Lock-In Image Subtraction: Detectability of Circumstellar Planets with the Large Space Telescope

Bonneau, Dominique; Josse, Michel A.; Labeyrie, A.

doi:10.1007/978-94-010-1881-4_52

Cited by 14 publications

(13 citation statements)

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“…Coronagraphy, invented by Lyot (1930Lyot ( , 1939 for the observation of the solar corona, is the first recognized technique to provide direct imaging capabilities of exoplanets (Bonneau et al 1975;Malbet 1996;Watson et al 1991). The technique has been recently improved by the use of a π Phase Mask (PM) instead of the Lyot's opaque mask.…”

Section: Introductionmentioning

confidence: 99%

Interferometric apodization of rectangular apertures

Aime¹,

Soummer²,

Ferrari³

2001

A&A

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Abstract. We describe the principle of an apodization technique for rectangular apertures that can be implemented using a Michelson or a Mach-Zender interferometer. Using several interferometers, any integer power of cosine functions can be obtained. The technique is considered for application to the Apodized Square Aperture (ASA) concept recently proposed by Nisenson & Papaliolios (2001). Simple analytic expressions for the Point Spread Functions of such apodized apertures are given. For a cosine to the power N apodization, the resulting focal plane amplitude is simply the sum of N + 1 weighted and shifted sine cardinal functions. The interest of such apodized apertures for coronagraphy is investigated. It appears that these apodization functions are very efficient provided that only a central part of the cosine-arch is used. Analytic expressions are derived for the residual amplitude left in an image of the aperture after the coronagraphic experiment. Best results are obtained with a cosine squared apodization.

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Section: Introductionmentioning

confidence: 99%

Interferometric apodization of rectangular apertures

Aime¹,

Soummer²,

Ferrari³

2001

A&A

View full text Add to dashboard Cite

show abstract

“…The interest in stellar coronagraphy is relatively recent (Bonneau et al 1975;Smith & Terrile 1984;Malbet 1996;Beuzit et al 1997;Mouillet et al 1997), and nowadays mainly stimulated by the exoplanets searches. The direct imaging of an exoplanet is the most exciting objective for high contrast imaging techniques: it will provide valuable information such as its mass (removing the ambiguity due to the radial velocities technique), its albedo and its atmosphere chemical composition if spectral information can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Stellar coronagraphy with prolate apodized circular apertures

Soummer¹,

Aime²,

Falloon³

2003

A&A

154

188

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Abstract. This paper generalizes to circular apertures the theoretical study of stellar coronagraphy with prolate apodized rectangular entrance apertures of Aime et al. (2002). The main difference between the two studies is that circular prolate spheroidal functions are used for a circular aperture instead of linear prolate spheroidal functions for rectangular apertures. Owing to the radial property of the problem, the solution to the general equation for coronagraphy is solved using a Hankel transform instead of a product of Fourier transforms in the rectangular case. This new theoretical study permits a better understanding of coronagraphy, stressing the importance of entrance pupil apodization. A comparison with the classical unapodized Lyot technique is performed: a typical gain of 10 4 to 10 6 can be obtained theoretically with this technique. Circular and rectangular apertures give overall comparable results: a total extinction of the star light is obtained for Roddier & Roddier's phase mask technique whilst optimal starlight rejections are obtained with a Lyot opaque mask. A precise comparison between a circular aperture and a square aperture of same surface favors the use of a circular aperture for detection of extrasolar planets.

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“…The interest in Stellar Coronagraphy arose later, for the study of the vicinity of stars (Bonneau et al 1975;Smith & Terrile 1984;Malbet 1996;Mouillet 1997;Beuzit et al 1997;Mouillet et al 1997). Nowadays, coronagraphy is mainly studied for the direct detection of exoplanets, which is principally limited by the intensity ratio between the star and the planet, roughly of 10 6 in the infrared, and up to 10 9 in the visible.…”

Section: Introductionmentioning

confidence: 99%

Total coronagraphic extinction of rectangular apertures using linear prolate apodizations

Aime¹,

Soummer²,

Ferrari³

2002

A&A

112

151

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Abstract. This paper presents a theoretical study of stellar coronagraphy with apodized entrance apertures. The study is restricted to a perfect telescope operating in space, and a monochromatic on-axis unresolved star. It is shown that linear prolate functions are the optimal apodizers for rectangular apertures in stellar coronagraphy. With the phase mask technique (Roddier & Roddier 1997), prolate functions can produce a total extinction of the star light. For Lyot's coronagraphy, the extinction is not complete, but prolate apodizations lead to an optimal star residual intensity with surprising interesting properties: the residual star light and the planet enjoy the same apodized intensity pattern (but different dynamic) with the optimal light concentration. With this technique, very high rejection rates can be obtained for Lyot's coronagraphy, with smaller mask sizes.

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Lock-In Image Subtraction: Detectability of Circumstellar Planets with the Large Space Telescope

Cited by 14 publications

References 0 publications

Interferometric apodization of rectangular apertures

Interferometric apodization of rectangular apertures

Stellar coronagraphy with prolate apodized circular apertures

Total coronagraphic extinction of rectangular apertures using linear prolate apodizations

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