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Unsigned magnetic flux as a proxy for radial-velocity variations in sun-like stars

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العنوان: Unsigned magnetic flux as a proxy for radial-velocity variations in sun-like stars
المؤلفون: Haywood, R. D., Milbourne, T. W., Saar, S. H., Mortier, A., Phillips, D., Charbonneau, D., Cameron, A. Collier, Cegla, H. M., Meunier, N., III, M. L. Palumbo
المساهمون: Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science
سنة النشر: 2022
المجموعة: University of St Andrews: Digital Research Repository
مصطلحات موضوعية: Solar cycle, Active sun, Quiet sun, Sunspots, Solar faculae, Exoplanet detection methods, Radial velocity, Astronomy data analysis, QB Astronomy, QC Physics, 3rd-DAS, QB, QC
الوصف: Funding: A.C.C. acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. ; A major obstacle to detecting and characterizing long-period, low-mass exoplanets is the intrinsic radial-velocity (RV) variability of host stars. To better understand RV variability, we estimate disk-averaged RV variations of the Sun over its magnetic cycle, from the Fe i line observed by SDO/HMI, using a physical model for rotationally modulated magnetic activity that was previously validated against HARPS-N solar observations. We estimate the unsigned magnetic flux and show that a linear fit to it reduces the rms of RV variations by 62%, i.e., a factor of 2.6. We additionally apply the FF′ method, which predicts RV variations based on a star’s photometric variations. At cycle maximum, we find that additional processes must be at play beyond suppression of convective blueshift and velocity imbalances resulting from brightness inhomogeneities, in agreement with recent studies of RV variations. By modeling RV variations over the magnetic cycle using a linear fit to the unsigned magnetic flux, we recover injected planets at a period of ≈300 days with RV semi-amplitudes down to 0.3 m s−1. To reach 0.1 m s−1, we will need to identify and model additional phenomena that are not well traced by ∣Bˆobs∣ or FF′. This study motivates ongoing and future efforts to develop observation and analysis techniques to measure the unsigned magnetic flux at high precision in slowly rotating, relatively inactive stars like the Sun. We conclude that the unsigned magnetic flux is an excellent proxy for rotationally modulated, activity-induced RV variations, and could become key to confirming and characterizing Earth analogs. ; Publisher PDF ; Peer reviewed
نوع الوثيقة: article in journal/newspaper
وصف الملف: application/pdf
اللغة: English
تدمد: 0004-637X
Relation: Astrophysical Journal; Haywood , R D , Milbourne , T W , Saar , S H , Mortier , A , Phillips , D , Charbonneau , D , Cameron , A C , Cegla , H M , Meunier , N & III , M L P 2022 , ' Unsigned magnetic flux as a proxy for radial-velocity variations in sun-like stars ' , Astrophysical Journal , vol. 935 , no. 1 , 6 . https://doi.org/10.3847/1538-4357/ac7c12; PURE: 280849641; PURE UUID: 575ba676-08b4-4739-868a-526d940553ff; Jisc: 513174; publisher-id: apjac7c12; manuscript: ac7c12; other: aas24808; ORCID: /0000-0002-8863-7828/work/117211243; Scopus: 85135988681; WOS: 000837396900001; http://hdl.handle.net/10023/25889; https://doi.org/10.3847/1538-4357/ac7c12; ST/R00824/1
DOI: 10.3847/1538-4357/ac7c12
الاتاحة: http://hdl.handle.net/10023/25889
https://doi.org/10.3847/1538-4357/ac7c12
Rights: Copyright © 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
رقم الانضمام: edsbas.9EE92687
قاعدة البيانات: BASE
الوصف
تدمد:0004637X
DOI:10.3847/1538-4357/ac7c12