Sub-m s${}^{-1}$ upper limits from a deep HARPS-N radial-velocity search for planets orbiting HD 166620 and HD 144579

Abstract

Minimising the impact of stellar variability in Radial Velocity (RV) measurements is a critical challenge in achieving the 10 cm s${}^{-1}$ precision needed to hunt for Earth twins. Since 2012, a dedicated programme has been underway with HARPS-N, to conduct a blind RV Rocky Planets Search (RPS) around bright stars in the Northern Hemisphere. Here we describe the results of a comprehensive search for planetary systems in two RPS targets, HD 166620 and HD 144579. Using wavelength-domain line-profile decorrelation vectors to mitigate the stellar activity and performing a deep search for planetary reflex motions using a trans-dimensional nested sampler, we found no significant planetary signals in the data sets of either of the stars. We validated the results via data-splitting and injection recovery tests. Additionally, we obtained the 95th percentile detection limits on the HARPS-N RVs. We found that the likelihood of finding a low-mass planet increases noticeably across a wide period range when the inherent stellar variability is corrected for using scalpels U-vectors. We are able to detect planet signals with $M\sin i\le 1$ M${}_{\oplus }$ for orbital periods shorter than 10 days. We demonstrate that with our decorrelation technique, we are able to detect signals as low as 54 cm s${}^{-1}$, which brings us closer to the calibration limit of 50 cm s${}^{-1}$ demonstrated by HARPS-N. Therefore, we show that we can push down towards the RV precision required to find Earth analogues using high-precision radial velocity data with novel data-analysis techniques.

arXiv comment7 tables, 24 figures (including those in appendix)

References in corpus (45)

• The SIMBAD astronomical database
• Bayes in the sky: Bayesian inference and model selection in cosmology
• Importance Nested Sampling and the MultiNest Algorithm
• Elemental Abundance Survey of The Galactic Thick Disk
• Towards Better Age Estimates for Stellar Populations: The Y^2 Isochrones for Solar Mixture
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• Chromospheric Activity and Jitter Measurements for 2630 Stars on the California Planet Search
• A Gaussian process framework for modelling stellar activity signals in radial velocity data
• Parametrizing the exoplanet eccentricity distribution with the Beta distribution
• A simple method to estimate radial velocity variations due to stellar activity using photometry
• Using the Sun to estimate Earth-like planets detection capabilities II. Impact of plages
• Planetary detection limits taking into account stellar noise. I. Observational strategies to reduce stellar oscillation and granulation effects
• Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs
• Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs
• Gaia Early Data Release 3: Summary of the contents and survey properties
• On the Mass of CoRoT-7b
• The HARPS-N Rocky Planet Search I. HD219134b: A transiting rocky planet in a multi-planet system at 6.5 pc from the Sun
• Do We Know of Any Maunder Minimum Stars?
• Amplitudes of Stellar Oscillations: The Implications for Asteroseismology
• Three Years of HARPS-N High-Resolution Spectroscopy and Precise Radial Velocity Data for the Sun
• New and updated stellar parameters for 90 transit hosts. The effect of the surface gravity
• An Investigation into the Radial Velocity Variations of CoRoT-7
• Correcting the spectroscopic surface gravity using transits and asteroseismology. No significant effect on temperatures or metallicities with ARES+MOOG in LTE
• pyaneti II: A multidimensional Gaussian process approach to analysing spectroscopic time-series
• Separating planetary reflex Doppler shifts from stellar variability in the wavelength domain
• Filtering solar-like oscillations for exoplanet detection in radial velocity observations
• ARES+MOOG - a practical overview of an EW method to derive stellar parameters
• YARARA: Significant improvement of RV precision through post-processing of spectral time-series
• One year of AU Mic with HARPS: II -- stellar activity and star-planet interaction
• kima: Exoplanet detection in radial velocities
• Radial-velocity discovery of a second planet in the TOI-1338/BEBOP-1 circumbinary system
• The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
• An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561
• A pair of Sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS
• Five Decades of Chromospheric Activity in 59 Sun-like Stars and New Maunder Minimum Candidate HD 166620
• Efficient modeling of correlated noise II. A flexible noise model with fast and scalable methods
• K2-111: an old system with two planets in near-resonance
• Decoding the radial velocity variations of HD41248 with ESPRESSO
• Stellar activity correction using PCA decomposition of shells
• Improving exoplanet detection capabilities with the false inclusion probability. Comparison with other detection criteria in the context of radial velocities
• Atmospheric Stellar Parameters from Cross-Correlation Functions
• Testing whether a signal is strictly periodic. Application to disentangling planets and stellar activity in radial velocities
• The Detection of Earth-mass Planets around Active Stars: The Mass of Kepler-78b
• An Apodized Kepler Periodogram for Separating Planetary and Stellar Activity Signals
• The need for a public forecast of stellar activity to optimise exoplanet radial velocity detections & transmission spectroscopy

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• Chromaticity of stellar activity in radial velocities : Anti-correlated families of lines on the M dwarf EV Lac with SPIRou and SOPHIE
• Using Doppler Imaging to model stellar activity and search for planets around Sun-like stars
• TESS and HARPS-N unveil two planets transiting TOI-1453. A super-Earth and one of the lowest mass sub-Neptunes
• Confronting compositional confusion through the characterisation of the sub-Neptune orbiting HD 77946
• Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903
• Time-resolved p-mode oscillations for subgiant HD 142091 with NEID at WIYN
• Discovery of a multi-planetary system orbiting the aged Sun-like star HD 224018
• Improving exoplanet mass characterisation with Bayesian model selection using the Learned Harmonic Mean Estimator
• Granulation on a quiet K dwarf: HD 166620 I. Spectral signatures as a function of line-formation temperature
• Inferring planet occurrence rates from radial velocities