과제 8. Origin of carbon-enhanced metal-poor (CEMP) stars

• 개괄

  • Among metal-poor stars, stars with large carbon-enhancements are called “carbon-enhanced metal-poor (CEMP) stars”. It has been shown that the frequency of CEMP stars increases with decreasing metallicity, which suggests that a large amount of carbon was produced in the early history of the Universe. In addition, according to the level of the enhancement of neutron-capture elements, the CEMP stars can be further divided into several subclasses. In this project, we would like to investigate the production mechanism of each CEMP subclass.

     

• 질문

  • How can you divide CEMP stars into each subclass? What are the general criteria?

  • What is the nature of each subclass? Can you identify the likely progenitor(s) of each CEMP subclass?

  • Are some of these objects linked to the first generations of stars? If so, how?

     

• 참고 논문

  1. “The Discovery and Analysis of Very Metal-Poor Stars in the Galaxy” by Beers & Christlieb, 2005, ARA&A, 43, 531

  2. “The Most Metal-poor Stars. IV. The Two Populations with [Fe/H] <~ -3.0” by Norris et al., 2013, ApJ, 762, 28

  3. “The role of binaries in the enrichment of the early Galactic halo. II. Carbon-enhanced metal-poor stars: CEMP-no stars” by Hansen et al., 2016, A&A, 586, 160

  4. “The role of binaries in the enrichment of the early Galactic halo. III. Carbon-enhanced metal-poor stars - CEMP-s stars” by Hansen et al., 2016, A&A, 588, 37

  5. “Abundances of carbon-enhanced metal-poor stars as constraints on their formation” by Hansen et al., 2016, A&A, 58, 37