A method to directly image exoplanets in multi-star systems such as Alpha-Centauri

Thomas, Sandrine; Belikov, Ruslan; Bendek, Eduardo

doi:10.1117/12.2188637

Cited by 3 publications

(3 citation statements)

References 11 publications

(12 reference statements)

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“…For high-contrast XAO systems, high-density DMs might be used to remove residual speckles seen in the science focal plane. In combination with the science focal plane detectors behind coronagraphs, a second stage AO system can be set-up in order to calibrate and remove residual speckles seen in the science images (Macintosh et al, 2006;Thomas et al, 2015).…”

Section: Wavefront Correction Devicesmentioning

confidence: 99%

Adaptive Optics for Extremely Large Telescopes

Hippler

2019

J. Astron. Instrum.

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Adaptive Optics (AO) has become a key technology for the largest ground-based telescopes currently under, or close to beginning of, construction. AO is an indispensable component and has basically only one task, that is to operate the telescope at its maximum angular resolution, without optical degradations resulting from atmospheric seeing. Based on three decades of experience using AO usually as an add-on component, all extremely large telescopes and their instrumentation are designed for di®raction limited observations from the very beginning. This paper illuminates various approaches of the ELT, the Giant Magellan Telescope (GMT), and the Thirty-Meter Telescope (TMT), to fully integrate AO in their designs. The paper concludes with a brief look into the requirements that high-contrast imaging poses on AO.

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Section: Wavefront Correction Devicesmentioning

confidence: 99%

Adaptive Optics for Extremely Large Telescopes

Hippler

2019

J. Astron. Instrum.

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“…It turns out that this is in fact possible with existing wavefront control systems, simply by applying a special algorithm. We briefly go over the principle here (for more details see [19,20]). Figure 5 shows a proof-of-principle simulation where for simplicity we assume a system with no coronagraph, in monochromatic light, and with one 32x32 deformable mirror.…”

Section: Multi-star Wavefront Controlmentioning

confidence: 99%

“…For example, the size of the dark zone can be made much larger and in theory can be as large as half the dark zone for a single star (to preserve the independent degrees of freedom available on the DM). The presence of a coronagraph or broadband light also does not affect the basic principles of this technique [20].…”

Section: Multi-star Wavefront Controlmentioning

confidence: 99%

How to directly image a habitable planet around Alpha Centauri with a ~30-45cm space telescope

et al. 2015

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Several mission concepts are being studied to directly image planets around nearby stars. It is commonly thought that directly imaging a potentially habitable exoplanet around a Sun-like star requires space telescopes with apertures of at least 1m. A notable exception to this is Alpha Centauri (A and B), which is an extreme outlier among FGKM stars in terms of apparent habitable zone size: the habitable zones are ~3x wider in apparent size than around any other FGKM star. This enables a ~30-45cm visible light space telescope equipped with a modern high performance coronagraph or starshade to resolve the habitable zone at high contrast and directly image any potentially habitable planet that may exist in the system. We presents a brief analysis of the astrophysical and technical challenges involved with direct imaging of Alpha Centauri with a small telescope and describe two new technologies that address some of the key technical challenges. In particular, the raw contrast requirements for such an instrument can be relaxed to 1e-8 if the mission spends 2 years collecting tens of thousands of images on the same target, enabling a factor of 500-1000 speckle suppression in post processing using a new technique called Orbital Difference Imaging (ODI). The raw light leak from both stars is controllable with a special wavefront control algorithm known as Multi-Star Wavefront Control (MSWC), which independently suppresses diffraction and aberrations from both stars using independent modes on the deformable mirror. We also show an example of a small coronagraphic mission concept to take advantage of this opportunity.

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Exomoons in Systems with a Strong Perturber: Applications to α Cen AB

Quarles

Eggl

Rosario-Franco

et al. 2021

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The presence of a stellar companion can place constraints on occurrence and orbital evolution of satellites orbiting exoplanets, i.e., exomoons. In this work we revise earlier orbital stability limits for retrograde orbits in the case of a three-body system consisting of a star, planet, and satellite. The revised limit reads a sat crit ≈ 0.668 ( 1 − 1.236 e p ) for e p ≤ 0.8 in units of the Hill Radius and represents the lower critical orbit as a function of the planetary eccentricity e p. A similar formula is determined for exomoons hosted by planets in binary star systems, where e p is replaced with the components of free and forced eccentricity from secular orbit evolution theory. By exploring the dynamics of putative exomoons in α Centauri AB we find that the outer stability limit can be much less than half the Hill Radius due to oscillations in the planetary orbital eccentricity caused by the gravitational interaction with the binary star. We show, furthermore, how the resulting truncation of the outer stability limit can affect the outward tidal migration and potential observability of exomoons through transit-timing variations (TTVs). Typical TTV (rms) amplitudes induced by exomoons in binary systems are ≲10 minutes and appear more likely for planets orbiting the less massive stellar component.

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A method to directly image exoplanets in multi-star systems such as Alpha-Centauri

Cited by 3 publications

References 11 publications

Adaptive Optics for Extremely Large Telescopes

Adaptive Optics for Extremely Large Telescopes

How to directly image a habitable planet around Alpha Centauri with a ~30-45cm space telescope

Exomoons in Systems with a Strong Perturber: Applications to α Cen AB

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