Magnetic fields on young, moderately rotating Sun-like stars - I: HD~35296 and HD~29615

Abstract

Observations of the magnetic fields of young solar-type stars provide a way to investigate the signatures of their magnetic activity and dynamos. Spectropolarimetry enables the study of these stellar magnetic fields and was thus employed at the Télescope Bernard Lyot and the Anglo-Australian Telescope to investigate two moderately rotating young Sun-like stars, namely HD 35296 (V119 Tau, HIP 25278) and HD 29615 (HIP 21632). The results indicate that both stars display rotational variation in chromospheric indices consistent with their spot activity, with variations indicating a probable long-term cyclic period for HD 35296. Additionally, both stars have complex, and evolving, large-scale surface magnetic fields with a significant toroidal component. High levels of surface differential rotation were measured for both stars. For the F8V star HD 35296 a rotational shear of $\Delta \Omega$ = 0.22${}_{-0.02}^{+0.04}$ rad/d was derived from the observed magnetic profiles. For the G3V star HD 29615 the magnetic features indicate a rotational shear of $\Delta \Omega$ = 0.48${}_{-0.12}^{+0.11}$ rad/d, while the spot features, with a distinctive polar spot, provide a much lower value of $\Delta \Omega$ of 0.07${}_{-0.03}^{+0.10}$ rad/d. Such a significant discrepancy in shear values between spot and magnetic features for HD 29615 is an extreme example of the variation observed for other lower-mass stars. From the extensive and persistent azimuthal field observed for both targets it is concluded that a distributed dynamo operates in these moderately rotating Sun-like stars, in marked contrast to the Sun's interface-layer dynamo.

arXiv comment18 Pages, 13 figures, 5 tables, accepted for publication in MNRAS

References in corpus (36)

• Validation of the new Hipparcos reduction
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Chromospheric CaII Emission in Nearby F, G, K, and M stars
• The Geneva-Copenhagen Survey of the Solar neighbourhood III. Improved distances, ages, and kinematics
• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• Late-type stars members of young stellar kinematic groups - I. Single stars
• Rotation and differential rotation of active Kepler stars
• Least squares deconvolution of the stellar intensity and polarization spectra
• The Palomar/MSU Nearby Star Spectroscopic Survey III: Chromospheric Activity, M-dwarf Ages and the Local Star Formation History
• Search for Associations Containing Young stars (SACY): I. Sample & Searching Method
• Stellar Limb-Darkening Coefficients for CoRot and Kepler
• Toroidal versus poloidal magnetic fields in Sun-like stars: a rotation threshold
• The Dependence of Differential Rotation on Temperature and Rotation
• Persistent Magnetic Wreaths in a Rapidly Rotating Sun
• A Bcool magnetic snapshot survey of solar-type stars
• Magnetic cycles of the planet-hosting star Tau Bootis: II. a second magnetic polarity reversal
• POLLUX : a database of synthetic stellar spectra
• RACE-OC Project: Rotation and variability in young stellar associations within 100 pc
• Temporal fluctuations in the differential rotation of cool active stars
• Rotation- and temperature-dependence of stellar latitudinal differential rotation
• Lithium abundances for 185 main-sequence stars - Galactic evolution and stellar depletion of lithium
• New measurements of rotation and differential rotation in A-F stars: Are there two populations of differentially rotating stars?
• Differential rotation of main-sequence dwarfs and its dynamo-efficiency
• Long-term magnetic field monitoring of the Sun-like star ξBootis A
• Differential rotation in rapidly rotating F-stars
• Magnetic topology and surface differential rotation on the K1 subgiant of the RS CVn system HR 1099
• Stokes IQUV Magnetic Doppler Imaging of Ap stars I. ESPaDOnS and NARVAL Observations
• Magnetic fields and differential rotation on the pre-main sequence I: The early-G star HD 141943 - brightness and magnetic topologies
• Stellar differential rotation from direct starspot tracking
• The differential rotation of G dwarfs
• Photospheric magnetic field and surface differential rotation of the FK Com star HD 199178
• Magnetic fields and differential rotation on the pre-main sequence II: The early-G star HD 141943 - coronal magnetic field, H-alpha emission and differential rotation
• Magnetic fields and differential rotation on the pre-main sequence III: The early-G star HD 106506
• Differential rotation on both components of the pre main-sequence binary system HD 155555
• How reliable is Zeeman Doppler Imaging without simultaneous temperature reconstruction?
• High Resolution Spectroscopy and Spectropolarimetry of some late F-/early G-type sun-like stars as targets for Zeeman Doppler imaging

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• Magnetic fields on young, moderately rotating Sun-like stars II. EK Draconis (HD 129333)
• Do non-dipolar magnetic fields contribute to spin-down torques?
• Forward modelling of brightness variations in Sun-like stars I. Emergence and surface transport of magnetic flux
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• Linking chromospheric activity and magnetic field properties for late-type dwarf stars
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• The Solar Wind Environment in Time
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• Magnetic field and chromospheric activity evolution of HD75332: a rapid magnetic cycle in an F star without a hot Jupiter
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• A BCool survey of stellar magnetic cycles
• HARPS spectropolarimetry of three sharp-lined Herbig Ae stars: New insights
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• Forward modelling of brightness variations in Sun-like stars -- II. Light curves and variability
• Stellar Coronal and Wind Models: Impact on Exoplanets
• Correlating Intrinsic Stellar Parameters with Mg II Self-Reversal Depths
• The CARMENES search for exoplanets around M dwarfs : Understanding the wavelength dependence of radial velocity measurements
• Far beyond the Sun: III. The magnetic cycle of $\mathbf{\iota }$ Horologii
• Zeeman Doppler Imaging of $\tau$Ceti: The Weakest Magnetic Field Detected in a Sun-like Star