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Full-Text Articles in Physical Sciences and Mathematics
Bayesian Inference For The White Dwarf Initial-Final Mass Relation, Nathan Stein, Ted Von Hippel, David Van Dyk, Steven Degennaro, Elizabeth Jeffery, Bill Jefferys
Bayesian Inference For The White Dwarf Initial-Final Mass Relation, Nathan Stein, Ted Von Hippel, David Van Dyk, Steven Degennaro, Elizabeth Jeffery, Bill Jefferys
Publications
Stars lose mass as they age, and understanding mass loss is important for understanding stellar evolution. The initial-final mass relation (IFMR) is the relationship between a white dwarf’s initial mass on the main sequence and its final mass. We have developed a new method for fitting the IFMR based on a Bayesian analysis of photometric observations, combining deterministic models of stellar evolution in an internally coherent way. No mass data are used. Our method yields precise inferences (with uncertainties) for a parameterized linear IFMR. Our method can also return posterior distributions of white dwarf initial and final masses.
Improving White Dwarfs As Chronometers With Gaia Parallaxes And Spectroscopic Metallicities, Adam Moss, Ted Von Hippel, Elliot Robinson, Kareem El-Badry, David C. Stenning, David Van Dyk, Morgan Fouesneau, Coryn A.L. Bailer-Jones, Elizabeth Jeffery, Jimmy Sargent, Isabelle Kloc, Natalie Moticska
Improving White Dwarfs As Chronometers With Gaia Parallaxes And Spectroscopic Metallicities, Adam Moss, Ted Von Hippel, Elliot Robinson, Kareem El-Badry, David C. Stenning, David Van Dyk, Morgan Fouesneau, Coryn A.L. Bailer-Jones, Elizabeth Jeffery, Jimmy Sargent, Isabelle Kloc, Natalie Moticska
Publications
White dwarfs (WDs) offer unrealized potential in solving two problems in astrophysics: stellar age accuracy and precision. WD cooling ages can be inferred from surface temperatures and radii, which can be constrained with precision by high-quality photometry and parallaxes. Accurate and precise Gaia parallaxes along with photometric surveys provide information to derive cooling and total ages for vast numbers of WDs. Here we analyze 1372 WDs found in wide binaries with main-sequence (MS) companions and report on the cooling and total age precision attainable in these WD+MS systems. The total age of a WD can be further constrained if its …
Galactic Open Clusters, Ted Von Hippel
Galactic Open Clusters, Ted Von Hippel
Publications
The study of open clusters has a classic feel to it since the subject predates anyone alive today. Despite the age of this topic, I show via an ADS search that its relevance and importance in astronomy has grown faster in the last few decades than astronomy in general. This is surely due to both technical reasons and the interconnection of the field of stellar evolution to many branches of astronomy. In this review, I outline what we know today about open clusters and what they have taught us about a range of topics from stellar evolution to Galactic structure …
White Dwarfs In Open Clusters: New Tests Of Stellar Evolution And The Age Of The Galaxy, Ted Von Hippel
White Dwarfs In Open Clusters: New Tests Of Stellar Evolution And The Age Of The Galaxy, Ted Von Hippel
Publications
White dwarf cooling theory and very deep observations in star clusters provide a new tool to test stellar evolution theory and time scales. In particular, white dwarf cooling theory is now testing the degree of enhanced core mixing in stars with turnoff ages of 1 to 2 Gyr. More generally, I show the good overall agreement between white dwarf and modern isochrone ages over the range 0.1 to 4 Gyr.