273 citations · 1.7k across the 32 of their papers we have counts for
30 papers · 1 filter
Rotational evolution of slow-rotator sequence stars. II. Modeling the wind braking and the rotational coupling in the entire mass range of solar-like stars
F. Spada, A. C. Lanzafame
In recent years, ground- and space-based photometric surveys have characterized the rotational evolution of solar-like stars to an unprecedented level of detail. In this work we fo…
Asteroseismology of evolved stars to constrain the internal transport of angular momentum. VI. Testing a parametric formulation for the azimuthal magneto-rotational instability
F. D. Moyano, P. Eggenberger, B. Mosser +1
Asteroseismic measurements of the internal rotation rate in evolved stars pointed out to a lack of angular momentum (AM) transport in stellar evolution models. Several physical pro…
KIC 7955301: a hierarchical triple system with eclipse timing variations and an oscillating red giant
P. Gaulme, T. Borkovits, T. Appourchaux +13
KIC 7955301 is a hierarchical triple system with eclipse timing and depth variations discovered by the Kepler mission. It is composed of a non-eclipsing primary star at the bottom…
Stellar evolution models with entropy-calibrated mixing-length parameter: application to red giants
Federico Spada, Pierre Demarque, Friedrich Kupka
We present evolutionary models for solar-like stars with an improved treatment of convection that results in a more accurate estimate of the radius and effective temperature. This…
Seismic evidence for near solid-body rotation in two Kepler subgiants and implications for angular momentum transport
S. Deheuvels, J. Ballot, P. Eggenberger +3
Asteroseismic measurements of the internal rotation of subgiants and red giants all show the need for invoking a more efficient transport of angular momentum than theoretically pre…
A Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitions
Jyri J. Lehtinen, Maarit J. Käpylä, Nigul Olspert +1
The magnetic activity of late-type stars is correlated with their rotation rates. Up to a certain limit, stars with smaller Rossby numbers, defined as the rotation period divided b…
Active red giants: close binaries versus single rapid rotators
Patrick Gaulme, Jason Jackiewicz, Federico Spada +7
The objective of this work is to determine what fraction of red-giant (RG) stars shows photometric rotational modulation, and understand its origin. One of the underlying questions…
Common dynamo scaling in slowly rotating young and evolved stars
Jyri J. Lehtinen, Federico Spada, Maarit J. Käpylä +2
One interpretation of the activity and magnetism of late-type stars is that these both intensify with decreasing Rossby number up to a saturation level, suggesting that stellar dyn…
Testing the entropy calibration of the radii of cool stars: models of alpha Centauri A and B
F. Spada, P. Demarque
We present models of alpha Centauri A and B implementing an entropy calibration of the mixing-length parameter alpha_MLT, recently developed and successfully applied to the Sun (Sp…
On the competing effect of wind braking and interior coupling in the rotational evolution of solar-like stars
F. Spada, A. C. Lanzafame
Solar-like stars (M < 1.3 Msun) lose angular momentum through their magnetized winds. The resulting evolution of the surface rotation period, which can be directly measured photome…
Asteroseismology of evolved stars to constrain the internal transport of angular momentum. I. Efficiency of transport during the subgiant phase
P. Eggenberger, S. Deheuvels, A. Miglio +9
Context: The observations of solar-like oscillations in evolved stars have brought important constraints on their internal rotation rates. To correctly reproduce these data, an eff…
Improved calibration of the radii of cool stars based on 3D simulations of convection: implications for the solar model
F. Spada, P. Demarque, S. Basu +1
Main sequence, solar-like stars (M < 1.5 Msun) have outer convective envelopes that are sufficiently thick to affect significantly their overall structure. The radii of these stars…
Solar radius and luminosity variations induced by the internal dynamo magnetic fields
F. Spada, R. Arlt, M. Kueker +1
Although the occurrence of solar irradiance variations induced by magnetic surface features (e.g., sunspots, faculae, magnetic network) is generally accepted, the existence of intr…
Evidence of New Magnetic Transitions in Late-Type Dwarfs from Gaia DR2
Alessandro C. Lanzafame, Elisa Distefano, Sydney A. Barnes +1
The second Gaia data release contains the identification of 147 535 low-mass () rotational modulation variable candidates on (or close to) the main sequence, tog…
Activity cycles in members of young loose stellar associations
E. Distefano, A. C. Lanzafame, A. Lanza +2
Magnetic cycles have been detected in tens of solar-like stars. The relationship between the cycle properties and global stellar parameters is not fully understood yet. We searched…
Lithium abundance and 6Li/7Li ratio in the active giant HD123351 I. A comparative analysis of 3D and 1D NLTE line-profile fits
A. Mott, M. Steffen, E. Caffau +2
Current three-dimensional (3D) hydrodynamical model atmospheres together with NLTE spectrum synthesis, permit to derive reliable atomic and isotopic chemical abundances from high-r…
The Sirius System and its Astrophysical Puzzles: Hubble Space Telescope and Ground-Based Astrometry
Howard E. Bond, Gail H. Schaefer, Ronald L. Gilliland +11
Sirius, the seventh-nearest stellar system, is a visual binary containing the metallic-line A1 V star Sirius A, brightest star in the sky, orbited in a 50.13-year period by Sirius…
The Yale-Potsdam Stellar Isochrones (YaPSI)
F. Spada, P. Demarque, Y. -C. Kim +2
We introduce the Yale-Potsdam Stellar Isochrones (YaPSI), a new grid of stellar evolution tracks and isochrones of solar-scaled composition. In an effort to improve the Yonsei-Yale…
Evidence of radius inflation in stars approaching the slow-rotator sequence
Alessandro C. Lanzafame, Federico Spada, Elisa Distefano
Average stellar radii in open clusters can be estimated from rotation periods and projected rotational velocities under the assumption of random orientation of the spin axis. Such…
Sunspot positions, areas, and group tilt angles for 1611-1631 from observations by Christoph Scheiner
R. Arlt, V. Senthamizh Pavai, C. Schmiel +1
Digital images of the observations printed in the books "Rosa Ursina sive solis" and "Prodromus pro sole mobili" by Christoph Scheiner as well as the drawings from Scheiner's lette…
Lower limit for differential rotation in members of young loose stellar associations
E. Distefano, A. C. Lanzafame, A. F. Lanza +2
Surface differential rotation (SDR) plays a key role in dynamo models. SDR estimates are therefore essential for constraining theoretical models. We measure a lower limit to SDR in…
Angular momentum transport efficiency in post-main sequence low-mass stars
F. Spada, M. Gellert, R. Arlt +1
Context. Using asteroseismic techniques, it has recently become possible to probe the internal rotation profile of low-mass (~1.1-1.5 Msun) subgiant and red giant stars. Under the…
A color-period diagram for the open cluster M 48 (NGC 2548), and its rotational age
Sydney A. Barnes, Jörg Weingrill, Thomas Granzer +2
Rotation periods are increasingly being used to derive ages for cool single field stars. Such ages are based on an empirical understanding of how cool stars spin down, acquired by…
Rotational evolution of slow-rotators sequence stars
Alessandro C. Lanzafame, Federico Spada
The observed mass-age-rotation relationship in open clusters shows the progressive development of a slow-rotators sequence. The observed clustering on this sequence suggests that i…