A near-infrared interferometric survey of debris-disc stars

Absil, Olivier; Defrère, Denis; Foresto, V. Coudé du; Folco, E. Di; Mérand, A.; Augereau, J.-C.; Ertel, S.; Hanot, Charles; Kervella, P.; Mollier, B.; Scott, N.; Chen, Xiao; Monnier, John D.; Thureau, N.; Tuthill, P. G.; Brummelaar, Theo A. ten; McAlister, Harold A.; Sturmann, J.; Sturmann, L.; Turner, N.

doi:10.1051/0004-6361/201321673

Cited by 115 publications

(211 citation statements)

References 109 publications

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“…It could in particular first be applied to some systems where falling evaporating bodies (FEBs) are known, such as β Pictoris or HD 172555 (Beust et al 1998;Kiefer et al 2014). It could also be tried on systems where interferometric observations seem to show the presence of hot dust called exozodis (Absil et al 2013;Ertel et al 2015). The final aim would be to apply this astrometric method to randomly probe the inner parts of planetary systems and discover hidden components, such as FEBs, asymmetric exozodis, or even trailing clumps behind planets, such as the Earth's resonant ring that corotates with Earth (Wyatt et al 1999).…”

Section: Discussionmentioning

confidence: 99%

Effects of disc asymmetries on astrometric measurements

Kral

Kennedy

Souami

2016

A&A

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Astrometry covers a parameter space that cannot be reached by RV or transit methods to detect terrestrial planets on wide orbits. In addition, high accuracy astrometric measurements are necessary to measure the inclination of the planet's orbits. Here we investigate the principles of an artefact of the astrometric approach, namely the displacement of the photo-centre owing to inhomogeneities in a dust disc around the parent star. Indeed, theory and observations show that circumstellar discs can present strong asymmetries. We model the pseudo-astrometric signal caused by these inhomogeneities, asking whether a dust clump in a disc can mimic the astrometric signal of an Earth-like planet. We show that these inhomogeneities cannot be neglected when using astrometry to find terrestrial planets. We provide the parameter space for which these inhomogeneities can affect the astrometric signals but still not be detected by mid-IR observations. We find that a small cross section of dust corresponding to a cometary mass object is enough to mimic the astrometric signal of an Earth-like planet. Astrometric observations of protoplanetary discs to search for planets can also be affected by the presence of inhomogeneities. Some further tests are given to confirm whether an observation is a real astrometric signal from a planet or an impostor. Eventually, we also study the case where the cross-section of dust is high enough to provide a detectable IR-excess and to have a measurable photometric displacement by actual instruments such as Gaia, IRAC, or GRAVITY. We suggest a new method, which consists of using astrometry to quantify asymmetries (clumpiness) in inner debris discs that cannot be otherwise resolved.

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Section: Discussionmentioning

confidence: 99%

Effects of disc asymmetries on astrometric measurements

Kral

Kennedy

Souami

2016

A&A

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“…As we will describe later, both of these possibilities predict that the locations of warm components will be set by the snow line (i.e., where water ice condensation/ sublimation occurs). However, these hypotheses differ as to whether it is the primordial snow line or the current snow line 1 identified five dust components that a debris disk can possess, which in addition to the warm and cold components described here, also include a blowout halo of small grains outside of the cold belt (Augereau et al 2001;Su et al 2005); exozodiacal dust that is hotter and nearer to the star than the warm dust and emits at ∼10 μm (Kennedy & Wyatt 2013;Ballering et al 2014); and very hot dust emitting in the near-IR (Absil et al 2013;Ertel et al 2014), likely composed of nanograins trapped in the stellar magnetic field .…”

Section: Introductionmentioning

confidence: 86%

What Sets the Radial Locations of Warm Debris Disks?

Ballering

Rieke

et al. 2017

ApJ

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The architectures of debris disks encode the history of planet formation in these systems. Studies of debris disks via their spectral energy distributions (SEDs) have found infrared excesses arising from cold dust, warm dust, or a combination of the two. The cold outer belts of many systems have been imaged, facilitating their study in great detail. Far less is known about the warm components, including the origin of the dust. The regularity of the disk temperatures indicates an underlying structure that may be linked to the water snow line. If the dust is generated from collisions in an exo-asteroid belt, the dust will likely trace the location of the water snow line in the primordial protoplanetary disk where planetesimal growth was enhanced. If instead the warm dust arises from the inward transport from a reservoir of icy material farther out in the system, the dust location is expected to be set by the current snow line. We analyze the SEDs of a large sample of debris disks with warm components. We find that warm components in single-component systems (those without detectable cold components) follow the primordial snow line rather than the current snow line, so they likely arise from exo-asteroid belts. While the locations of many warm components in two-component systems are also consistent with the primordial snow line, there is more diversity among these systems, suggesting additional effects play a role.

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“…Dust is usually distributed as a belt within the periphery of the system in a way analogous to the Kuiper belt in our Solar System. While most of the known debris disks present cold dust in narrow belts at tens of au, a small fraction host a hot dust component within a few au, analogous to the Asteroid belt or Zodiacal dust (e.g., Absil et al 2013;Marino et al 2017).…”

Section: Introductionmentioning

confidence: 99%

ALMA Discovery of Dust Belts around Proxima Centauri

Anglada

Amado

Ortiz

et al. 2017

ApJL

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Proxima Centauri, the star closest to our Sun, is known to host at least one terrestrial planet candidate in a temperate orbit. Here we report the ALMA detection of the star at 1.3 mm wavelength and the discovery of a belt of dust orbiting around it at distances ranging between 1 and 4 au, approximately. Given the low luminosity of the Proxima Centauri star, we estimate a characteristic temperature of about 40 K for this dust, which might constitute the dust component of a small-scale analog to our solar system Kuiper belt. The estimated total mass, including dust and bodies up to 50 km in size, is of the order of 0.01 Earth masses, which is similar to that of the solar Kuiper belt. Our data also show a hint of warmer dust closer to the star. We also find signs of two additional features that might be associated with the Proxima Centauri system, which, however, still require further observations to be confirmed: an outer extremely cold (about 10 K) belt around the star at about 30 au, whose orbital plane is tilted about 45 degrees with respect to the plane of the sky; and additionally, we marginally detect a compact 1.3 mm emission source at a projected distance of about 1.2 arcsec from the star, whose nature is still unknown.

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A near-infrared interferometric survey of debris-disc stars

Cited by 115 publications

References 109 publications

Effects of disc asymmetries on astrometric measurements

Effects of disc asymmetries on astrometric measurements

What Sets the Radial Locations of Warm Debris Disks?

ALMA Discovery of Dust Belts around Proxima Centauri

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