Stellar-evolution limits on axion properties

Stellar-Evolution Limits on Axion Properties

If axions exist, they are copiously produced in hot and dense plasmas, carrying away energy directly from the interior of stars. Various astronomical observables constrain the operation of such anomalous stellar energy-loss channels and thus provide restrictive limits on the axion interactions with photons, nucleons, and electrons. In typical axion models a limit ma < ∼ 10 eV is implied. The ma...

Limits on the primordial stellar multiplicity

Most stars especially young stars are observed to be in multiple systems. Dynamical evolution is unable to pair stars efficiently, which leads to the conclusion that star-forming cores must usually fragment into ≥ 2 stars. However, the dynamical decay of systems with ≥ 3 or 4 stars would result in a large single-star population that is not seen in the young stellar population. Additionally, eje...

Stellar evolution on the Asymptotic Giant Branch

Mass loss dominates the stellar evolution on the Asymptotic Giant Branch. The phase of highest mass-loss occurs during the last 1–10% of the AGB and includes the so-called Miras and OH/IR stars. In this review I will discuss the characteristics and evolution of especially Miras, and discuss how they are linked to the mass loss. There are indications that high mass-loss rates are only reached fo...

Stellar Structure and Evolution

Stellar Evolution Presenting

Stars “evolve” with time in a predicable manner. Our theory of stellar evolution is one of the foundations of astrophysics, is well tested and verified, and has enabled great advances in many fields of astrophysics. As such, stellar evolution is a cornerstone of any astronomy course, from the 100 level up through graduate levels. One of the leading software to model a star’s evolution in detail...