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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

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Dartmouth Scholarship

2009

Star evolution

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Full-Text Articles in Physical Sciences and Mathematics

Sdss Unveils A Population Of Intrinsically Faint Cataclysmic Variables At The Minimum Orbital Period, B. T. Gänsicke, M. Dillon, J. Southworth, J. R. Thorstensen May 2009

Sdss Unveils A Population Of Intrinsically Faint Cataclysmic Variables At The Minimum Orbital Period, B. T. Gänsicke, M. Dillon, J. Southworth, J. R. Thorstensen

Dartmouth Scholarship

We discuss the properties of 137 cataclysmic variables (CVs) which are included in the Sloan Digital Sky Survey (SDSS) spectroscopic data base, and for which accurate orbital periods have been measured. 92 of these systems are new discoveries from SDSS and were followed-up in more detail over the past few years. 45 systems were previously identified as CVs because of the detection of optical outbursts and/or X-ray emission, and subsequently re-identified from the SDSS spectroscopy. The period distribution of the SDSS CVs differs dramatically from that of all the previously known CVs, in particular it contains a significant accumulation of …


Stellar Population Models And Individual Element Abundances. Ii. Stellar Spectra And Integrated Light Models, Hyun-Chul Lee, Guy Worthey, Aaron Dotter, Brian Chaboyer Apr 2009

Stellar Population Models And Individual Element Abundances. Ii. Stellar Spectra And Integrated Light Models, Hyun-Chul Lee, Guy Worthey, Aaron Dotter, Brian Chaboyer

Dartmouth Scholarship

The first paper in this series explored the effects of altering the chemical mixture of the stellar population on an element-by-element basis on stellar evolutionary tracks and isochrones to the end of the red giant branch. This paper extends the discussion by incorporating the fully consistent synthetic stellar spectra with those isochrone models in predicting integrated colors, Lick indices, and synthetic spectra. Older populations display element ratio effects in their spectra at higher amplitude than younger populations. In addition, spectral effects in the photospheres of stars tend to dominate over effects from isochrone temperatures and lifetimes, but, further, the isochrone-based …