References of "Beichman, C. A"
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See detailVizieR Online Data Catalog: Planet candidates discovered using K2's 1st yr (Crossfield+, 2016)
Crossfield, I. J. M.; Ciardi, D. R.; Petigura, E. A. et al

in Planet candidates discovered using K2's 1st yr (Crossfield+, 2016) (2016)

We select our FGK stellar sample from the all-sky Transiting Exoplanet Survey Satellite (TESS) Dwarf Catalog (TDC; Stassun et al. 2014, arXiv:1410.6379). We extract time-series photometry from the target ... [more ▼]

We select our FGK stellar sample from the all-sky Transiting Exoplanet Survey Satellite (TESS) Dwarf Catalog (TDC; Stassun et al. 2014, arXiv:1410.6379). We extract time-series photometry from the target pixel files provided by the K2 project using circular, stationary, soft-edged apertures. See section 2 for further explanations. We obtained high-resolution optical spectra of 83 planet candidate hosts using the HIRES echelle spectrometer on the 10m Keck I telescope (R=55000). We obtained spectra of 27 candidate host stars using the Levy high-resolution optical spectrograph mounted at the Automated Planet Finder (APF; R~80000 or 100000). We obtained spectra of a small number of candidate stellar hosts using the FEROS fiber-fed echelle spectrograph at the 2.2m MPG telescope (R~48000). See section 3.1 for further details. We obtained high-resolution imaging (HRI) for 164 of our candidate systems. Our primary instrument for this work was NIRC2 at the 10m Keck II telescope, with which we observed 110 systems. As part of multi-semester program GN-2015B-LP-5 (PI Crossfield) at Gemini Observatory, we observed 40 systems with the NIRI camera in the K-band. We also observed 33 stars with PHARO/PALM-3000 at the 5m Hale Telescope and 14 systems with LMIRCam at LBT, all at the K-band. We observed 39 stars at visible wavelengths using the automated Robo-AO laser adaptive optics system at the Palomar 1.5m telescope. Through our Long-Term Gemini program we also acquired high-resolution speckle imaging of 32 systems in narrowband filters centered at 692 and 880nm using the DSSI camera at the Gemini North telescope. See section 3.3 for further explanations. (7 data files). [less ▲]

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See detail197 Candidates and 104 Validated Planets in K2' First Five Fields
Crossfield, I. J. M.; Ciardi, D. R.; Petigura, E. A. et al

in Astrophysical Journal Supplement Series (2016), 226

We present 197 planet candidates discovered using data from the first year of the NASA K2 mission (Campaigns 0-4), along with the results of an intensive program of photometric analyses, stellar ... [more ▼]

We present 197 planet candidates discovered using data from the first year of the NASA K2 mission (Campaigns 0-4), along with the results of an intensive program of photometric analyses, stellar spectroscopy, high-resolution imaging, and statistical validation. We distill these candidates into sets of 104 validated planets (57 in multi-planet systems), 30 false positives, and 63 remaining candidates. Our validated systems span a range of properties, with median values of R P = 2.3 {R}\oplus , P = 8.6 days, {T}{eff} = 5300 K, and Kp = 12.7 mag. Stellar spectroscopy provides precise stellar and planetary parameters for most of these systems. We show that K2 has increased by 30% the number of small planets known to orbit moderately bright stars (1-4 R ⊕, Kp = 9-13 mag). Of particular interest are 76 planets smaller than 2 R ⊕, 15 orbiting stars brighter than Kp = 11.5 mag, 5 receiving Earth-like irradiation levels, and several multi-planet systems—including 4 planets orbiting the M dwarf K2-72 near mean-motion resonances. By quantifying the likelihood that each candidate is a planet we demonstrate that our candidate sample has an overall false positive rate of 15%-30%, with rates substantially lower for small candidates (\lt 2{R}\oplus ) and larger for candidates with radii \gt 8{R}\oplus and/or with P\lt 3 {{days}}. Extrapolation of the current planetary yield suggests that K2 will discover between 500 and 1000 planets in its planned four-year mission, assuming sufficient follow-up resources are available. Efficient observing and analysis, together with an organized and coherent follow-up strategy, are essential for maximizing the efficacy of planet-validation efforts for K2, TESS, and future large-scale surveys. [less ▲]

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See detailModeling the η Corvi debris disk from the sub-AU scale to its outermost regions
Lebreton, J.; Beichman, C. A.; Bryden, G. et al

Poster (2014, March 01)

Dusty debris disks surrounding main sequence stars are thought to be analogues to thepopulations of small bodies of the Solar System (asteroids, comets/icy bodies and dust grains), however with often much ... [more ▼]

Dusty debris disks surrounding main sequence stars are thought to be analogues to thepopulations of small bodies of the Solar System (asteroids, comets/icy bodies and dust grains), however with often much higher masses and associated dust production rates. Mecanisms such as massive collisions or LHB-like events must therefore be invoked to justify their existence. This is especially striking for the nearby F2V star η Corvi that shows a very strong mid- and far-infrared excess despite an estimated age of ~1.4 Gyr (Lisse et al. 2012, Wyatt et al. 2005). We present new observations of the η Crv debris disk obtained in the far-infrared with Herschel/PACS and SPIRE and in the mid-infrared with the Keck Interferometer Nuller (Millan-Gabet et al. 2011). The Herschel/PACS images at 70, 100 and 160 μm reveal a well resolved belt of cold material at ~130 AU, as well as an unresolved component in the innermost parts of the system. This warmer counterpart is resolved in the mid-infrared as a strong null excess originating from within the ~2x4 AU field-of-view of the interferometer, which is reminiscent of the architecture of the Fomalhaut debris disk (Mennesson et al. 2012, Lebreton et al. 2013). The signature of warm silicate dust is also very clear in Spitzer/IRS high-resolution spectra (Chen et al. 2006) at intermediate wavelengths (10-35 μm). We undertake to establish a consistent model of the debris disk from the sub-AU scale to its outermost regions using the GRaTer radiative transfer code (Augereau et al. 1999a, Lebreton et al. 2013) by adjusting simultaneously the interferometric nulls, the resolved Herschel images and the spectro-photometric data against a large parameter space. Our analysis providesaccurate estimates of the fundamental parameters of the disk: its surface density profile, grain size distribution and mass, making it possible to unveil the origin of the dust and the relation between the cold (~50 K) Kuiper-like belt and the warm (~500 K) exo-zodiacal disk. We further discuss the possible existence of an additional dust population at intermediate temperatures and its nature. η Corvi will be of prime interest for future observations with the JWST. We finally make predictions of the ability of NIRCam and MIRI to image details in the disk at high contrast with both spatial and spectral resolution in order to obtain a better view of this complex planetary system. [less ▲]

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See detailDo we Need to Solve the Exozodi Question? If Yes, How to Best Solve It?
Absil, Olivier ULiege; Eiroa, C.; Augereau, J. et al

in Coudé du Foresto, Vincent; Gelino, Dawn; Ribas, Ignasi (Eds.) Pathways Towards Habitable Planets (2010, October 01)

When observing an extrasolar planetary system, the most luminous component after the star itself is generally the light scattered and/or thermally emitted by a population of micron-sized dust grains ... [more ▼]

When observing an extrasolar planetary system, the most luminous component after the star itself is generally the light scattered and/or thermally emitted by a population of micron-sized dust grains. These grains are expected to be continuously replenished by the collisions and evaporation of larger bodies just as in our solar zodiacal cloud. Exozodiacal clouds (“exozodis”) must therefore be seriously taken into account when attempting to directly image faint Earth-like planets (exoEarths, for short). This paper summarizes the oral contributions and discussions that took place during the Satellite Meeting on exozodiacal dust disks, in an attempt to address the following two questions: Do we need to solve the exozodi question? If yes, how to best solve it? [less ▲]

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See detailResolving the cold debris disc around a planet-hosting star. PACS photometric imaging observations of q1 Eridani (HD 10647, HR 506)
Liseau, R.; Eiroa, C.; Fedele, D. et al

in Astronomy and Astrophysics (2010), 518

Context. About two dozen exo-solar debris systems have been spatially resolved. These debris discs commonly display a variety of structural features such as clumps, rings, belts, excentric distributions ... [more ▼]

Context. About two dozen exo-solar debris systems have been spatially resolved. These debris discs commonly display a variety of structural features such as clumps, rings, belts, excentric distributions and spiral patterns. In most cases, these features are believed to be formed, shaped and maintained by the dynamical influence of planets orbiting the host stars. In very few cases has the presence of the dynamically important planet(s) been inferred from direct observation. Aims. The solar-type star q1 Eri is known to be surrounded by debris, extended on scales of 30”. The star is also known to host at least one planet, albeit on an orbit far too small to make it responsible for structures at distances of tens to hundreds of AU. The aim of the present investigation is twofold: to determine the optical and material properties of the debris and to infer the spatial distribution of the dust, which may hint at the presence of additional planets. Methods. The Photodetector Array Camera and Spectrometer (PACS) aboard the Herschel Space Observatory allows imaging observations in the far infrared at unprecedented resolution, i.e. at better than 6” to 12” over the wavelength range of 60 μm to 210 μm. Together with the results from ground-based observations, these spatially resolved data can be modelled to determine the nature of the debris and its evolution more reliably than what would be possible from unresolved data alone. Results. For the first time has the q1 Eri disc been resolved at far infrared wavelengths. The PACS observations at 70 μm, 100 μm and 160 μm reveal an oval image showing a disc-like structure in all bands, the size of which increases with wavelength. Assuming a circular shape yields the inclination of its equatorial plane with respect to that of the sky, i > 53°. The results of image de-convolution indicate that i likely is larger than 63°, where 90° corresponds to an edge-on disc. Conclusions. The observed emission is thermal and optically thin. The resolved data are consistent with debris at temperatures below 30 K at radii larger than 120 AU. From image de-convolution, we find that q1 Eri is surrounded by an about 40 AU wide ring at the radial distance of ~85 AU. This is the first real Edgeworth-Kuiper Belt analogue ever observed. [less ▲]

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See detailTechnology for a Mid-IR Flagship Mission to Characterize Earth-like Exoplanets
Lawson, P. R.; Absil, Olivier ULiege; Akeson, R. L. et al

E-print/Working paper (2009)

The exploration of Earth-like exoplanets will be enabled at mid-infrared wavelengths through technology and engineering advances in nulling interferometry and precision formation flying. Nulling ... [more ▼]

The exploration of Earth-like exoplanets will be enabled at mid-infrared wavelengths through technology and engineering advances in nulling interferometry and precision formation flying. Nulling interferometry provides the dynamic range needed for the detection of biomarkers. Formation flying provides the angular resolution required in the mid-infrared to separately distinguish the spectra of planets in multi-planet systems. The flight performance requirements for nulling have been met and must now be validated in a flight-like environment. Formation-flying algorithms have been demonstrated in the lab and must now be validated in space. Our proposed technology program is described. [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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