly Rotating Stars
• Resolving Vega and the inclination controversy with CHARA/MIRC
• Searching for faint companions with VLTI/PIONIER. I. Method and first results
• Three-dimensional interferometric, spectrometric, and planetary views of Procyon
• FIRST, a fibered aperture masking instrument. I. First on-sky test results
• CHARA/MIRC observations of two M supergiants in Perseus OB1: temperature, Bayesian modeling, and compressed sensing imaging
• On the sensitivity of closure phases to faint companions in optical long baseline interferometry
• Planet transit and stellar granulation detection with interferometry
• Dynamical Surface Imaging of lambda Andromedae
• Long Term Evolution of Surface Features on the Red Supergiant AZ Cyg
• Bandwidth smearing in infrared long-baseline interferometry. Application to stellar companion search in fringe-scanning mode
• Luminaries in the Sky: The TESS Legacy Sample of Bright Stars. I. Asteroseismic detections in naked-eye main-sequence and sub-giant solar-like oscillators
• Transiting exoplanets and magnetic spots characterized with optical interferometry
• Direct Imaging of Planet Transit Events
• Limb Darkening and Planetary Transits II: Intensity profile correction factors for a grid of model stellar atmospheres