Selective Principal Component Extraction and Reconstruction: A Novel Method for Ground Based Exoplanet Spectroscopy

Abstract

Context: Infrared spectroscopy of primary and secondary eclipse events probes the composition of exoplanet atmospheres and, using space telescopes, has detected H2O, CH4 and CO2 in three hot Jupiters. However, the available data from space telescopes has limited spectral resolution and does not cover the 2.4 - 5.2 micron spectral region. While large ground based telescopes have the potential to obtain molecular-abundance-grade spectra for many exoplanets, realizing this potential requires retrieving the astrophysical signal in the presence of large Earth-atmospheric and instrument systematic errors. Aims: Here we report a wavelet-assisted, selective principal component extraction method for ground based retrieval of the dayside spectrum of HD 189733b from data containing systematic errors. Methods: The method uses singular value decomposition and extracts those critical points of the Rayleigh quotient which correspond to the planet induced signal. The method does not require prior knowledge of the planet spectrum or the physical mechanisms causing systematic errors. Results: The spectrum obtained with our method is in excellent agreement with space based measurements made with HST and Spitzer (Swain et al. 2009b; Charbonneau et al. 2008) and confirms the recent ground based measurements (Swain et al. 2010) including the strong 3.3 micron emission.

4 pages, 3 figures; excepted for publication by A&A

References in corpus (3)

• The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b
• Strong Water Absorption in the Dayside Emission Spectrum of the Planet HD 189733b
• The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733

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• Optimal Estimation Retrievals of the Atmospheric Structure and Composition of HD 189733b from Secondary Eclipse Spectroscopy
• The Transiting Exoplanet Community Early Release Science Program for JWST
• Ground-based NIR emission spectroscopy of HD189733b
• Of `Cocktail Parties' and Exoplanets
• Blind extraction of an exoplanetary spectrum through Independent Component Analysis
• On signals faint and sparse: the ACICA algorithm for blind de-trending of Exoplanetary transits with low signal-to-noise
• The ground-based H, K, and L-band absolute emission spectra of HD 209458b
• Detrending Exoplanetary Transit Light Curves with Long Short-Term Memory Networks
• A blind method to detrend instrumental systematics in exoplanetary light-curves
• Principal Component Analysis to correct data systematics. Case study: K2 light curves
• Minimal Data Fidelity for Detection of Stellar Features or Companions