Sub-m s−1 upper limits from a deep HARPS-N radial-velocity search for planets orbiting HD 166620 and HD 144579
Abstract
Minimizing 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 scalpelsU-vectors. We are able to detect planet signals with Msin i ≤ 1 M⊕ for orbital periods shorter than 10 d. 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.
Citation
Anna John , A , Collier Cameron , A , Faria , J P , Mortier , A , Wilson , T G , Malavolta , L , Buchhave , L A , Dumusque , X , López-Morales , M , Haywood , R D , Rice , K , Sozzetti , A , Latham , D W , Udry , S , Pepe , F , Pinamonti , M , Vanderburg , A , Ghedina , A , Cosentino , R , Stalport , M , Nicholson , B A , Fiorenzano , A & Poretti , E 2023 , ' Sub-m s −1 upper limits from a deep HARPS-N radial-velocity search for planets orbiting HD 166620 and HD 144579 ' , Monthly Notices of the Royal Astronomical Society , vol. 525 , no. 2 , pp. 1687-1704 . https://doi.org/10.1093/mnras/stad2381
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
ISSN
0035-8711Type
Journal article
Description
Funding: JPF acknowledges Fundação para a Ciência a Tecnologia (FCT, Portugal) for the research grants UIDB/04434/2020 and UIDP/04434/2020 and by POCH/FSE (EC) through the grant EXPL/FIS-AST/0615/2021. JPF is supported in the form of a work contract funded by national funds through FCT with reference DL57/2016/CP1364/CT0005. KR is grateful for support from UK Science and Technology Facilities Council (STFC) via consolidated grant ST/V000594/1. RDH is funded by UK STFC’s Ernest Rutherford Fellowship (grant number ST/V004735/1). This project has received funding from European Research Council (ERC) under European Unions' Horizon 2020 research and innovation programme (grant agreement SCORE number 851555).Collections
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