Hypervelocity Star Candidates in the SEGUE G and K Dwarf Sample

Schneider, Donald P.; Beers, Timothy C.; Lee, Young Sun; Allende-Prieto, C.; Palladino, L. E.; Schlesinger, Katharine J.; Holley-Bockelmann, Kelly
Referencia bibliográfica

The Astrophysical Journal, Volume 780, Issue 1, article id. 7, 7 pp. (2014).

Fecha de publicación:
1
2014
Número de autores
7
Número de autores del IAC
1
Número de citas
44
Número de citas referidas
42
Descripción
We present 20 candidate hypervelocity stars from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) G and K dwarf samples. Previous searches for hypervelocity stars have only focused on large radial velocities; in this study, we also use proper motions to select the candidates. We determine the hypervelocity likelihood of each candidate by means of Monte Carlo simulations, considering the significant errors often associated with high proper motion stars. We find that nearly half of the candidates exceed their escape velocities with at least 98% probability. Every candidate also has less than a 25% chance of being a high-velocity fluke within the SEGUE sample. Based on orbits calculated using the observed six-dimensional positions and velocities, few, if any, of these candidates originate from the Galactic center. If these candidates are truly hypervelocity stars, they were not ejected by interactions with the Milky Way's supermassive black hole. This calls for a more serious examination of alternative hypervelocity-star ejection scenarios.
Proyectos relacionados
spectrum of mercury lamp
Abundancias Químicas en Estrellas
La espectroscopía de estrellas nos permite determinar las propiedades y composiciones químicas de las mismas. A partir de esta información para estrellas de diferente edad en la Vía Láctea es posible reconstruir la evolución química de la Galaxia, así como el origen de los elementos más pesados que el boro, forjados principalmente en los interiores
Carlos
Allende Prieto