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See detailPlanet Formation Imager (PFI): Introduction and technical considerations
Monnier, J. D.; Kraus, S.; Buscher, D. et al

in Proceedings of SPIE - The International Society for Optical Engineering (2014), 9146

Complex non-linear and dynamic processes lie at the heart of the planet formation process. Through numerical simulation and basic observational constraints, the basics of planet formation are now coming ... [more ▼]

Complex non-linear and dynamic processes lie at the heart of the planet formation process. Through numerical simulation and basic observational constraints, the basics of planet formation are now coming into focus. High resolution imaging at a range of wavelengths will give us a glimpse into the past of our own solar system and enable a robust theoretical framework for predicting planetary system architectures around a range of stars surrounded by disks with a diversity of initial conditions. Only long-baseline interferometry can provide the needed angular resolution and wavelength coverage to reach these goals and from here we launch our planning efforts. The aim of the "Planet Formation Imager" (PFI) project is to develop the roadmap for the construction of a new near-/mid-infrared interferometric facility that will be optimized to unmask all the major stages of planet formation, from initial dust coagulation, gap formation, evolution of transition disks, mass accretion onto planetary embryos, and eventual disk dispersal. PFI will be able to detect the emission of the cooling, newlyformed planets themselves over the first 100 Myrs, opening up both spectral investigations and also providing a vibrant look into the early dynamical histories of planetary architectures. Here we introduce the Planet Formation Imager (PFI) Project (www.planetformationimager.org) and give initial thoughts on possible facility architectures and technical advances that will be needed to meet the challenging top-level science requirements. © 2014 SPIE. [less ▲]

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See detailThe science case for the Planet Formation Imager (PFI)
Kraus, S.; Monnier, J.; Harries, T. et al

in Proceedings of SPIE - The International Society for Optical Engineering (2014), 9146

Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar ... [more ▼]

Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar birth. Although important work has already been, and is still being done both in theory and observation, a full understanding of the physics of planet formation can only be achieved by opening observational windows able to directly witness the process in action. The key requirement is then to probe planet-forming systems at the natural spatial scales over which material is being assembled. By definition, this is the so-called Hill Sphere which delineates the region of influence of a gravitating body within its surrounding environment. The Planet Formation Imager project (PFI; http://www.planetformationimager.org) has crystallized around this challenging goal: to deliver resolved images of Hill-Sphere-sized structures within candidate planethosting disks in the nearest star-forming regions. In this contribution we outline the primary science case of PFI. For this purpose, we briefly review our knowledge about the planet-formation process and discuss recent observational results that have been obtained on the class of transition disks. Spectro-photometric and multi-wavelength interferometric studies of these systems revealed the presence of extended gaps and complex density inhomogeneities that might be triggered by orbiting planets. We present detailed 3-D radiation-hydrodynamic simulations of disks with single and multiple embedded planets, from which we compute synthetic images at near-infrared, mid-infrared, far-infrared, and sub-millimeter wavelengths, enabling a direct comparison of the signatures that are detectable with PFI and complementary facilities such as ALMA. From these simulations, we derive some preliminary specifications that will guide the array design and technology roadmap of the facility. © 2014 SPIE. [less ▲]

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See detailExpanding the CHARA/FLUOR hot disk survey
Mennesson, B.; Scott, N.; Ten Brummelaar, T. et al

in Journal of Astronomical Instrumentation (2013), 2(2), 1340010

Little is presently known about the hot (>300 K) dust component of debris disks surrounding main sequence stars, similar to the zodiacal dust cloud found in the inner solar system.While extensive surveys ... [more ▼]

Little is presently known about the hot (>300 K) dust component of debris disks surrounding main sequence stars, similar to the zodiacal dust cloud found in the inner solar system.While extensive surveys have been carried out from space, the majority of detections have surprisingly come from the ground, where near infrared interferometric observations have recently revealed small (∼1%) resolved excesses around a dozen nearby main sequence stars. Most of these results have come from the CHARA array “FLUOR” instrument (Mt. Wilson, CA), which has demonstrated the best sensitivity worldwide so far for this type of studies, and has carried out an initial survey of ∼40 stars. In order to further understand the origin of this “hot dust phenomenon”, we will extend this initial survey to a larger number of stars and lower excess detection limits, i.e. higher visibility accuracy providing higher contrast measurements. To this end, two major instrumental developments are underway at CHARA. The first one aims at improving FLUOR’s sensitivity to a median K-band magnitude limit of 5 (making 200 targets available). The second development is based on a method that we recently developed for accurate (better than 0.1%) null depth measurements of stars, and that can be extended to regular interferometric visibility measurements. [less ▲]

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See detailRound table discussion
Coude Du Foresto, V.; Hummel, C. A.; Perrin, G. et al

in Proceedings of the JENAM 2010 Symposium (2010, September 01)

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See detailExoplanet Characterization and the Search for Life
Kasting, James; Traub, W.; Roberge, A. et al

E-print/Working paper (2009)

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces ... [more ▼]

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces with spectroscopy. Rocky planets within their star's habitable zones have the highest priority, as these have the potential to harbor life. Our science goal is to find and characterize all nearby exoplanets; this requires that we measure the mass, orbit, and spectroscopic signature of each one at visible and infrared wavelengths. The techniques for doing this are at hand today. Within the decade we could answer long-standing questions about the evolution and nature of other planetary systems, and we could search for clues as to whether life exists elsewhere in our galactic neighborhood. [less ▲]

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See detailDust in the inner regions of debris disks around A stars
Akeson, R. L.; Ciardi, D. R.; Millan-Gabet, R. et al

in Astrophysical Journal (2009), 691

We present infrared interferometric observations of the inner regions of two A-star debris disks, beta Leo and zeta Lep, using the FLUOR instrument at the CHARA interferometer on both short (30 m) and ... [more ▼]

We present infrared interferometric observations of the inner regions of two A-star debris disks, beta Leo and zeta Lep, using the FLUOR instrument at the CHARA interferometer on both short (30 m) and long (> 200 m) baselines. For the target stars, the short-baseline visibilities are lower than expected for the stellar photosphere alone, while those of a check star, delta Leo, are not. We interpret this visibility offset of a few percent as a near-infrared (NIR) excess arising from dust grains which, due to the instrumental field of view, must be located within several AU of the central star. For beta Leo, the NIR excess-producing grains are spatially distinct from the dust which produces the previously known mid-infrared (MIR) excess. For zeta Lep, the NIR excess may be spatially associated with the MIR excess-producing material. We present simple geometric models which are consistent with the NIR and MIR excesses and show that for both objects, the NIR-producing material is most consistent with a thin ring of dust near the sublimation radius, with typical grain sizes smaller than the nominal radiation pressure blowout radius. Finally, we discuss possible origins of the NIR-emitting dust in the context of debris disk evolution models. [less ▲]

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See detailInfrared Interferometric Gravity Darkening Observations of Vega with CHARA/FLUOR
Aufdenberg, J.; Mérand, A.; Coudé Du Foresto, V. et al

in Coudé du Foresto, Vincent; Rouan, Daniel; Rousset, Gérard (Eds.) Visions for Infrared Astronomy (2006, March)

We have obtained high-precision measurements of Vega at projected baselines between 103 m and 273 m with the CHARA Array using the (FLUOR) beam combiner in the K' band. A strongly gravity-darkened model ... [more ▼]

We have obtained high-precision measurements of Vega at projected baselines between 103 m and 273 m with the CHARA Array using the (FLUOR) beam combiner in the K' band. A strongly gravity-darkened model atmosphere is in general agreement with both our interferometric data and archival spectrophotometry. This model indicates that Vega is rotating at 91%ofitsangular break-uprateandthatthepole-to-equator effectivetemperaturedifference is 2250 K. [less ▲]

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See detailCurrent generation arrays: current status, getting the most out of them and future development
Akeson, R.; ten Brummelaar, T.; Eisner, J. et al

in “Future Directions for Interferometry” (2006)

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