HD 4915: A Maunder Minimum Candidate

Abstract

We study the magnetic activity cycle of HD 4915 using the \ion{Ca}{2} H \& K emission line strengths measured by Keck I/HIRES spectrograph. The star has been observed as a part of California Planet Search Program from 2006 to present. We note decreasing amplitude in the magnetic activity cycle, a pattern suggesting the star's entry into a Magnetic Grand Minimum (MGM) state, reminiscent of the Sun's Maunder and Dalton Minima. We recommend further monitoring of the star to confirm the grand minimum nature of the dynamo, which would provide insight into the state of the Sun's chromosphere and the global magnetic field during its grand minima. We also recommend continued observations of H \& K emission lines, and ground or space based photometric observations to estimate the sunspot coverage.

To be submitted to AAS Journals; comments welcome

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Cited by in corpus (8)

• How much has the Sun influenced Northern Hemisphere temperature trends? An ongoing debate
• Models for the long-term variations of solar activity
• Five Decades of Chromospheric Activity in 59 Sun-like Stars and New Maunder Minimum Candidate HD 166620
• Astrophysical Insights into Radial Velocity Jitter from an Analysis of 600 Planet-search Stars
• Dynamo modelling for cycle variability and occurrence of grand minima in Sun-like stars: Rotation rate dependence
• The California-Kepler Survey. XI. A Survey of Chromospheric Activity Through the Lens of Precise Stellar Properties
• Stellar cycle variability in Mount Wilson stars and dynamo models: Rotation rate and dynamo number dependency
• HD 166620: Portrait of a Star Entering a Grand Magnetic Minimum