The first images from optical aperture synthesis

Haniff, Christopher A.; Mackay, Craig D.; Titterington, D.; Sivia, D.S.; Baldwin, John E.; Warner, P. J.

doi:10.1038/328694a0

Cited by 128 publications

(100 citation statements)

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“…The resulting interference fringes were imaged onto a CCD and one-dimensional fringe snapshots were recorded at 12-ms intervals. For each orientation of the mask, the fringe data were reduced using standard procedures (Haniff et al 1987;Buscher et al 1990) to provide estimates of the visibility amplitudes on all 10 interferometer baselines and the closure phases on the 10 (linear) triangles of baselines. As for the COAST measurements, the uncertainties in the visibility amplitudes were dominated by calibration errors, which in this instance were unusually large (fractional error ∼30%).…”

Section: Wht Data From 1997mentioning

confidence: 99%

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Radiative hydrodynamics simulations of red supergiant stars

Chiavassa

Haubois

Young

et al. 2010

A&A

125

130

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Context. The red supergiant (RSG) Betelgeuse is an irregular variable star. Convection may play an important role in understanding this variability. Interferometric observations can be interpreted using sophisticated simulations of stellar convection. Aims. We compare the visibility curves and closure phases obtained from our 3D simulation of RSG convection with CO5BOLD to various interferometric observations of Betelgeuse from the optical to the H band to characterize and measure the convection pattern on this star. Methods. We use a 3D radiative-hydrodynamics (RHD) simulation to compute intensity maps in different filters and thus derive interferometric observables using the post-processing radiative transfer code OPTIM3D. The synthetic visibility curves and closure phases are compared to observations. Results. We provide a robust detection of the granulation pattern on the surface of Betelgeuse in both the optical and the H band based on excellent fits to the observed visibility points and closure phases. We determine that the Betelgeuse surface in the H band is covered by small to medium scale (5−15 mas) convection-related surface structures and a large (≈30 mas) convective cell. In this spectral region, H 2 O molecules are the main absorbers and contribute to both the small structures and the position of the first null of the visibility curve (i.e., the apparent stellar radius).

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Section: Wht Data From 1997mentioning

confidence: 99%

“…The observations performed with the WHT used the nonredundant aperture masking method (Baldwin et al 1986;Haniff et al 1987) and employed a five-hole linear aperture mask. Filters centred on both 7000 Å and 9050 Å were used to select the observing waveband; only the 7000 Å data are presented in this paper.…”

Section: Wht Data From 1997mentioning

confidence: 99%

Radiative hydrodynamics simulations of red supergiant stars

Chiavassa

Haubois

Young

et al. 2010

A&A

125

130

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“…We are able to place upper limits on additional massive companions to the HR 8799 system that would otherwise have been veiled by the telescope diffraction or the associated uncorrected quasi-static speckle noise (e.g. Hinkley et al 2007) using more conventional direct imaging techniques. Hinkley et al (2011c).…”

Section: Aperture Masking Interferometrymentioning

confidence: 99%

“…Together, these two techniques can obtain contrast levels of 10 4 -10 5 at 1 (Leconte 184 S. Hinkley et al 2010). Improvements in coronagraphy, specifically the apodization of the telescope pupil (Soummer 2005), as well as post-processing to suppress speckle noise (Hinkley et al 2007, Crepp et al 2011, can significantly improve the achieved contrast, especially at high Strehl ratios. Below we briefly describe some of the instrumentation being built at the time of this writing, or currently in place on large telescopes.…”

Section: The Challenge Of High Contrast Imagingmentioning

confidence: 99%

Adaptive Optics Observations of Exoplanets, Brown Dwarfs, and Binary Stars

Hinkley¹

2011

Proc. IAU

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Abstract. The current direct observations of brown dwarfs and exoplanets have been obtained using instruments not specifically designed for overcoming the large contrast ratio between the host star and any wide-separation faint companions. However, we are about to witness the birth of several new dedicated observing platforms specifically geared towards high contrast imaging of these objects. The Gemini Planet Imager, VLT-SPHERE, Subaru HiCIAO, and Project 1640 at the Palomar 5m telescope will return images of numerous exoplanets and brown dwarfs over hundreds of observing nights in the next five years. Along with diffraction-limited coronagraphs and high-order adaptive optics, these instruments also will return spectral and polarimetric information on any discovered targets, giving clues to their atmospheric compositions and characteristics. Such spectral characterization will be key to forming a detailed theory of comparative exoplanetary science which will be widely applicable to both exoplanets and brown dwarfs. Further, the prevalence of aperture masking interferometry in the field of high contrast imaging is also allowing observers to sense massive, young planets at solar system scales (∼3-30 AU)-separations out of reach to conventional direct imaging techniques. Such observations can provide snapshots at the earliest phases of planet formation-information essential for constraining formation mechanisms as well as evolutionary models of planetary mass companions. As a demonstration of the power of this technique, I briefly review recent aperture masking observations of the HR 8799 system. Moreover, all of the aforementioned techniques are already extremely adept at detecting low-mass stellar companions to their target stars, and I present some recent highlights.

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“…Speckle interferometry (Labeyrie 1970) is well suited to detecting binaries but provides restricted dynamic range at short separations. Aperture masking (Haniff et al 1987) is another solution exploiting short exposure images obtained through a mask with holes (sub-apertures) placed in the pupil plane in order to remove the noise due to atmospheric perturbations. This technique has established itself as the standard for high resolution imaging with contrast ratios on the order of 10 −3 at λ/D (Hinkley et al 2011).…”

Section: Introductionmentioning

confidence: 99%

FIRST, a fibered aperture masking instrument

Huby¹,

Perrin²,

Marchis³

et al. 2012

A&A

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Aims. In this paper we present the first on-sky results with the fibered aperture masking instrument FIRST. Its principle relies on the combination of spatial filtering and aperture masking using single-mode fibers, a novel technique that is aimed at high dynamic range imaging with high angular resolution. Methods. The prototype has been tested with the Shane 3-m telescope at Lick Observatory. The entrance pupil is divided into subpupils feeding single-mode fibers. The flux injection into the fibers is optimized by a segmented mirror. The beams are spectrally dispersed and recombined in a non-redundant exit configuration in order to retrieve all contrasts and phases independently. Results. The instrument works at visible wavelengths between 600 nm and 760 nm and currently uses nine of the 30 43 cm subapertures constituting the full pupil. First fringes were obtained on Vega and Deneb. Stable closure phases were measured with standard deviations on the order of 1 degree. Closure phase precision can be further improved by addressing some of the remaining sources of systematic errors. While the number of fibers used in the experiment was too small to reliably estimate visibility amplitudes, we have measured closure amplitudes with a precision of 10% in the best case. Conclusions. These first promising results obtained under real observing conditions validate the concept of the fibered aperture masking instrument and open the way for a new type of ground-based instrument working in the visible. The next steps of the development will be to improve the stability and the sensitivity of the instrument in order to achieve more accurate closure phase and visibility measurements, and to increase the number of sub-pupils to reach full pupil coverage.

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The first images from optical aperture synthesis

Cited by 128 publications

References 0 publications

Radiative hydrodynamics simulations of red supergiant stars

Radiative hydrodynamics simulations of red supergiant stars

Adaptive Optics Observations of Exoplanets, Brown Dwarfs, and Binary Stars

FIRST, a fibered aperture masking instrument

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