Magnetic activity variability from H$\alpha$ line intensive monitoring for two F-type stars having a hot-Jupiter, $\tau$ Bootis A and $\upsilon$ Andromedae A

Abstract

We report the results of intensive monitoring of the variability in the H$\alpha$ line for two F-type stars, $\tau$ Boo and $\upsilon$ And, during the last four years 2019-2022, in order to investigate their stellar magnetic activity. The 4-year H$\alpha$ line intensity data taken with the 1.88-m reflector at Okayama Branch Office, Subaru Telescope, shows the existence of a possible $\sim$ 123-day magnetic activity cycle of $\tau$ Boo. The result of the H$\alpha$ variability as another tracer of the magnetic activity on the chromosphere is consistent with previous studies of the Ca II H&K line and suggests that the magnetic activity cycle is persisted in $\tau$ Boo. For $\upsilon$ And, we suggest a quadratic long-term trend in the H$\alpha$ variability. Meanwhile, the short-term monitoring shows no significant period corresponding to specific variations likely induced by their hot-Jupiter in both cases ($\approx$ 3.31 and 4.62 days, respectively). In this H$\alpha$ observation, we could not find any signature of the Star-Planet Magnetic Interaction. It is speculated that the detected magnetic activity variability of the two F-type stars is related to the stellar intrinsic dynamo.

27 pages, 20 figures, 1 table, Accepted by Publications of the Astronomical Society of Japan

References in corpus (8)

• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• The On/Off Nature of Star-Planet Interactions
• Magnetic field strengths of hot Jupiters from signals of star-planet interactions
• Discovery of a 1.6-year Magnetic Activity Cycle in the Exoplanet Host Star iota Horologii
• The search for radio emission from the exoplanetary systems 55 Cancri, $\upsilon$ Andromedae, and $\tau$ Boötis using LOFAR beam-formed observations
• Tracers of Chromospheric Structure I: Observations of Ca II K and H alpha in M Dwarfs
• The GAPS Programme with HARPS-N at TNG. VII. Putting exoplanets in the stellar context: magnetic activity and asteroseismology of $\tau$ Bootis A
• Detection of Water Vapor in the Thermal Spectrum of the Non-Transiting Hot Jupiter upsilon Andromedae b

Cited by in corpus (1)

• Doppler imaging combined with high-cadence photometry. I. Revisiting the surface of a pre-main-sequence flare star