Wednesday 17 Feb 2021: The past and future of the Sun: What solar twins can tell us about the solar dynamo evolution?
Diego Lorenzo-Oliveira -
Remote seminar 14:00-15:00
Rotation-based ages of old Sun-like stars are rooted in a complex and intricate dependence on age, rotation, turbulent convection, structural variations, and mass-loss due to magnetized winds. Classically, the age-dating method that relies on this phenomenon assumes that the rotational periods can be expressed in well-defined functions of the age and mass, the so-called gyrochronology relations. These relations had successfully confirmed the paradigm of rotation-activity-age coupling that powers the global dynamo evolution along the main-sequence and reproduced the main features observed in open clusters spanning a wide range of ages. However, in the light of Kepler data, the presence of apparently old and fast rotators that do not obey the usual gyrochronology relations led to the hypothesis of weakened magnetic breaking in some solar-type stars. In the first part of this talk, I will address this issue using a large sample of nearby solar-twins where activity levels and long rotation periods are found for the oldest and most inactive main-sequence stars. This result challenges the hypothesis of dynamo disruption in middle-age solar-mass stars.
Finally, I will highlight some of our efforts to pull out the multi-wavelength activity and radial velocity information from ESPRESSO/HARPS high-cadence observations.