Detection of planetary signals by reflected light of the host star using the autocorrelation of spectra

Abstract

We consider an alternative to the cross-correlation function (CCF), that uses the autocor- relation function (ACF), to measure in spectra the reflected light of the stars by their planetary companion. The objective of this work is to assess and analyse the efficiency of the ACF in detecting planetary signals by a detection of reflected light. To do so, we first compare the ACF and the CCF using artificial spectra containing a planetary signal. We then use the ACF to analyse spectra of the 51 Peg + 51 Peg b system and compare our results with those obtained by Martins et al. (2015) who previously analysed the same system using the CCF. The functionalities of the ACF and the way it is implemented are similar to that of the CCF. One of the main advantages of the ACF is the fact that, unlike the CCF, no weighted binary mask is required. This makes the ACF easier to use. The results related to simulated spectra showed that the ACF allowed us to decrease the boundary condition threshold for the use of spectra compared to the CCF so that more data could be used to recover the planetary signal. For the 51 Peg b planet, we achieved a detection significance of 5.52 σnoise with the ACF compared to 3.70 σnoise with the CCF (Martins et al. 2015). We conclude that the ACF has the potential to become a prominent technique in detecting exoplanets considering its efficiency, ease of use and rapid execution time.

arXiv commentAccepted for publication in MNRAS 20 september 2018

References in corpus (17)

• Detection of Planetary Transits Across a Sun-like Star
• Theoretical Transmission Spectra During Extrasolar Giant Planet Transits
• Least squares deconvolution of the stellar intensity and polarization spectra
• Reflected Spectra and Albedos of Extrasolar Giant Planets I: Clear and Cloudy Atmospheres
• Theoretical Spectra and Atmospheres of Extrasolar Giant Planets
• Detecting Planets Around Very Low Mass Stars with the Radial Velocity Method
• The Very Low Albedo of an Extrasolar Planet: MOST Spacebased Photometry of HD 209458
• An Upper Limit on the Reflected Light from the Planet Orbiting the Star tau Bootis
• Detection of molecular absorption in the dayside of exoplanet 51 Pegasi b?
• Exoplanet albedo spectra and colors as a function of planet phase, separation, and metallicity
• Discovery of water at high spectral resolution in the atmosphere of 51 Peg b
• Analytic models for albedos, phase curves and polarization of reflected light from exoplanets
• Evidence for a spectroscopic direct detection of reflected light from 51 Peg b
• Spectroscopic direct detection of reflected light from extra-solar planets
• Tau Boo b: Hunting for reflected starlight
• Measurements of stellar magnetic fields with the autocorrelation of spectra
• Measurements of microturbulence of Cepheids using the autocorrelation function

Cited by in corpus (8)

• Observability of Forming Planets and their Circumplanetary Disks II. -- SEDs and Near-Infrared Fluxes
• Black Mirror: The impact of rotational broadening on the search for reflected light from 51 Pegasi b with high resolution spectroscopy
• Can close-in giant exoplanets preserve detectable moons?
• Close-in Exoplanets as Candidates of Strange Quark Matter Objects
• The GAPS Programme at TNG. XXIX. No detection of reflected light from 51 Peg b using optical high-resolution spectroscopy
• Prospects for Directly Imaging Young Giant Planets at Optical Wavelengths
• Reflected Light Phase Curves in the TESS Era
• Using Independent Component Analysis to detect exoplanet reflection spectrum from composite spectra of exoplanetary binary systems