Insights on the Spectral Signatures of Stellar Activity and Planets from PCA

Abstract

Photospheric velocities and stellar activity features such as spots and faculae produce measurable radial velocity signals that currently obscure the detection of sub-meter-per-second planetary signals. However, photospheric velocities are imprinted differently in a high-resolution spectrum than Keplerian Doppler shifts. Photospheric activity produces subtle differences in the shapes of absorption lines due to differences in how temperature or pressure affects the atomic transitions. In contrast, Keplerian Doppler shifts affect every spectral line in the same way. With high enough S/N and high enough resolution, statistical techniques can exploit differences in spectra to disentangle the photospheric velocities and detect lower-amplitude exoplanet signals. We use simulated disk-integrated time-series spectra and principal component analysis (PCA) to show that photospheric signals introduce spectral line variability that is distinct from Doppler shifts. We quantify the impact of instrumental resolution and S/N for this work.

12 pages, 7 figures, accepted to ApJ

References in corpus (11)

• Three regimes of extrasolar planets inferred from host star metallicities
• SOAP 2.0: A tool to estimate the photometric and radial velocity variations induced by stellar spots and plages
• TW Hydrae: evidence of stellar spots instead of a Hot Jupiter
• Instrumentation for the detection and characterization of exoplanets
• Radial-Velocity Fitting Challenge. II. First results of the analysis of the data set
• A comprehensive radial velocity error budget for next generation Doppler spectrometers
• Variability of stellar granulation and convective blueshift with spectral type and magnetic activity. I. K and G main sequence stars
• The Changing Face of $\alpha$ Centauri B: Probing plage and stellar activity in K-dwarfs
• Variations of the solar granulation motions with height using the GOLF/SoHO experiment
• A combined spectroscopic and photometric stellar activity study of Epsilon Eridani
• Magnetic field measurements of $\epsilon$ Eridani from Zeeman broadening

Cited by in corpus (37)

• Measuring precise radial velocities on individual spectral lines : II. Dependance of stellar activity signal on line depth
• Separating planetary reflex Doppler shifts from stellar variability in the wavelength domain
• YARARA: Significant improvement of RV precision through post-processing of spectral time-series
• Performance Verification of the EXtreme PREcision Spectrograph
• How magnetic activity alters what we learn from stellar spectra
• The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
• Toward Extremely Precise Radial Velocities: II. A Tool For Using Multivariate Gaussian Processes to Model Stellar Activity
• Statistical methods for exoplanet detection with radial velocities
• Stellar activity correction using PCA decomposition of shells
• Target Prioritization and Observing Strategies for the NEID Earth Twin Survey
• A robust, template-free approach to precise radial velocity extraction
• Modeling the Echelle Spectra Continuum with Alpha Shapes and Local Regression Fitting
• Impact of Correlated Noise on the Mass Precision of Earth-analog Planets in Radial Velocity Surveys
• SOAP-GPU: Efficient Spectral Modelling of Stellar Activity Using Graphical Processing Units
• The Chemical Nature of the Young 120-Myr-old Nearby Pisces-Eridanus Stellar Stream Flowing through the Galactic Disk
• Optical and near-infrared stellar activity characterization of the early M dwarf Gl~205 with SOPHIE and SPIRou
• Mitigating stellar activity jitter with different line lists for least-squares deconvolution: analysis of a parametric and a randomised line selection
• EXPRES. III. Revealing the Stellar Activity Radial Velocity Signature of $\epsilon$ Eridani with Photometry and Interferometry
• Rotational modulation of spectroscopic Zeeman signatures in low-mass stars
• Final Design and On-Sky Testing of the iLocater SX Acquisition Camera: Broadband Single-Mode Fiber Coupling
• Activity and telluric contamination in HARPS observations of Alpha Centauri B
• Improving Earth-like planet detection in radial velocity using deep learning
• EXPRES. II. Searching for Planets Around Active Stars: A Case Study of HD 101501
• Characterization of Single-Mode Fiber Coupling at the Large Binocular Telescope
• TOI-1055 b: Neptunian planet characterised with HARPS, TESS, and CHEOPS
• The Measured Impact of Chromatic Atmospheric Effects on Barycentric Corrections: Results from the EXtreme PREcision Spectrograph
• The CARMENES search for exoplanets around M dwarfs. Line-by-line sensitivity to activity in M dwarfs
• Accounting for stellar activity signals in radial-velocity data by using Change Point Detection techniques
• Identifying Exoplanets with Deep Learning. IV. Removing Stellar Activity Signals from Radial Velocity Measurements Using Neural Networks
• Solar photospheric spectrum microvariability II. Observed relations to magnetic activity and radial-velocity modulation
• A Stellar Activity F-statistic for Exoplanet Surveys (SAFE)
• Data Reduction Pipeline of the TOU Optical Very High Resolution Spectrograph and Its sub-m/s Performance
• Semi-supervised standardized detection of extrasolar planets
• A Hermite-Gaussian Based Radial Velocity Estimation Method
• Minimal Data Fidelity for Detection of Stellar Features or Companions
• Ground-Based Radial Velocity as Critical Support for Future NASA Earth-Finding Missions
• Friends and Foes: Conditional Occurrence Rates of Exoplanet Companions and their Impact on Radial Velocity Follow-up Surveys