Abstract
Kernel-phase observables extracted from mid- to high-Strehl images are proving to be a powerful tool to probe within a few angular resolution elements of point sources. The attainable contrast is limited, however, by the dynamic range of the imaging sensors. The Fourier interpretation of images with pixels exposed beyond the saturation has so far been avoided. In cases where the image is dominated by the light of a point source, we show that we can use an interpolation to reconstruct the otherwise lost pixels with an accuracy sufficient to enable the extraction of kernel-phases from the patched image. We demonstrate the usability of our method by applying it to archive images of the Gl 494AB system taken with the Hubble Space Telescope in 1997. Using this new data point along with other resolved observations and radial velocity measurements, we produce improved constraints on the orbital parameters of the system, and consequently the masses of its components.
Highlights
The quest for the direct imaging of exoplanets has accelerated in recent years with the commissioning of extreme adaptive optics systems with coronagraphic capabilities, such as SPHERE (Beuzit et al 2008), GPI (Macintosh et al 2014), and SCExAO (Jovanovic et al 2015)
The planets discovered far by these instruments, have been detected at larger separations: Macintosh et al (2015) report a detection at ∼10λ/D (449 mas) and Chauvin et al (2017) at ∼20λ/D (830 mas). The performance of these coronagraphic devices at small angular separations is currently limited by the quality of the wavefront correction of the adaptive optics system, to which they are extremely sensitive (Guyon et al 2006)
In the case of saturation, the pixels to recover are clustered. Our approach tackles this problem in the image plane, and uses a synthetic point spread function (PSF) as a reference to interpolate the value of the saturated pixels, after which Fourier-phase values can be reliably extracted from these enhanced images
Summary
The quest for the direct imaging of exoplanets has accelerated in recent years with the commissioning of extreme adaptive optics systems with coronagraphic capabilities, such as SPHERE (Beuzit et al 2008), GPI (Macintosh et al 2014), and SCExAO (Jovanovic et al 2015) These instruments were designed to achieve high-contrast detections (104) at small angular separations (down to ∼2λ/D, where λ/D defines the resolution element, λ is the wavelength, and D is the telescope diameter). The planets discovered far by these instruments, have been detected at larger separations: Macintosh et al (2015) report a detection at ∼10λ/D (449 mas) and Chauvin et al (2017) at ∼20λ/D (830 mas) The performance of these coronagraphic devices at small angular separations is currently limited by the quality of the wavefront correction of the adaptive optics system, to which they are extremely sensitive (Guyon et al 2006).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
