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See detailDynamical Evidence of a Spiral Arm-driving Planet in the MWC 758 Protoplanetary Disk
Ren, Bin; Dong, Ruobing; van Holstein, Rob G. et al

in Astrophysical Journal (2020), 898

More than a dozen young stars host spiral arms in their surrounding protoplanetary disks. The excitation mechanisms of such arms are under debate. The two leading hypotheses—companion-disk interaction and ... [more ▼]

More than a dozen young stars host spiral arms in their surrounding protoplanetary disks. The excitation mechanisms of such arms are under debate. The two leading hypotheses—companion-disk interaction and gravitational instability (GI)—predict distinct motion for spirals. By imaging the MWC 758 spiral arm system at two epochs spanning ∼5 yr using the SPHERE instrument on the Very Large Telescope, we test the two hypotheses for the first time. We find that the pattern speeds of the spirals are not consistent with the GI origin. Our measurements further evince the existence of a faint "missing planet" driving the disk arms. The average spiral pattern speed is 0°22 ± 0°03 yr[SUP]-1[/SUP], pointing to a driver at ${172}_{-14}^{+18}$ au around a 1.9 M[SUB]☉[/SUB] central star if it is on a circular orbit. In addition, we witness time-varying shadowing effects on a global scale that are likely originating from an inner disk. [less ▲]

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See detailKey Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument
Bailey, Vanessa P.; Armus, Lee; Balasubramanian, Bala et al

E-print/Working paper (2019)

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at ... [more ▼]

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post- processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures. <P /> [less ▲]

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See detailReview of high-contrast imaging systems for current and future ground-based and space-based telescopes: Part II. Common path wavefront sensing/control and coherent differential imaging
Jovanovic, Nemanja; Absil, Olivier ULiege; Baudoz, Pierre et al

in Close, L.; Schreiber, L.; Schmidt, D. (Eds.) Adaptive Optics Systems VI (2018, July 10)

The Optimal Optical Coronagraph (OOC) Workshop held at the Lorentz Center in September 2017 in Leiden, the Netherlands, gathered a diverse group of 25 researchers working on exoplanet instrumentation to ... [more ▼]

The Optimal Optical Coronagraph (OOC) Workshop held at the Lorentz Center in September 2017 in Leiden, the Netherlands, gathered a diverse group of 25 researchers working on exoplanet instrumentation to stimulate the emergence and sharing of new ideas. In this second installment of a series of three papers summarizing the outcomes of the OOC workshop, we present an overview of common path wavefront sensing/control and Coherent Differential Imaging techniques, highlight the latest results, and expose their relative strengths and weaknesses. We layout critical milestones for the field with the aim of enhancing future ground/space based high contrast imaging platforms. Techniques like these will help to bridge the daunting contrast gap required to image a terrestrial planet in the zone where it can retain liquid water, in reflected light around a G type star from space. [less ▲]

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See detailReview of high-contrast imaging systems for current and future ground-based and space-based telescopes III: technology opportunities and pathways
Snik, Frans; Absil, Olivier ULiege; Baudoz, Pierre et al

in Navarro, R.; Geyl, R. (Eds.) Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III (2018, July 10)

The Optimal Optical CoronagraphWorkshop at the Lorentz Center in September 2017 in Leiden, the Netherlands gathered a diverse group of 30 researchers working on exoplanet instrumentation to stimulate the ... [more ▼]

The Optimal Optical CoronagraphWorkshop at the Lorentz Center in September 2017 in Leiden, the Netherlands gathered a diverse group of 30 researchers working on exoplanet instrumentation to stimulate the emergence and sharing of new ideas. This contribution is the final part of a series of three papers summarizing the outcomes of the workshop, and presents an overview of novel optical technologies and systems that are implemented or considered for high-contrast imaging instruments on both ground-based and space telescopes. The overall objective of high contrast instruments is to provide direct observations and characterizations of exoplanets at contrast levels as extreme as 10[SUP]-10[/SUP]. We list shortcomings of current technologies, and identify opportunities and development paths for new technologies that enable quantum leaps in performance. Specifically, we discuss the design and manufacturing of key components like advanced deformable mirrors and coronagraphic optics, and their amalgamation in "adaptive coronagraph" systems. Moreover, we discuss highly integrated system designs that combine contrast-enhancing techniques and characterization techniques (like high-resolution spectroscopy) while minimizing the overall complexity. Finally, we explore extreme implementations using all-photonics solutions for ground-based telescopes and dedicated huge apertures for space telescopes. [less ▲]

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See detailCHIPS: The Carina High-contrast Imaging Project of massive Stars
Rainot, Alan; Sana, Hugues; Gomez-Gonzalez, Carlos A. et al

in Elridge, J; Bray, J; McClelland, L (Eds.) et al Proceedings IAU Symposium No. 329 (2017, July 28)

The formation of massive stars remains one of the most intriguing questions in astrophysics today. The main limitations result from the difficulty to obtain direct observational constraints on the ... [more ▼]

The formation of massive stars remains one of the most intriguing questions in astrophysics today. The main limitations result from the difficulty to obtain direct observational constraints on the formation process itself. In this context, the Carina High-contrast Imaging Project of massive Stars (CHIPS) aims to observe all 80+ O stars in the Carina nebula using the new VLT 2nd-generation extreme-AO instrument SPHERE. This instrument offers unprecedented imaging contrast allowing us to detect the faintest companions around massive stars. These novel observational constraints will help to discriminate between the different formation scenarios by comparing their predictions for companion statistics and properties. [less ▲]

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See detailVLT/SPHERE robust astrometry of the HR8799 planets at milliarcsecond-level accuracy. Orbital architecture analysis with PyAstrOFit
Wertz, Olivier; Absil, Olivier ULiege; Gómez González, Carlos ULiege et al

in Astronomy and Astrophysics (2017), 598

HR8799 is orbited by at least four giant planets, making it a prime target for the recently commissioned Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT/SPHERE). As such, it was observed on ... [more ▼]

HR8799 is orbited by at least four giant planets, making it a prime target for the recently commissioned Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT/SPHERE). As such, it was observed on five consecutive nights during the SPHERE science verification in December 2014. We aim to take full advantage of the SPHERE capabilities to derive accurate astrometric measurements based on H-band images acquired with the Infra-Red Dual-band Imaging and Spectroscopy (IRDIS) subsystem, and to explore the ultimate astrometric performance of SPHERE in this observing mode. We also aim to present a detailed analysis of the orbital parameters for the four planets. We report the astrometric positions for epoch 2014.93 with an accuracy down to 2.0 mas, mainly limited by the astrometric calibration of IRDIS. For each planet, we derive the posterior probability density functions for the six Keplerian elements and identify sets of highly probable orbits. For planet d, there is clear evidence for nonzero eccentricity ($e \simeq 0.35$), without completely excluding solutions with smaller eccentricities. The three other planets are consistent with circular orbits, although their probability distributions spread beyond $e = 0.2$, and show a peak at $e \simeq 0.1$ for planet e. The four planets have consistent inclinations of about $30\deg$ with respect to the sky plane, but the confidence intervals for the longitude of ascending node are disjoint for planets b and c, and we find tentative evidence for non-coplanarity between planets b and c at the $2 \sigma$ level. [less ▲]

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See detailThe SHARDDS survey: First resolved image of the HD 114082 debris disk in the Lower Centaurus Crux with SPHERE
Wahhaj, Zahed; Milli, Julien; Kennedy, Grant et al

in Astronomy and Astrophysics (2016), 596

We present the first resolved image of the debris disk around the 16 ± 8 Myr old star, HD 114082. The observation was made in the H-band using the SPHERE instrument. The star is at a distance of 92 ± 6 pc ... [more ▼]

We present the first resolved image of the debris disk around the 16 ± 8 Myr old star, HD 114082. The observation was made in the H-band using the SPHERE instrument. The star is at a distance of 92 ± 6 pc in the Lower Centaurus Crux association. Using a Markov chain Monte Carlo analysis, we determined that the debris is likely in the form of a dust ring with an inner edge of 27.7[SUP]+2.8[/SUP][SUB]-3.5[/SUB] au, position angle -74.3°[SUP]+0.5[/SUP][SUB]-1.5[/SUB], and an inclination with respect to the line of sight of 6.7°[SUP]+3.8[/SUP][SUB]-0.4[/SUB]. The disk imaged in scattered light has a surface density that is declining with radius of r[SUP]-4[/SUP], which is steeper than expected for grain blowout by radiation pressure. We find only marginal evidence (2σ) of eccentricity and rule out planets more massive than 1.0 M[SUB]Jup[/SUB] orbiting within 1 au of the inner edge of the ring, since such a planet would have disrupted the disk. The disk has roughly the same fractional disk luminosity (L[SUB]disk[/SUB]/L[SUB]∗[/SUB] = 3.3 × 10[SUP]-3[/SUP]) as HR 4796 A and β Pictoris, however it was not detected by previous instrument facilities most likely because of its small angular size (radius 0.4''), low albedo ( 0.2), and low scattering efficiency far from the star due to high scattering anisotropy. With the arrival of extreme adaptive optics systems, such as SPHERE and GPI, the morphology of smaller, fainter, and more distant debris disks are being revealed, providing clues to planet-disk interactions in young protoplanetary systems. The reduced images are only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/L4">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/L4</A> [less ▲]

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See detailDiscovery of a Companion Candidate in the HD 169142 Transition Disk and the Possibility of Multiple Planet Formation
Reggiani, Maddalena ULiege; Quanz, Sascha P.; Meyer, Michael R. et al

in Astrophysical Journal. Letters (2014), 792

We present L'- and J-band high-contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively. A source located ... [more ▼]

We present L'- and J-band high-contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively. A source located at 0.''156 ± 0.''032 north of the host star (P.A. = 7.4° ± 11.3°) appears in the final reduced L' image. At the distance of the star (~145 pc), this angular separation corresponds to a physical separation of 22.7 ± 4.7 AU, locating the source within the recently resolved inner cavity of the transition disk. The source has a brightness of L' = 12.2 ± 0.5 mag, whereas it is not detected in the J band (J >13.8 mag). If its L' brightness arose solely from the photosphere of a companion and given the J - L' color constraints, it would correspond to a 28-32 MJup object at the age of the star, according to the COND models. Ongoing accretion activity of the star suggests, however, that gas is left in the inner disk cavity from which the companion could also be accreting. In this case, the object could be lower in mass and its luminosity enhanced by the accretion process and by a circumplanetary disk. A lower-mass object is more consistent with the observed cavity width. Finally, the observations enable us to place an upper limit on the L'-band flux of a second companion candidate orbiting in the disk annular gap at ~50 AU, as suggested by millimeter observations. If the second companion is also confirmed, HD 169142 might be forming a planetary system, with at least two companions opening gaps and possibly interacting with each other. [less ▲]

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See detailTaking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe
Mawet, Dimitri; Murakami, Naoshi; Delacroix, Christian ULiege et al

in Shaklan, Stuart (Ed.) Techniques and Instrumentation for Detection of Exoplanets V. (2011, September 01)

The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground- and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at ... [more ▼]

The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground- and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at Palomar and in the laboratory at JPL, and Hokkaido University. Manufacturing technologies for devices covering wavelength ranges from the optical to the mid-infrared, have been maturing quickly. We will review the current status of technology developments supported by NASA in the USA (Jet Propulsion Laboratory-California Institute of Technology, University of Arizona, JDSU and BEAMCo), Europe (University of Li`ege, Observatoire de Paris- Meudon, University of Uppsala) and Japan (Hokkaido University, and Photonics Lattice Inc.), using liquid crystal polymers, subwavelength gratings, and photonics crystals, respectively. We will then browse concrete perspectives for the use of the VVC on upcoming ground-based facilities with or without (extreme) adaptive optics, extremely large ground-based telescopes, and space-based internal coronagraphs. [less ▲]

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