Exoplanetary Science: An Overview

Santos, N. C.; Faria, J. P.

doi:10.1007/978-3-319-59315-9_9

Cited by 2 publications

(2 citation statements)

References 90 publications

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“…While the existence of magnetized stars has been known for quite a long time, there are little data about exoplanetary magnetic fields. They were discovered and estimated recently by indirect measurements based particularly on the observations of anomalous enhanced emissions ( in radio, UV, or X-ray) that likely indicate the existence of the magnetic field of exoplanets [3,51,52]. The irradiation of planet outer layers by star wind can lead to a substantial atmospheric outflow and therefore give the observable signatures for a distant observer (e.g., [53,54]).…”

Section: The Structure Of Astrosphere As the Possible Indication To Tmentioning

confidence: 99%

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Symmetries of Magnetic Fields Driven by Spherical Dynamos of Exoplanets and Their Host Stars

2020

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Observations of exoplanets open a new area of scientific activity and the structure of exoplanet magnetospheres is an important part of this area. Here we use symmetry arguments and experiences in spherical dynamo modeling to obtain the set of possible magnetic configurations for exoplanets and their corresponding host stars. The main part of our results is that the possible choice is much richer than the basic dipole magnetic field of both exoplanets and stars. Other options, for example, are quadrupole configurations or mixed parity solutions. Expected configurations of current sheets for the above mentioned exoplanet host star systems are presented as well.

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Section: The Structure Of Astrosphere As the Possible Indication To Tmentioning

confidence: 99%

“…Exoplanets is a new area for scientific investigations that accumulates ideas from various more traditional scientific branches [1][2][3][4]. The process of accumulation is far from being straightforward because of the novelty of the topic.…”

Section: Introductionmentioning

confidence: 99%

Symmetries of Magnetic Fields Driven by Spherical Dynamos of Exoplanets and Their Host Stars

2020

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A family of phase masks for broadband coronagraphy example of the wrapped vortex phase mask theory and laboratory demonstration

Galicher

Baudoz

Huby

et al. 2020

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Context. Future instruments need efficient coronagraphs over large spectral ranges to enable broadband imaging or spectral characterization of exoplanets that are 10 8 times fainter than their star. Several solutions have been proposed. Pupil apodizers can attenuate the star intensity by a factor of 10 10 but they only transmit a few percent of the light of the planet. Cascades of phase and/or amplitude masks can both attenuate the starlight and transmit most of the planet light, but the number of optics that require alignment makes this solution impractical for an instrument. Finally, vector phase masks can be used to detect faint sources close to bright stars but they require the use of high-quality circular polarizers and, as in the previous solution, this leads to a complex instrument with numerous optics that require alignment and stabilization. Aims. We propose simple coronagraphs that only need one scalar phase mask and one binary Lyot stop providing high transmission for the planet light (> 50 %) and high attenuation of the starlight over a large spectral bandpass (∼ 30 %) and a 360 • field-of-view. Methods. From mathematical considerations, we find a family of 2D phase masks optimized for an unobscured pupil. One mask is an azimuthal wrapped vortex phase ramp. We probe its coronagraphic performance using numerical simulations and laboratory tests. Results. From numerical simulations, we predict the wrapped vortex can attenuate the peak of the star image by a factor of 10 4 over a 29 % bandpass and 10 5 over a 18 % bandpass with transmission of more than 50 % of the planet flux at ∼ 4 λ/D. We confirm these predictions in the laboratory in visible light between 550 and 870 nm. We also obtain laboratory dark hole images in which exoplanets with fluxes that are 3.10 −8 times the host star flux could be detected at 3 σ. Conclusions. Taking advantage of a new technology for etching continuous 2D functions, a new type of mask can be easily manufactured opening up new possibilities for broadband coronagraphy.

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Exoplanetary Science: An Overview

Cited by 2 publications

References 90 publications

Symmetries of Magnetic Fields Driven by Spherical Dynamos of Exoplanets and Their Host Stars

Symmetries of Magnetic Fields Driven by Spherical Dynamos of Exoplanets and Their Host Stars

A family of phase masks for broadband coronagraphy example of the wrapped vortex phase mask theory and laboratory demonstration

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