Stellar Astrophysics
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Research at Gemini covers the evolution and the atmospheres of stars.
The Hertzsprung-Russell Diagram. Image credit: The Astronomy Magazine.
Dwarf stars:
Massive stars:
Star formation:
White Dwarf Stars:
As the final state of most stars in the Galaxy, white dwarf stars represent one constraint on the process of stellar evolution. Determining their structure and composition tells us how the material they are born with is transformed during their trek across the HR diagram. Becuase the coolest white dwarf stars are also among the oldest stars in the Galaxy (or a particular Galactic component), studying them tells us about the ages of our Galaxy and its various components. Due to their high gravities, acreted metals tend to sink very quickly into white dwarf interiors. Studying surface metalic abundances, therefore, tells us about their recent acretion behavior. White dwarf stars are excellent laboratories for the exploration of matter under extreme conditions due to their subsequent evolution being dominated by cooling, by light and particle radiation. The neutrino luminosity of the hottest white dwarf stars can actually be higher than their photon luminosity, for example.
Our primary tools for studying white dwarf stars are spectroscopy and asteroseismology. The former tells us about their surface composition, temperature, gravities, distance, and mass, while the latter uses their pulsations to provide detailed information about their interior structure and composition, in addition to more global properties like mass, luminosity, age, cooling rate, etc.
Binary systems:
