The variable magnetic field of V889 Her and the challenge of detecting exoplanets around young Suns using Gaussian process regression
Article
Article Title | The variable magnetic field of V889 Her and the challenge of detecting exoplanets around young Suns using Gaussian process regression |
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Article Category | Article |
Authors | Brown, E. L., Marsden, S. C., Jeffers, S. V., Heitzmann, A., Barnes, J. R. and Folsom, C. P. |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 528 (3) |
Number of Pages | 23 |
Year | 2024 |
Place of Publication | United Kingdom |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/stae264 |
Web Address (URL) | https://academic.oup.com/mnras/article/528/3/4092/7588870 |
Abstract | Discovering exoplanets orbiting young Suns can provide insight into the formation and early evolution of our own solar system, but the extreme magnetic activity of young stars obfuscates exoplanet detection. Here we monitor the long-term magnetic field and chromospheric activity variability of the young solar analogue V889 Her, model the activity-induced radial velocity variations, and evaluate the impacts of extreme magnetism on exoplanet detection thresholds. We map the magnetic field and surface brightness for 14 epochs between 2004 and 2019. Our results show potential 3–4 yr variations of the magnetic field that evolves from weak and simple during chromospheric activity minima to strong and complex during activity maxima but without any polarity reversals. A persistent, temporally varying polar spot coexists with weaker, short-lived lower-latitude spots. Due to their different decay time-scales, significant differential rotation, and the limited temporal coverage of our legacy data, we were unable to reliably model the activity-induced radial velocity using Gaussian Process regression. Doppler Imaging can be a useful method for modelling the magnetic activity jitter of extremely active stars using data with large phase gaps. Given our data and using Doppler Imaging to filter activity jitter, we estimate that we could detect Jupiter-mass planets with orbital periods of ∼3 d. A longer baseline of continuous observations is the best observing strategy for the detection of exoplanets orbiting highly active stars. |
Keywords | planets and satellites: detection; stars: magnetic field; stars: individual: V889 Her |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Byline Affiliations | Centre for Astrophysics |
Central Queensland University | |
Max Planck Institute for Solar System Research, Germany | |
University of Geneva, Switzerland | |
Open University, United Kingdom | |
University of Tartu, Estonia |
https://research.usq.edu.au/item/z5qqv/the-variable-magnetic-field-of-v889-her-and-the-challenge-of-detecting-exoplanets-around-young-suns-using-gaussian-process-regression
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