Adaptive optics for direct detection of extrasolar planets: the Gemini Planet Imager

Context. The observation of planets in their formation stage is a crucial but very challenging step in understanding when, how, and where planets form. PDS 70 is a young pre-main sequence star surrounded by a transition disk, in the gap of which a planetary-mass companion has recently been discovered. This discovery represents the first robust direct detection of such a young planet, possibly still at the stage of formation. Aims. We aim to characterize the orbital and atmospheric properties of PDS 70 b, which was first identified on May 2015 in the course of the SHINE survey with SPHERE, the extreme adaptive-optics instrument at the VLT. Methods. We obtained new deep SPHERE/IRDIS imaging and SPHERE/IFS spectroscopic observations of PDS 70 b. The astrometric baseline now covers 6 yr, which allowed us to perform an orbital analysis. For the first time, we present spectrophotometry of the young planet which covers almost the entire near-infrared range (0.96–3.8 μm). We use different atmospheric models covering a large parameter space in temperature, log g, chemical composition, and cloud properties to characterize the properties of the atmosphere of PDS 70 b. Results. PDS 70 b is most likely orbiting the star on a circular and disk coplanar orbit at ~22 au inside the gap of the disk. We find a range of models that can describe the spectrophotometric data reasonably well in the temperature range 1000–1600 K and log g no larger than 3.5 dex. The planet radius covers a relatively large range between 1.4 and 3.7 RJ with the larger radii being higher than expected from planet evolution models for the age of the planet of 5.4 Myr. Conclusions. This study provides a comprehensive data set on the orbital motion of PDS 70 b, indicating a circular orbit and a motion coplanar with the disk. The first detailed spectral energy distribution of PDS 70 b indicates a temperature typical of young giant planets. The detailed atmospheric analysis indicates that a circumplanetary disk may contribute to the total planetflux.

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Direct Detection of the Brown Dwarf GJ 802B with Adaptive Optics Masking Interferometry

The Astrophysical Journal ◽

10.1086/508771 ◽

2006 ◽

Vol 650 (2) ◽

pp. L131-L134 ◽

Cited By ~ 41

Author(s):

James P. Lloyd ◽

Frantz Martinache ◽

Michael J. Ireland ◽

John D. Monnier ◽

Steven H. Pravdo ◽

...

Keyword(s):

Adaptive Optics ◽

Direct Detection ◽

Brown Dwarf

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Direct detection and characterization of extrasolar planets: The Mariotti space interferometer

Icarus ◽

10.1016/j.icarus.2005.05.012 ◽

2005 ◽

Vol 178 (2) ◽

pp. 570-588 ◽

Cited By ~ 26

Author(s):

Bertrand Mennesson ◽

Alain Léger ◽

Marc Ollivier

Keyword(s):

Extrasolar Planets ◽

Direct Detection ◽

Space Interferometer

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Detecting and Characterizing Exoplanets with Direct Imaging: Past, Present, and Future

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313007667 ◽

2013 ◽

Vol 8 (S299) ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Beth Biller

Keyword(s):

Extrasolar Planets ◽

Direct Detection ◽

High Mass ◽

High Contrast ◽

Future Prospects ◽

Contrast Imaging ◽

Direct Imaging ◽

Planet Detection ◽

High Contrast Imaging ◽

Imaging And Spectroscopy

AbstractThe last decade has yielded the first images of exoplanets, considerably advancing our understanding of the properties of young giant planets. In this talk I will discuss current results from ongoing direct imaging efforts as well as future prospects for detection and characterization of exoplanets via high contrast imaging. Direct detection, and direct spectroscopy in particular, have great potential for advancing our understanding of extrasolar planets. In combination with other methods of planet detection, direct imaging and spectroscopy will allow us to eventually: 1) study the physical properties of exoplanets (colors, temperatures, etc.) in depth and 2) fully map out the architecture of typical planetary systems. Direct imaging has offered us the first glimpse into the atmospheric properties of young high-mass (3-10 MJup) exoplanets. Deep direct imaging surveys for exoplanets have also yielded the strongest constraints to date on the statistical properties of wide giant exoplanets. A number of extremely high contrast exoplanet imaging instruments have recently come online or will come online within the next year (including Project 1640, SCExAO, SPHERE, GPI, among others). I will discuss future prospects with these instruments.

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Phase-differential NIR integral field spectroscopy of transiting Hot Jupiters

Proceedings of the International Astronomical Union ◽

10.1017/s174392130802718x ◽

2008 ◽

Vol 4 (S253) ◽

pp. 552-555

Author(s):

Daniel Angerhausen ◽

Alfred Krabbe ◽

Christof Iserlohe

Keyword(s):

Adaptive Optics ◽

Near Infrared ◽

Extrasolar Planets ◽

Atmospheric Composition ◽

Spectroscopic Techniques ◽

Hot Jupiters ◽

Integral Field Spectroscopy ◽

Field Spectroscopy ◽

Advanced Reduction ◽

Integral Field

AbstractTransiting exoplanets provide a unique opportunity for follow up exploration through phase-differential observation of their emission and transmission spectra. From such spectra immediate clues about the atmospheric composition and the planets chemistry can be drawn. Such information is of imminent importance for the theory of the formation of planets in general as well as for their particular evolution. Ground-based spectroscopy of exoplanet transits is a needful extension of results already obtained through space-based observations. We present results of an exploratory study to use near-infrared integral field spectroscopy to observe extrasolar planets. We demonstrate how adaptive optics-assisted integral field spectroscopy compares with other spectroscopic techniques currently applied. An advanced reduction method using elements of a spectral-differential decorrelation method is also discussed. We have tested our concept with a K-Band time series observations of HD209458b and HD189733b obtained with SINFONI at the VLT and OSIRIS at Keck during secondary transits at a spectral resolution of R=3000.

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Optimization and Performance of Adaptive Optics for Imaging Extrasolar Planets

The Astrophysical Journal ◽

10.1086/309777 ◽

1995 ◽

Vol 454 (2) ◽

Cited By ~ 32

Author(s):

Steven M. Stahl ◽

David G. Sandler

Keyword(s):

Adaptive Optics ◽

Extrasolar Planets ◽

And Performance ◽

Optimization And Performance

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Direct detection of hot extrasolar planets with the VLTI using differential interferometry

10.1117/12.390233 ◽

2000 ◽

Cited By ~ 5

Author(s):

Bruno Lopez ◽

Romain G. Petrov ◽

Martin Vannier

Keyword(s):

Extrasolar Planets ◽

Direct Detection ◽

Differential Interferometry

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RefPlanets: Search for reflected light from extrasolar planets with SPHERE/ZIMPOL

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936641 ◽

2020 ◽

Vol 634 ◽

pp. A69 ◽

Cited By ~ 1

Author(s):

S. Hunziker ◽

H. M. Schmid ◽

D. Mouillet ◽

J. Milli ◽

A. Zurlo ◽

...

Keyword(s):

Extrasolar Planets ◽

Direct Detection ◽

Speckle Noise ◽

Detection Methods ◽

Integration Time ◽

Light Sources ◽

Post Processing ◽

Photon Noise ◽

Reflected Light ◽

Blind Search

Aims. RefPlanets is a guaranteed time observation programme that uses the Zurich IMaging POLarimeter (ZIMPOL) of Spectro-Polarimetric High-contrast Exoplanet REsearch instrument at the Very Large Telescope to perform a blind search for exoplanets in wavelengths from 600 to 900 nm. The goals of this study are the characterisation of the unprecedented high polarimetic contrast and polarimetric precision capabilities of ZIMPOL for bright targets, the search for polarised reflected light around some of the closest bright stars to the Sun, and potentially the direct detection of an evolved cold exoplanet for the first time. Methods. For our observations of α Cen A and B, Sirius A, Altair, ɛ Eri and τ Ceti we used the polarimetricdifferential imaging (PDI) mode of ZIMPOL which removes the speckle noise down to the photon noise limit for angular separations ≿0.6′′. We describe some of the instrumental effects that dominate the noise for smaller separations and explain how to remove these additional noise effects in post-processing. We then combine PDI with angular differential imaging as a final layer of post-processing to further improve the contrast limits of our data at these separations. Results. For good observing conditions we achieve polarimetric contrast limits of 15.0–16.3 mag at the effective inner working angle of ~0.13′′, 16.3–18.3 mag at 0.5′′, and 18.8–20.4 mag at 1.5′′. The contrast limits closer in (≾0.6′′) display a significant dependence on observing conditions, while in the photon-noise-dominated regime (≿0.6′′) the limits mainly depend on the brightness of the star and the total integration time. We compare our results with contrast limits from other surveys and review the exoplanet detection limits obtained with different detection methods. For all our targets we achieve unprecedented contrast limits. Despite the high polarimetric contrasts we are not able to find any additional companions or extended polarised light sources in the data obtained so far.

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