scispace - formally typeset
Open AccessJournal ArticleDOI

Temporal Evolution of Coronagraphic Dynamic Range and Constraints on Companions to Vega

Reads0
Chats0
TLDR
In this paper, a series of 284 8 s, AO-corrected, coronagraphically occulted H-band images of the star Vega at the 3.63 m AEOS telescope was obtained for studying the temporal behavior of speckle noise and represents the first time such a study on highly corrected coronagraphic AO images has been carried out in a quantitative way.
Abstract
The major obstacle to the direct detection of companions to nearby stars is the overwhelming brightness of the host star. Current instruments employing the combination of adaptive optics (AO) and coronagraphy can typically detect objects within 2'' of the star that are ~104-105 times fainter. Correlated speckle noise is one of the biggest obstacles limiting such high-contrast imaging. We have obtained a series of 284 8 s, AO-corrected, coronagraphically occulted H-band images of the star Vega at the 3.63 m AEOS telescope located on Haleakala, Hawaii. This data set is unique for studying the temporal behavior of speckle noise and represents the first time such a study on highly corrected coronagraphic AO images has been carried out in a quantitative way. We find the speckle pattern to be highly stable in both position and time in our data. This is due to the fact that the AO system corrects disturbances to the stellar wave front at the level where the instrumental wave front errors dominate. Because of this, we find that our detection limit is not significantly improved simply with increased exposure time alone. However, we are able to improve our dynamic range by 1.5-2 mag through subtraction of static/quasi-static speckles in two rotating frames: the telescope pupil frame and the deformable mirror frame. The highly stable nature of speckles will exist for any program using coronagraphy and high-order AO. Furthermore, from our data, we are able to constrain the mass of any purported companion to Vega to be less than ~45MJ at 8 AU and less than ~30MJ at 16 AU, radii not previously probed at these sensitivities.

read more

Citations
More filters
Journal ArticleDOI

First light of the Gemini Planet Imager

TL;DR: Observations ofBeta Pictoris clearly detect the planet, Beta Pictoris b, in a single 60-s exposure with minimal postprocessing, and fitting the Keplerian orbit of Beta Pic b using the new position together with previous astrometry gives a factor of 3 improvement in most parameters over previous solutions.
Journal ArticleDOI

Imaging Extrasolar Giant Planets

TL;DR: In this paper, a review of recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments is presented.
Journal ArticleDOI

Fundamental limitations of high contrast imaging set by small sample statistics

TL;DR: In this article, the impact of small sample statistics on detection thresholds and corresponding confidence levels (CLs) in high-contrast imaging at small angles is reviewed. But the authors do not consider the effect of small angles on the detection threshold.
Journal ArticleDOI

Photometric characterization of exoplanets using angular and spectral differential imaging

TL;DR: In this article, the authors investigate the photometric error and the consequences on the determination of the physical parameters of the detected planets and apply this empirical accuracy to study the characterization capabilities of a high-contrast differential imager.
References
More filters
Journal ArticleDOI

Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458

TL;DR: In this article, the authors present evolutionary models for cool brown dwarfs and extra-solar giant planets and show that irradiation effects can substantially affect the radius of sub-jovian mass giant planets.
Journal ArticleDOI

Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 20945

TL;DR: In this article, the authors present evolutionary models for cool brown dwarfs and extra-solar giant planets and show that irradiation effects can substantially affect the radius of sub-jovian mass giant planets.
Journal ArticleDOI

Angular Differential Imaging: a Powerful High-Contrast Imaging Technique

TL;DR: In this paper, the authors proposed an acquisition strategy and reduction pipeline for speckle attenuation and high contrast imaging is demonstrated to significantly get better detection limits with longer integration times at all angular separations.
Related Papers (5)