Imaging Spectroscopy for Extrasolar Planet Detection

By W. Sparks, H. C. Ford. 2002

290 citations recorded by the source corpus.

We propose that coronagraphic imaging in combination with moderate to high spectral resolution from the outset may prove more effective in both detecting extrasolar planets and characterizing them than a standard coronagraphic imaging approach. We envisage an integral-field spectrograph coupled to a coronagraph to produce a data cube of two space dimensions and one wavelength. For the idealized case where the spectrum of the star is well known and unchanging across the field, we discuss the utility of cross-correlation to seek the extrasolar planet signal and describe a mathematical approach to completely eliminate stray light from the host star (although not its Poisson noise). For the case where the point-spread function (PSF) is dominated by diffraction and scattering effects and comprises a multitude of speckles within an Airy pattern, typical of a space-based observation, we turn the wavelength dependence of the PSF to advantage and present a general way to eliminate the contribution from the star while preserving both the flux and spectrum of the extrasolar planet. We call this method "spectral deconvolution." We illustrate the dramatic gains by showing an idealized simulation that results in a 20 σ detection of a Jovian planet at 2 pc with a 2 m coronagraphic space telescope, even though the planet's peak flux is only 1% that of the PSF wings of the host star. This scales to detection of a terrestrial extrasolar planet at 2 pc with an 8 m coronagraphic Terrestrial Planet Finder in ~7 hr (or less with appropriate spatial filtering). Data on the spectral characteristics of the extrasolar planet and hence on its atmospheric constituents and possible biomarkers are naturally obtained as part of this process.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9c52c6b146791c73611375b66a284dbb629bc847

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Citations in the corpus

Combining high-dispersion spectroscopy with high contrast imaging : Probing rocky planets around our nearest neighbors (2015, methodology): “The technique introduced by Sparks & Ford (2002) has recently been implemented by Konopacky et al. (2013), who have detected carbon monoxide and water in the spectrum of the directly imaged exoplanet HR8799c.”
SPHERE: the exoplanet imager for the Very Large Telescope (2019, background): “High-spectral resolution techniques have long been thought as a means of boosting the sensitivity in direct imaging (Sparks & Ford 2002; Riaud & Schneider 2007) with the capacity of disentangling the stellar and planetary signals thanks to resolved spectral lines.”
The Gemini Deep Planet Survey (2007, methodology): “…it using current instrumentation, can be found in Lafrenière et al. (2007); Hinkley et al. (2007); Marois et al. (2006, 2005); Masciadri et al. (2005); Biller et al. (2004); Schneider & Silverstone (2003); Marois et al. (2003); Sparks & Ford (2002); Marois et al. (2000); Racine et al. (1999).”
Angular Differential Imaging: A Powerful High-Contrast Imaging Technique (2005, background): “…instrument (Marois et al. 2000, 2004, 2005; Doyon et al. 2004; Lafrenière et al. 2004; Biller et al. 2004) or an Integral Field Unit (IFU; Sparks & Ford 2002) to acquire simultaneous images at multiple wavelengths across the methane absorption band head at 1.6 m through the simultaneous…”
Atmospheric characterization of Proxima b by coupling the Sphere high-contrast imager to the Espresso spectrograph (2016, methodology): “It was first envisaged by Sparks & Ford (2002) and Riaud & Schneider (2007), and simulated in details by Snellen et al. (2015).”
A New High Contrast Imaging Program at Palomar Observatory (2010, methodology): “This method, sometimes referred to as spectral deconvolution, has been described before: e.g., Sparks & Ford (2002) and Lafrenière et al. (2007b).”
Adaptive Optics for Astronomy (2012, background): “SD (Sparks & Ford 2002) makes use of the fact that the radial location of the speckles from the centre of the PSF is proportional to wavelength, while the location of a companion with respect to the star is fixed.”
The Structure of High Strehl Ratio Point-Spread Functions (2003, background): “A knowledge of expected speckle symmetries can be combined with the spectral approach of Sparks & Ford (2002) to improve the dynamic range limits derived in that work.”
NEAR-INFRARED SPECTROSCOPY OF THE EXTRASOLAR PLANET HR 8799 b (2010, methodology): “One version of the spectral differential imaging technique (SDI; Sparks & Ford 2002; Thatte et al. 2007) takes advantage of the wavelengthdependent nature of speckle positions to distinguish speckles from bona fide objects, which remain stationary across all wavelengths.5 In principle, integral fiel”
Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report (2015, background): “Speckles can be partially subtracted if certain diversity properties of the data are exploited — in practice either FoV rotation (angular differential imaging) or spectral differencing (Marois et al. 2006, Sparks & Ford 2002).”
CLOUDS AND CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HR8799b (2011, background): “Hence speckle noise patterns will be correlated across the spectrum over a range of 0.05 µm (Sparks & Ford 2002).”
DETECTION AND CHARACTERIZATION OF EXOPLANETS AND DISKS USING PROJECTIONS ON KARHUNEN–LOÈVE EIGENIMAGES (2012, methodology): “…procedures, e.g. Angular Differential Imaging (ADI) (Marois et al. 2006), simultaneous imaging of contiguous wavelengths (Marois et al. 2000; Sparks & Ford 2002; Pueyo et al. 2012), in conjunction with sophisticated images analysis routines based on the Locally Optimized Combination of…”
Apodized Pupil Lyot Coronagraphs for Arbitrary Telescope Apertures (2004, methodology): “The starlight leakage through a coronagraph consists of residual speckles (Sivaramakrishnan et al. 2001), and techniques for their reduction and calibration needs to be developed (Sparks & Ford 2002; Marois et al. 2004; Guyon 2004).”