ORCID Profile
0000-0003-1180-4138
Current Organisation
Observatoire de la Côte d'Azur
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Stellar Astronomy and Planetary Systems | Astronomical and Space Sciences | Cosmology and Extragalactic Astronomy | Astronomical and Space Instrumentation
Expanding Knowledge in the Physical Sciences | Scientific Instruments |
Publisher: Oxford University Press (OUP)
Date: 28-03-2019
DOI: 10.1093/MNRAS/STZ882
Publisher: SPIE
Date: 13-07-2018
DOI: 10.1117/12.2314282
Publisher: American Astronomical Society
Date: 09-08-2012
Publisher: American Astronomical Society
Date: 04-05-2010
Publisher: The Optical Society
Date: 06-10-2017
DOI: 10.1364/OE.25.025546
Publisher: SPIE
Date: 22-08-2012
DOI: 10.1117/12.925565
Publisher: American Astronomical Society
Date: 04-2023
Abstract: We report the discovery of the first brown dwarf binary system with a Y dwarf primary, WISE J033605.05−014350.4, observed with NIRCam on JWST with the F150W and F480M filters. We employed an empirical point-spread function binary model to identify the companion, located at a projected separation of 0.″084, position angle of 295°, and with contrasts of 2.8 and 1.8 mag in F150W and F480M, respectively. At a distance of 10 pc based on its Spitzer parallax, and assuming a random inclination distribution, the physical separation is approximately 1 au. Evolutionary models predict for that an age of 1–5 Gyr, the companion mass is about 4–12.5 Jupiter masses around the 7.5–20 Jupiter mass primary, corresponding to a companion-to-host mass fraction of q = 0.61 ± 0.05. Under the assumption of a Keplerian orbit the period for this extreme binary is in the range of 5–9 yr. The system joins a small but growing s le of ultracool dwarf binaries with effective temperatures of a few hundreds of Kelvin. Brown dwarf binaries lie at the nexus of importance for understanding the formation mechanisms of these elusive objects, as they allow us to investigate whether the companions formed as stars or as planets in a disk around the primary.
Publisher: SPIE
Date: 24-07-2014
DOI: 10.1117/12.2057210
Publisher: Oxford University Press (OUP)
Date: 17-11-2015
Publisher: Oxford University Press (OUP)
Date: 08-03-2014
DOI: 10.1093/MNRAS/STU218
Publisher: American Astronomical Society
Date: 20-05-2007
DOI: 10.1086/513868
Publisher: American Astronomical Society
Date: 02-04-2013
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.858116
Publisher: IOP Publishing
Date: 08-11-2016
Publisher: American Astronomical Society
Date: 21-12-2010
Publisher: SPIE
Date: 02-08-2014
DOI: 10.1117/12.2056639
Publisher: EDP Sciences
Date: 08-2017
Publisher: American Astronomical Society
Date: 20-05-2008
DOI: 10.1086/587435
Publisher: SPIE
Date: 20-08-2009
DOI: 10.1117/12.826633
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.857915
Publisher: The Optical Society
Date: 17-07-2017
DOI: 10.1364/OE.25.017753
Publisher: SPIE
Date: 03-08-2016
DOI: 10.1117/12.2234299
Publisher: SPIE
Date: 26-07-2016
DOI: 10.1117/12.2234294
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.857878
Publisher: American Astronomical Society
Date: 20-12-2012
Publisher: IOP Publishing
Date: 12-2011
DOI: 10.1086/663723
Publisher: EDP Sciences
Date: 10-2020
DOI: 10.1051/0004-6361/202038866
Abstract: Context. The use of interferometric nulling for the direct detection of extrasolar planets is in part limited by the extreme sensitivity of the instrumental response to tiny optical path differences between apertures. The recently proposed kernel-nuller architecture attempts to alleviate this effect with an all-in-one combiner design that enables the production of observables inherently robust to residual optical path differences (≪ λ ). Aims. To date, a unique kernel-nuller design has been proposed ad hoc for a four-beam combiner. We examine the properties of this original design and generalize them for an arbitrary number of apertures. Methods. We introduce a convenient graphical representation of the complex combiner matrices that model the kernel nuller and highlight the symmetry properties that enable the formation of kernel nulls. The analytical description of the nulled outputs we provide demonstrates the properties of a kernel nuller. Results. Our description helps outline a systematic way to build a kernel nuller for an arbitrary number of apertures. The designs for three- and six-input combiners are presented along with the original four-input concept. The combiner grows in complexity with the square of the number of apertures. While one can mitigate this complexity by multiplexing nullers working independently over a smaller number of sub-apertures, an all-in-one kernel nuller recombining a large number of apertures appears as the most efficient way to characterize a high-contrast complex astrophysical scene. Conclusions. Kernel nullers can be designed for an arbitrary number of apertures that produce observable quantities robust to residual perturbations. The designs we recommend are lossless and take full advantage of all the available interferometric baselines. They are complete, result in as many kernel nulls as the theoretically expected number of closure-phases, and are optimized to require the smallest possible number of outputs.
Publisher: American Astronomical Society
Date: 09-09-2020
Publisher: Oxford University Press (OUP)
Date: 17-08-2020
Abstract: Direct imaging in the infrared at the diffraction limit of large telescopes is a unique probe of the properties of young planetary systems. We survey 55 single class I and class II stars in Taurus in the L’ filter using natural and laser guide star adaptive optics and the near-infrared camera (NIRC2) of the Keck II telescope, in order to search for planetary-mass companions. We use both reference star differential imaging and kernel phase techniques, achieving typical 5σ contrasts of ∼6 mag at separations of 0.2 arcsec and ∼8 mag beyond 0.5 arcsec. Although, we do not detect any new faint companions, we constrain the frequency of wide separation massive planets, such as HR 8799 analogues. We find that, assuming hot-start models and a planet distribution with power-law mass and semimajor axis indices of −0.5 and −1, respectively, less than 20 per cent of our target stars host planets with masses & MJ at separations & au.
Publisher: EDP Sciences
Date: 11-2018
DOI: 10.1051/0004-6361/201832847
Abstract: Context. Combining the resolving power of long-baseline interferometry with the high-dynamic range capability of nulling still remains the only technique that can directly sense the presence of structures in the innermost regions of extrasolar planetary systems. Aims. Ultimately, the performance of any nuller architecture is constrained by the partial resolution of the on-axis star whose light it attempts to cancel out. However from the ground, the effective performance of nulling is dominated by residual time-varying instrumental phase and background errors that keep the instrument off the null. Our work investigates robustness against instrumental phase. Methods. We introduce a modified nuller architecture that enables the extraction of information that is robust against piston excursions. Our method generalizes the concept of kernel, now applied to the outputs of the modified nuller so as to make them robust to second order pupil phase error. We present the general method to determine these kernel-outputs and highlight the benefits of this novel approach. Results. We present the properties of VIKiNG: the VLTI Infrared Kernel NullinG, an instrument concept within the Hi-5 framework for the 4-UT VLTI infrastructure that takes advantage of the proposed architecture, to produce three self-calibrating nulled outputs. Conclusions. Stabilized by a fringe-tracker that would bring piston-excursions down to 50 nm, this instrument would be able to directly detect more than a dozen extrasolar planets so-far detected by radial velocity only, as well as many hot transiting planets and a significant number of very young exoplanets.
Publisher: American Astronomical Society
Date: 07-04-2009
Publisher: AIP
Date: 2009
DOI: 10.1063/1.3099145
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.858161
Publisher: SPIE
Date: 12-09-2012
DOI: 10.1117/12.925838
Publisher: American Astronomical Society
Date: 20-09-2006
DOI: 10.1086/506192
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.857874
Publisher: American Astronomical Society
Date: 17-03-2011
Publisher: American Astronomical Society
Date: 21-12-2010
Publisher: American Astronomical Society
Date: 05-2008
DOI: 10.1086/529578
Publisher: American Astronomical Society
Date: 28-12-2011
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-04-2023
Abstract: Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures of planetary systems. However, few planets have been detected in blind surveys with direct imaging. Using astrometry from the Gaia and Hipparcos spacecraft, we identified dynamical evidence for a gas giant planet around the nearby star HIP 99770. We confirmed the detection of this planet with direct imaging using the Subaru Coronagraphic Extreme Adaptive Optics instrument. The planet, HIP 99770 b, orbits 17 astronomical units from its host star, receiving an amount of light similar to that reaching Jupiter. Its dynamical mass is 13.9 to 16.1 Jupiter masses. The planet-to-star mass ratio [(7 to 8) × 10 −3 ] is similar to that of other directly imaged planets. The planet’s atmospheric spectrum indicates an older, less cloudy analog of the previously imaged exoplanets around HR 8799.
Publisher: American Astronomical Society
Date: 10-10-2006
DOI: 10.1086/508771
Start Date: 11-2022
End Date: 11-2024
Amount: $770,000.00
Funder: Australian Research Council
View Funded Activity