Asteroseismology of solar-type stars

Abstract

Until the last few decades, investigations of stellar interiors had been restricted to theoretical studies only constrained by observations of their global properties and external characteristics. However, in the last 30 years the field has been revolutionized by the ability to perform seismic investigations of stellar interiors. This revolution begun with the Sun, where helioseismology has been yielding information competing with what can be inferred about the Earth’s interior from geoseismology. The last two decades have witnessed the advent of asteroseismology of solar-like stars, thanks to a dramatic development of new observing facilities providing the first reliable results on the interiors of distant stars. The coming years will see a huge development in this field. In this review we focus on solar-type stars, i.e., cool main-sequence stars where oscillations are stochastically excited by surface convection. After a short introduction and a historical overview of the discipline, we review the observational techniques generally used, and we describe the theory behind stellar oscillations in cool main-sequence stars. We continue with a complete description of the normal mode analyses through which it is possible to extract the physical information about the structure and dynamics of the stars. We then summarize the lessons that we have learned and discuss unsolved issues and questions that are still unanswered.

Evidence for ≳4 Gyr timescales of neutron star mergers from Galactic archaeology

“…3 shows [Eu/Mg] with age in solar twins with astroseismic age measurements, which are among the most accurate stellar ages achievable to date (e.g. García & Ballot 2019). There is a clear increase in [Eu/Mg] with age, indicative of a delayed component in the production of Eu.…”

Asteroseismology of High-Mass Stars: New Insights of Stellar Interiors With Space Telescopes

“…This can allow p and g modes to couple with each other and form mixed modes, which are modes with the character of a p mode in the envelope and the character of a g mode in the deep interior (Aerts et al, 2010). The regularities of asymptotic p modes in the amplitude spectra of low-and intermediatemass stars has greatly simplified the issue of mode identification and facilitated asteroseismology for low-mass stars (see e.g., Chaplin and Miglio, 2013;Hekker and Christensen-Dalsgaard, 2017;García and Ballot, 2019), but are rarely observed in massive stars (see e.g., Belkacem et al, 2010;Degroote et al, 2010b). Such high-radial order p modes are generally not expected for massive stars owing to the excitation physics of the κ-mechanism being inefficient in driving such modes in massive stars Gautschy and Saio, 1993;Pamyatnykh, 1999;Miglio et al, 2007).…”

“…Until recently, most observational studies of massive stars have focused on the determination of global and/or average properties of these stars, such as the effective temperature and surface gravity derived from spectroscopy being used to estimate masses and ages. On the other hand, the recent space photometry revolution has truly brought asteroseismology to the forefront of astronomy as a means to calibrate stellar evolution theory across the Hertzsprung-Russell (HR) diagram (Chaplin and Miglio, 2013;Hekker and Christensen-Dalsgaard, 2017;García and Ballot, 2019;Aerts, 2020).…”

The TOI-763 system: sub-Neptunes orbiting a Sun-like star

“…Being larger than twice the Earth's radii, both planets b and c have densities that could classify them as gaseous mini-Neptunes. This demonstrates that both accurate mass and radius are crucial in order to classify planets correctly, and ultimately will improve only with asteroseismology carried out from space (García & Ballot 2019). Since planet d has only a lower mass limit, it can either be a gaseous mini-Neptune or a rocky super Earth.…”