HD 4915: A Maunder Minimum Candidate

Shivani P. Shah, Jason T. Wright, Howard Isaacson, Andrew W. Howard, Jason L. Curtis

Research output: Contribution to journalArticle

Abstract

We study the magnetic activity cycle of HD 4915 using the Ca ii HK emission line strengths measured by Keck I/High Resolution Echelle Spectrometer (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 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 HK emission lines, and ground- or space-based photometric observations to estimate the sunspot coverage.

Original languageEnglish (US)
Article numberL26
JournalAstrophysical Journal Letters
Volume863
Issue number2
DOIs
StatePublished - Aug 20 2018

Fingerprint

Maunder Minimum
sunspot
stars
sun
spectrometer
planet
magnetic field
chromosphere
monitoring
sunspots
entry
spectrographs
planets
spectrometers
high resolution
estimates
magnetic fields
programme

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Shah, S. P., Wright, J. T., Isaacson, H., Howard, A. W., & Curtis, J. L. (2018). HD 4915: A Maunder Minimum Candidate. Astrophysical Journal Letters, 863(2), [L26]. https://doi.org/10.3847/2041-8213/aad40c
Shah, Shivani P. ; Wright, Jason T. ; Isaacson, Howard ; Howard, Andrew W. ; Curtis, Jason L. / HD 4915 : A Maunder Minimum Candidate. In: Astrophysical Journal Letters. 2018 ; Vol. 863, No. 2.
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Shah, SP, Wright, JT, Isaacson, H, Howard, AW & Curtis, JL 2018, 'HD 4915: A Maunder Minimum Candidate', Astrophysical Journal Letters, vol. 863, no. 2, L26. https://doi.org/10.3847/2041-8213/aad40c

HD 4915 : A Maunder Minimum Candidate. / Shah, Shivani P.; Wright, Jason T.; Isaacson, Howard; Howard, Andrew W.; Curtis, Jason L.

In: Astrophysical Journal Letters, Vol. 863, No. 2, L26, 20.08.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - HD 4915

T2 - A Maunder Minimum Candidate

AU - Shah, Shivani P.

AU - Wright, Jason T.

AU - Isaacson, Howard

AU - Howard, Andrew W.

AU - Curtis, Jason L.

PY - 2018/8/20

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AB - We study the magnetic activity cycle of HD 4915 using the Ca ii HK emission line strengths measured by Keck I/High Resolution Echelle Spectrometer (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 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 HK emission lines, and ground- or space-based photometric observations to estimate the sunspot coverage.

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